Commissioning Cables and Terminations

Engineering Encyclopedia Saudi Aramco DeskTop Standards

Commissioning Cables And Terminations

Note: The source of the technical material in this volume is the Professional Engineering Development Program (PEDP) of Engineering Services. Warning: The material contained in this document was developed for Saudi Aramco and is intended for the exclusive use of Saudi Aramco’s employees. Any material contained in this document which is not already in the public domain may not be copied, reproduced, sold, given, or disclosed to third parties, or otherwise used in whole, or in part, without the written permission of the Vice President, Engineering Services, Saudi Aramco.

Chapter : Electrical File Reference: EEX30103

For additional information on this subject, contact W. A. Roussel on 874-1320

Engineering Encyclopedia

Electrical Commissioning cables and terminations

Contents

Page

SAUDI ARAMCO APPLICATIONS AND REQUIREMENTS FOR LOW VOLTAGE CABLES.......................... 1 EVALUATING LOW VOLTAGE CABLES UPON RECEIPT............. 4 EVALUATING LOW VOLTAGE CABLE TESTING AND INSTALLATION ....................................................... 6 LOW VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE................................................. 15 SAUDI ARAMCO REQUIREMENTS FOR MEDIUM/HIGH VOLTAGE CABLES .............................................. 16 EVALUATING MEDIUM/HIGH VOLTAGE CABLES UPON RECEIPT .............................................................. 18 EVALUATING MEDIUM/HIGH VOLTAGE CABLE TESTING AND INSTALLATION ..................................................... 20 MEDIUM/HIGH VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE 26 WORK AID 1: REFERENCES FOR EVALUATING LOW VOLTAGE CABLES UPON RECEIPT 27 WORK AID 2: REFERENCES FOR EVALUATING LOW VOLTAGE CABLE INSTALLATION AND TESTING ..................................................... 32 WORK AID 3:REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGE CABLES UPON RECEIPT .............................................................. 49 WORK AID 4: REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGE CABLE INSTALLATION AND TESTING ........................................ 54 GLOSSARY..................................................................................... 84

Saudi Aramco DeskTop Standards



SAUDI ARAMCO APPLICATIONS AND REQUIREMENTS FOR LOW VOLTAGE CABLES Low voltage cables in Saudi Aramco electric power systems are defined as cables that are rated to carry voltages 1000 V and below. Low voltage power cables are usually cables that supply power to small feeders, which, in turn, supply power to small motors, lights, or auxiliary equipment. Low voltage cables also supply control power to breakers, protective devices, and auxiliary and safety systems. When a low voltage cable is selected for an installation, the cable should be of the proper type and size to handle the nominal and fault transient currents without damage from excess heat generation or a loss of system voltage regulation. The proper cable, cable splices, and cable terminations are selected by the facility design personnel before the cable is installed. This section will describe the following topics that pertain to the applications and requirements for low voltage cables: • •

Types of Low Voltage Cables Types of Low Voltage Cable Terminations and Splices

Types of Low Voltage Cables A power cable is defined as a conductor or a group of conductors that supplies current for the proper operation of a machine, apparatus, or system during start-up, normal operation, and transient conditions. The types of cables that are acceptable for use in Saudi Aramco installations are described in SAES-P-104, SADP-P-104, and Module EEX 206.04, Selecting and Sizing Cables for Saudi Aramco Installations. A list of the types of low voltage power cables that are acceptable for use in Saudi Aramco installations is provided in Figure 13 of Work Aid 1. The following is a list of the common abbreviations that are used for cables and wires. These abbreviations should be understood in order to interpret some of the information that is provided in Figure 13 of Work Aid 1. AC ALS CLX CSP DB EPR FC IAC


-

Armor Clad Aluminum Sheathed Cable Corrugated Sheathed (Okonite Trademark) Chloresulphonated Polyethylene (Hypalon) Direct Buried Ethylene Propylene Rubber (EPD, EPDM) Flat Cable Interlocked Armor Cable

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Types of Low Voltage Cables (Cont'd) MC MV NM NMC PE PILC(A) PVC SBR SE SNM SWA TC UF USE VCLC(A) WP -

-

Metal Clad Cable Medium Voltage Cable Nonmetallic Sheathed Cable Nonmetallic Sheathed, Corrosion Resistant Cable Polyethylene Paper Insulated Lead Covered (Armored) Cable Poly Vinyl Chloride Styrene Butadiene Rubber Service Entrance Cable Shielded Nonmetallic-Sheathed Cable Steel Wire Armor Tray Cable Underground Feeder Cable Underground Service Entrance Cable Varnished Cambric Lead Covered (Armored) Cable Weatherproof

When power cable is selected, the type of cable that is chosen is based on the particular application of the cable and the conditions to which the cable will be subjected. For Saudi Aramco installations, the selection of a type and size of a power cable is based on the following criteria: •

The technical requirements of the new installation (or installation modification), which include parameters such as voltage level, current loading, ambient temperature, voltage regulation, and fault current.

•

The installation requirements of the existing (or planned) facilities, such as the use of ducts, conduit, or trays.

•

The economic requirements that are based on the selection of a suitable cable. The economic requirements should take into account the required accessories and auxiliary structures that are associated with the selected cable, as well as the actual installation of the cable.

Control cables that are used in Saudi Aramco installations are also low voltage cables. A control cable is defined as a conductor or a group of conductors that regulates or guides the operation of a machine, apparatus, or system. Electrical control cables consist of various combinations of circuits that are used to control the operation of electrical systems. Examples of electrical control cable use include electric power control, starting and stopping


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Types of Low Voltage Cables (Cont'd) of equipment, relay operations, switch operations, direct system status indications, and equipment automation. Electronic control cables consist of various combinations of circuits that are used to control the operation of electronic systems. Examples of electronic control cable use include data logging, computer interconnection, data inputs, data outputs, system control, and instrumentation. A list of the applications of control cables that are acceptable for use in Saudi Aramco installations is provided in Figure 15 of Work Aid 1. The Insulated Cable Engineers Association (ICEA) has classified single- and multi-conductor control cable installations into four types of service. A table that describes the four ICEA control cable service classifications is provided in Work Aid 1. Types of Low Voltage Cable Terminations and Splices When a cable is ordered from the manufacturer that meets the specifications of an installation, the cable should function properly throughout its operational life. The main causes of cable failure are damage during installation and improper splices or terminations. The preferred methods for terminating solid-dielectric cables and recommended cable terminators are provided in Work Aid 1. A separate table that highlights the types of cable terminations and splices that are allowed in Saudi Aramco installations and the types of cable terminations and splices that are not allowed in Saudi Aramco installations are provided in Work Aid 2. Because a cable that is connected to a load in an energized state carries current, the cable generates heat during use. High temperatures can cause embrittlement and degradation of the insulation that can lead to shorts between phases or from phase to ground. When a cable conductor is terminated, the termination has more electrical resistance than the cable conductor. The increased electrical resistance at a termination generates more heat than the cable conductor that it terminates. The heat that is generated at a cable termination is dissipated through the outer covering or insulating material of the termination. Because of the increased electrical resistance at a termination, some terminals have temperature ratings. Information on the temperature ratings of a terminal can be found in the terminal construction kit that is provided by the manufacturer.


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EVALUATING LOW VOLTAGE CABLES UPON RECEIPT The installation of wire and cable systems is a process that takes place over a period of time. The installation begins with an identified need for a new installation (e.g., a new processing plant). Because power is necessary for the new installation to function, a new wire or cable power distribution or control system is designed. After the system design is approved, the equipment for the wire or cable installation (e.g., cable or conduit) is ordered. Once the cables are received, they must be evaluated to ensure that they are proper for the installation. The purpose of the evaluation is to verify that the correct cable was received from the manufacturer and that the proper installation specifications and parameters are met. This section of the Module provides information on the following topics that are pertinent to evaluating low voltage cables upon receipt: • •

Visual Inspection Verify Against Specifications

Visual Inspection When low voltage cable is received from the manufacturer, a visual inspection should be performed. The purpose of the visual inspection is to verify that the cable that was received from the manufacturer is in good physical condition. A cable is in good physical condition if it has no chips, cuts, nicks, gouges, or other possible shipping damage or manufacturer defects. Because cables are usually shipped and stored on reels, the cable must be unrolled to perform a detailed inspection. Due to the difficulties that are involved in unreeling large lengths of cable, a short length of the cable is usually unrolled at the receiving point, and a cursory inspection is performed. A detailed inspection of the low voltage cable is performed when the cable is being pulled into the raceway or cable tray at the installation site. Verify Against Specifications When a new facility or facility modification is at the equipment installation stage, the design of the installation has already been completed. The type of low voltage cable that is selected for a specific power system should be shown in the drawings, prints, or specifications for the installation. The purpose of verifying low voltage cable against the specifications is to ensure that the cable that is to be installed meets Saudi Aramco and industry standards. Generally, the verification against specifications consists of a determination of whether the size and type of cable that is to be installed matches the size and type of cable that is required for the installation. In some cases, this determination is accomplished by reading an electrical plan that identifies the cable sizes and types. The Engineer then only has to inspect the manufacturer's markings on each cable and compare them to the requirements


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Verify Against Specifications (Cont'd) on the electrical plan to determine whether the correct cable is being used. In other situations, the Electrical Engineer must rely on his knowledge of the correct application of cable sizes and types and must then determine whether the correct cable is being used. A list of the items that should be included in a preinstallation inspection to verify a low voltage cable against specifications is provided in Work Aid 1.


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EVALUATING LOW VOLTAGE CABLE TESTING AND INSTALLATION Throughout the complicated and detailed installation and commissioning process for electric power distribution wire or cable, various installation tests and inspections should be performed. The installation tests and inspections ensure that the installation meets Saudi Aramco and industry requirements and specifications. Electrical tests are performed to check the ability of a conductor to operate for a reasonable future period of time under all operating conditions and loads. Failure of a cable under test conditions will usually cause an in-test breakdown of the cable, or it will indicate the need for its immediate replacement. Industry experience has shown that the failure rate of cables is highest for relatively new cables. When a cable is being commissioned, an acceptance or installation test should be made after the cable is installed but before the cable is placed into normal service. These acceptance or installation tests should detect shipping or installation damage, gross cable defects, or errors in workmanship in splices and terminations. During the wire or cable installation process, installation inspections should be performed. The purpose of the installation inspections is to verify that the proper cable installation materials are used, that the installation specifications and parameters are met, and that the proper installation procedures are followed. The installation inspections are conducted to ensure that the wire or cable will function properly after installation. This section of the Module provides information on the following topics that are pertinent to evaluating low voltage cable testing and installation: • • • •

Insulation Resistance (Megger) Test Hi-Pot 2 kV DC Test Cable Tensiometer (Strain Gage) and Pulling Devices Point-to-Point Verification of Cables

Insulation Resistance (Megger) Test The purpose of the insulation resistance (megger) test is to directly measure the insulation resistance of the cable. The megohmmeter test is most useful for low voltage cables. In the megohmmeter test, the megger is used to set up an electromagnetic field, and the field that is created is used to produce leakage currents that will flow through the insulation that is between the cable conductor and ground. The amount of leakage current flow that is detected through use of the megger results in a megger meter readout of insulation resistance (in megohms).


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Insulation Resistance (Megger) Test (Cont'd) For low voltage cables, megohmmeter test voltages are provided on the Saudi Aramco PreCommissioning Form, P-004, Low Voltage Cables, which is provided in Figure 18 of Work Aid 2. Figure1 shows the megger voltage values that Form P-004 lists for low voltage cable commissioning in Saudi Aramco facilities. Cable Rating

Megger Used

250 V and below

250 V

250 V to 600 V

1000 V

Above 600 V and less than1200 V

2500 V

Table of Low Voltage Cable Megger Voltages (From Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables) Figure 1 To conduct the megohmmeter test, the megger is connected between two of the cable conductors (phases), and the megger is operated. Similar megger readings are taken between each remaining conductor (phase) pair combination and between each cable conductor (phase) and ground. When a megger is used to measure low voltage cable insulation resistance, the megger is operated for 60 seconds. At the end of the 60-second period, the megger readings are taken even though the megger pointer may still be climbing. The practice of 60-second megger readings will provide reliable comparisons for future analysis. Figure 2 shows a typical curve of insulation resistance. In Figure 2, a 60-second resistance value is taken and recorded. The typical curve illustrates that the resistance value (in megohms) does not rise linearly over time. This nonlinear rise of resistance is due to the capacitive properties of the insulating material.


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Insulation Resistance (Megger) Test (Cont'd) Use Word 6.0c or later to

view Macintosh picture.

Typical Curve of Insulation Resistance Figure 2 When the cable insulation resistance test is performed, both ends of the cable must be disconnected to avoid errors due to components that are connected to the other end of the cable. Figure 3 shows how a megger is used to measure phase 1 of a three-conductor cable.


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Insulation Resistance (Megger) Test (Cont'd)

Use Word 6.0c or later to


Megger of Phase 1 Figure 3 For new cable installations, the megohmmeter test should be conducted on all new cables before they are unreeled and immediately after they are installed. The megohmmeter test will detect gross imperfections or damage that would result in cable failure upon energization. When new cable is spliced to old cable, a megohmmeter test should be performed on the complete circuit prior to commissioning.


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Insulation Resistance (Megger) Test (Cont'd) The Electrical Engineer should evaluate the insulation resistance (megger) test values to ensure that the insulation resistance values that were recorded are greater than the manufacturer's minimum values. If the manufacturer's minimum values are not provided, the values of the insulation resistance should be greater than the rated voltage + 1 kV in megohms. Any value of insulation resistance that is less than the minimum specifications should be investigated by the Electrical Engineer who performs the test data evaluation. An example series of megger tests was performed on a three-conductor cable. Figure4 shows typical megger test data records. Evaluation of the example test results shows that all three phases of the cable have adequate insulation resistance, both phase-to-phase and phase-toground. The example test data indicate that the cable is satisfactory to use. Resistance Test (Megger) Phase Meg. Ohms Phase 1 to 2 700 M½ Phase 2 to 3 630 M½ Phase 3 to 1 700 M½ Phase 1 to G 300 M½ Phase 2 to G 230 M½ Phase 3 to G 310 M½ Sample Megger Results Figure 4 The ratio of two time-resistance readings (such as a 60-second reading that is divided by a 30second reading) is called a dielectric absorption ratio. If the ratio is a ten-minute reading that is divided by a one-minute reading, the value is called the polarization index. The dielectric absorption ratio reading can be used to evaluate the condition of the cable insulation. When a hand-cranked megger instrument is used, the insulation resistance reading is taken for only 60 seconds. When a power-operated megger instrument is used, a reading is taken for a full ten minutes. Readings that are taken at one minute and ten minutes will yield the polarization index. An explanation of the evaluation of the megger readings is provided in Work Aid 2.


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Hi-Pot 2 kV DC Test Although the dc high potential test is listed on Form P-004, this test is optional and is not conducted in Saudi Aramco on low voltage cables. The purpose of a dc high potential (hipot) test on low voltage cables is to identify internal faults in or damage to the low voltage cable insulation system. The hi-pot test will identify these faults so that corrective action can be taken. The hi-pot test should be performed or conducted before initially energizing a cable but after a megohmmeter test. Normally, the dc hi-pot test is conducted one month after the cable has been initially energized. The dc hi-pot testing technique for cables involves the measurement of increased dc voltage that is applied to the cable insulation under test. The value of the leakage current as the test voltage is increased through several steps is tracked, and this value becomes a criterion of the condition of the insulation. When the dc hi-pot test is correctly performed, the test will have no deteriorating effect on good insulation as long as the test voltage is kept within prescribed limits. The effect of the dc hi-pot testing on poor insulation or poor workmanship is to increase the deterioration of the material and, in many cases, a fault can be induced by the test. An introduction of a fault to a cable with poor insulation or poor workmanship is desirable. Once the probable fault area is broken down, the location of the fault can be found and a repair can be initiated. Although gross imperfections or damage can be detected immediately, the dc hi-pot test is relatively ineffective in the detection of moderate defects or damage in new cable installations. As stated previously, gross imperfections or damage can be detected from a simpler megohmmeter test. After a period of ac energization, deterioration will start in problem areas. The dc hi-pot test is most effective once the deterioration has begun. Before the dc hi-pot test is conducted, certain precautions must be taken. Any cable that is under test should have both end terminations free from all equipment. Cables of the same circuit that are not under test should be grounded in addition to all cable support equipment (e.g., metallic armor, sheaths, conduit, and trays). A visual check of all exposed portions of the cable run should be made to determine whether any abnormalities exist in the cable. The condition and continuity of all grounding equipment (e.g., clamps, wires, and rods) should also be noted. For low voltage cables, dc hi-pot test voltages are provided on the Saudi Aramco PreCommissioning Form, P-004, Low Voltage Cables, which is provided in Work Aid 2. A maximum voltage value of 2000 V is used during the dc hi-pot test for low voltage cables that are rated for voltages from 250 V to 1000 V. The dc hi-pot test is conducted in a minimum of four steps. Voltage is increased to the maximum voltage value in steps that are an order of magnitude of the rated ac rms voltage of the cable. Each voltage step is held


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Hi-Pot 2 kV DC Test (Cont'd) for a one-minute duration. For 600 V cable, voltage increments of approximately 500 V should be used. During the dc hi-pot test, the leakage current should be plotted against time at the end of each timing interval. Figure 5 illustrates representative current-time curves over a ten-minute test period. The curves in Figure 5 show that good insulation exhibits a steady decrease in leakage current with time, and bad insulation exhibits a rise in leakage current. Any rise in leakage current during this test is a signal to stop the test. The polarization index can be calculated from this test data by dividing the leakage current after one minute by the leakage current that is obtained after ten minutes, as follows: Use Word 6.0c or later to


Hi-Pot Current-Time Characteristics Figure 5


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Hi-Pot 2 kV DC Test (Cont'd) High voltage dc test potentials are lethal. All safety precautions and operational procedures must be carefully followed. The rate of increase of the test voltages should be approximately uniform. The maximum rate of increase of the test voltages is 100 percent in ten seconds, and the minimum rate of increase is 100 percent in 60 seconds. The test should be stopped at the first indication of an upward bend or knee in the curve. A knee in the curve indicates the need for cleaning and drying of cable insulation, and, if the test is not stopped, the leakage current may increase to a value that may damage the insulation. When the dc hi-pot test is completed, the charge in the cable should be allowed to drain off. The test charge drain is accomplished by setting the test voltage dial to zero. The charge drains off through leakage in the test set and voltmeter circuits. A one-megohm resistor can be added to the drainage path if desired. When the cable has dropped to ten percent of its test voltage, it should be solidly grounded for at least 30 minutes after removal of the dc test voltage. Complete isolation of cables from splices, terminations, and associated equipment (e.g., switches and current transformers) is not always practical. Any equipment that is not isolated from the cable that is tested will be tested along with the cable. In many cases, because the connected equipment will not withstand the applied test voltage, the voltage test potential should be reduced accordingly. Cable Tensionometer (Strain Gage) and Pulling Devices If the cable is to be installed in a cable tray or conduit, the cable pull method is determined prior to the cable installation. The curves and bends within the selected installation route, the type of pulling equipment, and the lengths of each route segment are all used to calculate specific pulling tensions that will act on the cable and cable pulling equipment throughout the pull. Maximum cable tensions are calculated for various pulling directions and cable lengths, and a final cable pulling schedule is determined. The proper cables and pulling equipment are then staged at the various pulling points throughout the length of the cable pull. The highest probability for cable damage occurs during the installation process. If the correct cable pulling methods are used and if the maximum pulling tensions are not exceeded, the cable should be installed without damage to the cable or to the cable support system. The purpose of conducting an evaluation of the cable pulling process is to ensure that the cable pulling methods are correct and that the cable pulling tensions do not exceed the maximum values that were determined during the design phase of the installation.


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To evaluate the cable pulling process, personnel should visually observe that the correct cable and cable pulling equipment or devices are used in the cable pull through performance of visual checks at both ends of the pull (or pulls). Cable tensiometer (strain gage) checks are performed throughout the pull (or pulls) to ensure that the maximum cable pulling tensions are not exceeded. A general procedure to evaluate the strain gage and pulling devices is provided in Work Aid2. Point-to-Point Verification of Cables During a cable installation process, the cable is installed along the route that was chosen for the installation. A facility installation can have many different power and control cables that are required to be installed, and the cables sometimes share routes (e.g., conduit and cable trays) for engineering and economic reasons. A point-to-point verification of the cable installation is performed before and during the cable installation process to ensure that the correct cable is being installed along the correct route. In an industrial facility, plant or system conditions can change over time. Because a time lag can occur between the initial design of a cable installation and the actual installation process, the cable route should also be checked during the point-to-point verification. The cable route check that is performed during the point-to-point verification can uncover routing problems that may not have existed at the design phase of the cable installation. Additionally, some routing problems may not become clear until the cable is actually being installed. A list of the items that should be included in a point-to-point verification of low voltage cables is provided in Work Aid 2. During the point-to-point verification, the installation of the cable terminations and splices should be inspected. The purpose of performing the evaluation of the low voltage cable terminations and splices is to determine whether the low voltage cables have been correctly terminated or spliced. The main causes of cable failure are damage during installation and improper splices or terminations. An evaluation of cable splices and terminations can uncover problems or installation errors. The identification of problems or errors prior to placing a cable in service can prevent costly repairs or replacements later in the operational life of the cable. To conduct the low voltage cable termination and splice evaluation, inspection personnel should visually check all terminations and splices during a "walk down" of the installation. A visual check of all terminations and splices is performed to ensure that the terminations and splices match the drawings, prints, or specifications for the installation. A list of the items that should be included in the low voltage cable termination and splice evaluation is provided in Work Aid2. A general cable termination and splice evaluation procedure is also provided in Work Aid 2.


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LOW VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE The operational testing phase of the commissioning cycle provides an opportunity for Saudi Aramco personnel to perform the following: • •

System source feed compatibility checks Complete system functional test

System source feed compatibility checks are performed on low voltage cables through application of the full system voltage onto the cable. With the voltage applied, voltage phasing, synchronizing, device rotation, and other source feed compatibility checks are performed. Parallel or alternate power source feed operations are also performed to ensure the total operation of the major components of the low voltage cable system. A complete system functional test is performed on low voltage cables to ensure that the entire low voltage cable system functions in accordance with the system design. During the complete system functional test of low voltage cables, the cables are allowed to assume a fully-loaded condition for a period of time that is adequate to obtain the maximum system temperature. In special circumstances, cable temperatures are monitored after the loaded time period. The low voltage cable temperatures can be monitored locally through use of temperature monitoring equipment or through use of thermographic surveys. When such monitoring is conducted, particular attention should be paid to splice and termination points during the complete system functional test. Infrared thermography can be used to detect hot spots and abnormal cable temperature conditions.


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SAUDI ARAMCO REQUIREMENTS FOR MEDIUM/HIGH VOLTAGE CABLES Medium voltage cables in Saudi Aramco electric power systems are defined as cables that are rated to carry voltages that are greater than 1000 V but that are less than 69 kV. High voltage cables are cables that are 69 kV and greater. Medium and high voltage cables are selected for an installation in a manner similar to the selection of low voltage cable; the cable should be of the proper type and size to handle nominal and fault transient currents without damage from excess heat generation or a loss of system voltage regulation. The proper cable, cable splices, and cable terminations are selected by the facility design personnel before the cable is installed. This section of the Module provides information on the following topics that are pertinent to the requirements for medium/high voltage cables: • •

Types of Medium/High Voltage Cables Types of Medium/High Voltage Cable Terminations and Splices

Types of Medium/High Voltage Cables The types of cables that are permitted in Saudi Aramco installations are described in SAES-P104, SADP-P-104, and Module EEX 206.04, Selecting and Sizing Cables for Saudi Aramco Installations. A list of the types of medium/high voltage power cables that are permitted in Saudi Aramco installations is provided in Figure 24 of Work Aid 3. A list of the common abbreviations that are used for cables and wires is provided in the first section of this information sheet. The basis for the selection of medium/high voltage power cable is as follows: •

The technical requirements of the new installation (or installation

•

The installation requirements of the existing (or planned) facilities.

•

The economic requirements of the existing (or planned) facilities.

modification)

Types of Medium/High Voltage Cable Terminations and Splices As with low voltage cables, when a medium/high voltage cable that has been ordered from the manufacturer and if the cable meets the specifications of the installation, the cable should properly operate throughout its projected operational life. The main causes of cable failure are damage during installation and improper splices or terminations. The preferred


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Types of Medium/High Voltage Cable Terminations and Splices (Cont'd) methods for terminating medium/high voltage, solid-dielectric cables and recommended cable terminators are provided in Work Aid 3. A separate table that highlights the types of cable terminations and splices that are permitted in Saudi Aramco installations and the types of cable terminations and splices that are not permitted in Saudi Aramco installations are provided in Work Aid 4. Because a cable in an energized state carries current, the cable generates heat during use. High temperatures can cause embrittlement and degradation of the insulation, which can lead to shorts between phases or from phase to ground. When a cable conductor is terminated, the termination has more electrical resistance than the cable conductor. The increased electrical resistance at a termination generates more heat than the cable conductor that it terminates. The heat that is generated at a cable termination is dissipated through the outer covering or insulating material of the termination. Because of the increased electrical resistance at a termination, some terminals have temperature ratings. Information on the temperature ratings of a terminal can be found in the terminal construction kit that is provided by the manufacturer.


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EVALUATING MEDIUM/HIGH VOLTAGE CABLES UPON RECEIPT The installation of wire and cable systems is a process that takes place over a period of time. The installation begins with an identified need for a new installation (e.g., a new processing plant). Because power is necessary for the new facility to function, a new wire or cable power distribution or control system is designed, and the equipment is ordered from the manufacturer. Medium/high voltage cables that are received from the manufacturer must be evaluated to ensure that they are proper for the installation. The purpose of the evaluation is to verify that the correct cable was received from the manufacturer and that the proper installation specifications and parameters are met. This section of the Module provides information on the following topics that are pertinent to evaluating medium/high voltage cables upon receipt: • • •

Visual Inspection Verify Against Specifications Determine/Locate Manufacturer Test Documentation

Visual Inspection When medium/high voltage cable is received from the manufacturer, a visual inspection of the cable should be performed to verify that the cable that was received from the manufacturer is in good physical condition. A cable is in good physical condition if it has no visible chips, cuts, nicks, gouges, or other possible shipping damage or manufacturer defects. If the medium/high voltage cable is shielded or armored, a visual inspection can only be made of the outermost layer. Because cables are usually shipped and stored on reels, the cable must be unrolled to perform a detailed inspection. Because of the difficulties that are involved in unreeling large lengths of heavy medium/high voltage cables, a cursory inspection is performed at the receiving point. A detailed inspection of medium/high voltage cable is performed when the cable is being pulled into the raceway or cable tray at the installation site. Verify Against Specifications When a new facility or facility modification is at the equipment installation stage, the design of the installation has already been completed. The type of medium/high voltage cable that is selected for a specific power system should be shown in the drawings, prints, or specifications for the installation. Medium/high voltage power cables should be verified against the Saudi Aramco and industry specifications to ensure that the cable that is to be installed meets these specifications.


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Verify Against Specifications (Cont'd) Generally, the verification against specifications consists of a determination of whether the size and type of cable that is to be installed matches the size and type of cable that is required for the installation. In some cases, this determination is accomplished by reading an electrical plan that identifies the cable sizes and types. The Engineer then only has to inspect the manufacturer's markings on each cable and compare them to the requirements on the electrical plan to determine whether the correct cable is being used. In other situations, the Electrical Engineer must rely on his knowledge of the correct application of cable sizes and types and must then determine whether the correct cable is being used. A list of the items that should be included in a preinstallation inspection to verify a medium/high voltage cable against specifications is provided in Work Aid 3. Determine/Locate Manufacturer Test Documentation The manufacturer should perform inspections and tests on medium/high voltage cable before the cable is shipped to Saudi Aramco. When a medium/high voltage cable is received from the manufacturer, any cable test data should be provided in the shipment. The receiving personnel should examine the cable manufacturer inspection and test documentation and verify that the received cable has the ability to provide the service for which it is intended. The verification is performed through comparison of the manufacturer inspection and test documentation with the Saudi Aramco medium/high voltage cable installation drawings or prints. When the medium/high voltage cable is satisfactorily verified, the manufacturer inspection and test data become a permanent part of the cable material history. Inspections, tests, and repairs are performed on medium/high voltage cable from the installation and commissioning of the cable to the final removal of the cable from service. Any data from the inspections, tests, and repairs are documented and kept as part of the material history of the associated medium/high voltage cable. Material history records of medium/high voltage cable installations can show possible trends toward failure. Because steps can be taken (or maintenance can be performed) to correct a problem before damage occurs, knowledge of impending failure is important. The ability to correct a problem before damage occurs can minimize equipment down-time and reduce overall plant costs. Material history records can also amplify specific cable design flaws that would allow Design Engineers to choose different cable or cable support equipment for future installations.


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EVALUATING MEDIUM/HIGH INSTALLATION

VOLTAGE

CABLE

TESTING

AND

Various installation tests and inspections are performed on medium/high voltage cable to ensure that the installation meets Saudi Aramco and industry requirements and specifications. The installation tests and inspections that are performed on medium/high voltage cable are similar to the installation tests and inspections that are performed on low voltage cable. Electrical tests are performed to check the ability of a conductor to operate for a reasonable future period of time under all operating conditions and loads. When a medium/high voltage cable is being commissioned, an acceptance or installation test should be made after the cable is installed but before the cable is placed in normal service. These acceptance or installation tests should detect shipping or installation damage, gross cable defects, or errors in workmanship in splices and terminations. Installation inspections are performed to verify that proper medium/high voltage cable installation materials are used, that installation specifications and parameters are met, and that proper installation procedures are followed. The installation inspection is conducted to ensure that the wire or cable will function properly when installed. This section of the Module provides information on the following topics that are pertinent to evaluating medium/high voltage cable testing and installation: • • • •

Insulation Resistance (Megger) Test DC Hi-Pot Test Cable Tensionometer (Strain Gage) and Pulling Devices Point-to-Point Verification of Cables

Insulation Resistance (Megger) Test The purpose of the medium/high voltage cable insulation resistance (megger) test is to directly measure the cable insulation resistance. Due to the extremely high resistance of wellmade, medium/high voltage cable, a megohmmeter test will only detect gross defects in material or workmanship. Because of the "pass/fail" nature of the insulation resistance test, it only proves valuable as an initial acceptance test on high voltage cable. The megohmmeter test that is performed on medium/high voltage cables is conducted in an identical manner to the megohmmeter test that is performed on low voltage cables. For medium/high voltage cables, the megohmmeter test voltage should be 5,000 V for cables that are rated for 5,000 V and above.


20



Insulation Resistance (Megger) Test (Cont'd) For new medium/high voltage cable installations, the megohmmeter test should be conducted on all new cables before unreeling and immediately after installation. The megohmmeter test will detect gross imperfections or damage that would result in cable failure upon energization. When new cable is spliced to old cable, a megohmmeter test should be performed on the complete circuit prior to commissioning. The Electrical Engineer should evaluate the insulation resistance (megger) test values to ensure that the insulation resistance values that were recorded are greater than the manufacturer's minimum values. If the manufacturer's minimum values are not provided, the values of the insulation resistance should be greater than the rated voltage + 1 kV in megohms. For example, a 13.2 kV rated system should have a measured insulation resistance that is greater than 14.2 megohms. Any value of insulation resistance that is less than the minimum specifications should be investigated by the Electrical Engineer who performs the test data evaluation. The dielectric absorption ratio and polarization index are useful in the performance of an evaluation of the test data. Explanations of the evaluation of the dielectric absorption ratio and polarization index are provided in Work Aid 4. DC Hi-Pot Test The dc hi-pot test is required for new cables (5 kV and above) and splices between new cables prior to commissioning. When new cable is spliced to old cable, a dc hi-pot test of the new cable is performed prior to the installation of the splice. The purpose of the dc hi-pot test that is performed on medium/high voltage cables is to identify internal faults in, or damage to, the medium/high voltage cable insulation system. The dc hi-pot test will show these faults so that corrective action can be taken. The dc hi-pot test should be done before initially energizing a medium/high voltage cable but after a megohmmeter test. Normally, the dc hi-pot test is conducted one month after the cable has been initially energized. The dc hi-pot testing technique that is used for medium/high voltage cables involves the measurement of increased dc voltage that is applied to the insulation under test. The value of the leakage current is tracked as the test voltage is increased through several steps, and this value becomes a criterion of the condition of the insulation. The precautions that are taken and the general procedure of the medium/high voltage cable dc hi-pot test are similar to the low voltage cable dc hi-pot test. The major difference between the low and medium/high voltage cable dc hi-pot tests is the voltage values that are used during the test. The medium/high voltage cable dc hi-pot test is conducted through application of the voltage value that is indicated in Figure 6. The maximum voltage value


21



DC Hi-Pot Test (Cont'd) is reached in a minimum of four steps. Each step should be an order of the rated ac rms voltage of the cable. Each voltage step should be maintained for a one-minute duration. The maximum allowable test level should be maintained for the time periods that are indicated in Figure 6. For commissioning cables that are spliced to old cables, the final dc test voltage should not exceed 65 percent of the test voltage. For commissioning cables that are spliced to extremely old cables with low megger readings, a final voltage that is equal to two times the operating voltage plus two kilovolts is recommended. Representative leakage current-time curves over a ten-minute period for the medium/high voltage cable dc hi-pot test (based on Saudi Aramco Pre-Commissioning Form P-005, Medium Voltage Cables, and P-006, High Voltage Cables) are provided in Work Aid 4.


22



DC Hi-Pot Test (Cont'd) DC Test Voltages - EPR and XLPE Cables (ICEA / AEIC Tests) Insulation Maximum DC Test Voltages (kV) Cable Thickness 100% 80% (3) 75% (2) 65% (4) Rating 100% 133% (kV) A B A B A B A B A B mm mils mm mils 5 2.28 90 2.92 115 35 45 28 36 26 34 23 29 8 2.92 115 3.56 140 45 55 36 44 34 41 29 36 15 4.45 175 5.59 220 70 80 56 64 53 60 46 52 25 6.60 260 8.13 320 100 120 80 96 75 90 65 78 35 8.76 345 10.67 420 125 155 100 124 94 116 81 101 69EPR 16.51 650 240 192 180 156 69XLP 16.51 650 240 192 180 156 115 20.32 800 300 240 225 195 A = 100 percent insulation level. B = 133 percent insulation level. (1)

Thicknesses are for conductor sizes 500 sq mm (1 000 MCM) or less. Test voltages apply to all conductor sizes.

(2)

The 75 percent test may be made at any time during installation. Application time is 5 consecutive minutes.

(3)

The 80 percent test may be made after installation but before the cable is placed in service. Application time is 15 minutes.

(4)

The 65 percent test may be made after the cable is installed and placed in service. Application time is 5 minutes. The 65 percent test applies to cables that are less than five years old.

Medium/High Voltage Cable DC Hi-Pot Test Voltages (Based on Saudi Aramco Pre-Commissioning Forms P-005, Medium Voltage Cables, and P-006, High Voltage Cables) Figure 6


23



DC Hi-Pot Test (Cont'd) During the conduct of the medium/high voltage dc hi-pot test, the rate of increase of the test voltages should be approximately uniform. The maximum rate of increase of the test voltages is 100 percent in ten seconds, and the minimum rate of increase is 100 percent in 60 seconds. The test should be stopped at the first indication of an upward bend or knee in the curve. A knee in the curve indicates the need for cleaning and drying, and, if the test is not stopped, the leakage current may increase to a value that may damage the insulation. At the completion of the test, the charge in the cable should be allowed to drain off. The test charge drain is accomplished by setting the test voltage dial to zero. The charge drains off through leakage in the test set and voltmeter circuits. A one-megohm resistor can be added to the drainage path if desired. When the cable has dropped to ten percent of its test voltage, it should be solidly grounded for at least 30 minutes after removal of the dc test voltage. Cable Tensionometer (Strain Gage) and Pulling Devices Prior to a medium/high voltage cable installation, if cable is being installed in a cable tray or conduit, the specific pulling tensions that will act on the cable and cable pulling equipment throughout the pull are calculated. Based on the maximum cable tensions that are calculated for various pulling directions and cable lengths, a final cable pulling schedule is determined. The proper cables and pulling equipment are then staged at the various pulling points throughout the length of the cable pull. The highest probability for cable damage occurs during the installation process. If the correct cable pulling methods are used, and if the maximum pulling tensions are not exceeded, the cable should be installed without damage to the cable or the cable support system. The purpose of conducting an installation inspection of the cable pulling process is to ensure that the cable pulling methods are correct and that the cable pulling tensions do not exceed the maximum values that were determined during the design phase of the installation. To evaluate the cable pulling process, personnel should visually observe that the correct cable and cable pulling equipment or devices are used in the cable pull through performance of visual checks at both ends of the pull (or pulls). Cable tensiometer (strain gage) checks are performed throughout the pull (or pulls) to ensure that the maximum cable pulling tensions are not exceeded.


24



Point-to-Point Verification of Cables A general procedure to evaluate the strain gage and pulling devices is provided in Work Aid 4. During a cable installation process, the cable is installed along the route that was chosen for the installation. A facility installation can have many different medium/high voltage power cables that are required to be installed, and the cables sometimes share routes (e.g., conduit and cable trays) for engineering and economic reasons. A point-to-point verification of the cable installation is performed before and during the cable installation process to ensure that the correct cable is being installed along the correct route. Because a time lag can exist between the initial design of a cable installation and the actual installation process, the cable route should also be checked during the point-to-point verification. In an industrial facility, plant or system conditions can change over time. The cable route check that is performed during the point-to-point verification can uncover routing problems that may not have existed at the design phase of the cable installation. Additionally, some routing problems may not become clear until the cable is actually being installed. A list of the items that should be included in a point-to-point verification of medium/high voltage cables is provided in Work Aid 4. During the point-to-point verification, the installation of the cable terminations and splices should be inspected. The purpose of performing the evaluation of the medium/high voltage cable terminations and splices is to determine whether the medium/high voltage cables have been correctly terminated or spliced. The main causes of cable failure are damage during installation and improper splices or terminations. An evaluation of cable splices and terminations can uncover problems or installation errors. The identification of problems or errors prior to placing a cable in service can prevent costly repairs or replacements later in the operational life of the cable. To conduct the medium/high voltage cable terminations and splices evaluation, inspection personnel should visually check all terminations and splices during a "walk down" of the installation to ensure that they match the drawings, prints, or specifications for the installation. A list of the items that should be included in the medium/high voltage cable terminations and splices evaluation is provided in Work Aid 4. A general cable termination and splice evaluation procedure is also provided in Work Aid 4.


25



MEDIUM/HIGH VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE The operational testing phase of the commissioning cycle provides an opportunity for Saudi Aramco personnel to perform the following: • •

System source feed compatibility checks Complete system functional test

System source feed compatibility checks are performed on medium/high voltage cables through application of the full system voltage onto the cable. For example, a voltage value of 13.8 kV ac is used for 15 kV cables to be operated at 13.8 kV. With the voltage applied, voltage phasing, synchronizing, device rotation, and other source feed compatibility checks are performed. Parallel or alternate power source feed operations are also performed to ensure the total operation of the major components of the medium/high voltage cable system. A complete system functional test is performed on medium/high voltage cables to ensure that the entire low voltage cable system functions in accordance with the system design. During the complete system functional test of medium/high voltage cables, the cables are allowed to assume a fully-loaded condition for a period of time that is adequate to obtain the maximum system temperature. After the loaded time period, the cable temperatures are monitored. The medium/high voltage cable temperatures can be monitored locally through use of temperature monitoring equipment or through use of thermographic surveys. Particular attention should be paid to splice and termination points during the complete system functional test. Infrared thermography can be used to detect hot spots and abnormal cable temperature conditions.


26



WORK AID 1: UPON RECEIPT

REFERENCES FOR EVALUATING LOW VOLTAGE CABLES

Low Voltage Cable Types Figures 13 through 17 may (although it is not mandatory) be used as a reference to evaluate the low voltage cable types upon receipt of the low voltage cable. Figure 13 provides a list of cables that are used for different applications.

Voltag e Applicatio Class n 600V

Air

Location/Classification

Non-Hazardous Class 1, Div. 2 Class 1, Div. 1

Dry or Wet

Non-Hazardous

Dry or Wet

Class 1, Division 2

Dry or Wet

Non-Hazardous or Class 1, Division 1 or Class 1, Division 2

Dry, Wet or Wet and Oily

Non-Hazardous or Class 1, Division 2

Wet or Wet and Oily

Dry or Wet

Tray

Conduit

Direct Burial

Portable

Class 1, Div .1 or 2 Dry or Wet

Temp No. of . Conductors Ratin g oC MC 90 3/C MI 85 1/C or 3/C MI 85 1/C or 3/C RHH/RHW/US 90/75 1/C E 3/C MC 90 3/C TC 90/75 3/C XPLE/PVC 90 1/C MC 90 3/C TC 90/75 3/C XPLE/PVC 90 1/C RHH/RHW/US 90/75 1/C or 3/C E 90/75 3/C TC 75 1/C THW 90/75 1/C THHN/THWN 85 1/C NYA 90 1/C XPLE/PVC RHH/RHW/US 75 1/C or 3/C E 90 3/C MC 75 3/C TC 90 1/C XPLE/PVC G 90 3/C Cable type

Min./Max. Conductor Size 14-1000 14-4/0 14-4/0 250-1000 14-1000 14-1000 14-1000 2.5-500 mm2 14-1000 14-1000 2.5-500 mm2 14-1000 14-1000 14-1000 14-1000 2.5-500 mm2 2.5-500 mm2 8-1000 14-1000 14-1000 2.5-500 mm2 8-1000

Table of Low Voltage Power Cable Example Applications Guide Figure 13


27



WORK AID 1 (Cont'd) Service Classification * Type A Type B Type C Type D

*

Use

Voltage Rating

Type A are used for supervisory monitoring, data recording, and information transfer. Type B are used for protective devices and general use. Type C are used for connection to circuits with heavy or magnetic trip or break devices. Type D are used in conjunction with high voltage lines.

300 V 600 V 1000 V 5000 V phase-toground

For Saudi Aramco installations, Type A and B service control cables will generally be used. Table of ICEA Control Cable Classifications Figure 14

Signal Levels Size Range Construction Shielding

Electrical 50 VAC - 600 VAC -ordc 10 AWG - 18 AWG (6mm2 - 2.5mm2) Non-paired, concentric lay Not generally required

Electronic Millivolts - 50V -orPulse Milliamperes (60 Hz or higher) 16 AWG - 22 AWG Paired Required on all pairs and overall

Table of Electrical and Electronic Control Cable Applications Figure 15


28



WORK AID 1 (Cont'd)

Low Voltage Cable Terminations and Splices Figure 16 table shows the preferred methods for terminating solid-dielectric cables: Termination Type Premolded terminations

Voltage Rating and Use Indoor terminations up to 35 kV

Heat-shrinkable terminations Elbows (premolded separable insulated connectors) Porcelain dry type (e.g., pothead)

All locations up to 35 kV

Taped terminations

Indoor terminations.

All locations up to 35 kV All locations up to 69 kV

Notes The premolded terminations that are used should be manufactured by Elastimold or meet Elastimold specifications.

Elbow terminations should be manufactured by Elastimold or meet Elastimold specifications. Porcelain dry-type terminations should be manufactured by Joslyn or meet Joslyn specifications. Taped terminations should be manufactured by 3M or meet 3M specifications.

Preferred Methods of Terminating Solid-Dielectric Cables Figure 16


29



WORK AID 1 (Cont'd) Figure 17 shows the recommended cable terminators for types MC, MV, and TC cables that enter enclosures that are in either unclassified or Class 1, Div. 2 areas: Cable Type MC

MV or TC (in conduit)

(1) (2) (3)

Location Wet

Terminator Type(1) OZ SPKHK or equal(2)(3)

Dry Wet

OZ SPKGK or equal(2) OZ CRN or equal(3)

Dry

Direct Entry

In combination with a sealing fitting when sealing is required in Class 1, Division 2 areas. The cable sheath should be extended into the sealing fitting so that the sealing compound surrounds the edge of the cable sheath. Refer to Saudi Aramco Standard Drawing AC-036538. A sealing compound should be used to prevent moisture entry in the cable or conduit. Recommended Cable Terminators for MC, MV, and TC Cable Figure 17

General Procedure to Evaluate Low Voltage Cable Upon Receipt The following general procedure should be used to evaluate low voltage cables upon receipt: 1. Perform a visual inspection of the received cable for manufacturer defects and shipping or transportation damage (e.g., nicks, cuts, and gouges). 2.

Verify the low voltage cable against the installation specification by checking that the following are in compliance with the electrical installation drawings: • • • • •

3.

Voltage rating of the cable Cable ampacity Conductor size (in AWG or KCMIL) Cable construction material

• Cable insulation type Metallic shield, concentric neutral (if one is required), and cable outer jacket

Verify that the low voltage cable is in compliance with the following applicable Saudi Aramco low voltage cable requirements (from SAES-P-104):


30



WORK AID 1 (Cont'd) •

Verify that low voltage wire and cable (600 V or 600/1000 V and below) have a minimum rating of 75_C and comply with ANSI/NFPA 70, IEC 502, or SSA 55. Verify that wire and cable that are manufactured in accordance with IEC 502 or SSA 55 are flame retardant in accordance with IEC 332.

•

Verify that the concentric neutral wire, metallic armor, and metallic sheaths are protected with a PVC or equivalent jacket.

•

Verify that power and control conductors are stranded copper (except that solid copper conductors 6 mm2 (10 AWG) and smaller may be used in non-industrial locations and for specialty applications). Verify that wire or cable stranding is ASTM B 8 Class B or C or IEC-228 Class 2. Verify that all flexible cords, portable cables, and motor leads have finer stranding in accordance with appropriate ICEA and UL Standards or manufacturers' recommendations.

•

Verify that splicing of conductors is kept to a minimum.

•

Verify that conductors of multi-conductor control cables are numbered or color coded by colors other than green, white, or gray.

•

Verify that the minimum size of (power and control) conductors that are rated for 600 V and below is 2.5 mm2 (14 AWG).


31



WORK AID 2: REFERENCES FOR EVALUATING LOW VOLTAGE CABLE INSTALLATION AND TESTING Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables The Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables provides a field installation check list for low voltage cable installations. P-004 has a broad check list of visual and mechanical inspections, as well as the listed electrical tests that are required for low voltage cable installations. Space is also provided on the form for test data.


32



WORK AID 2 (Cont'd) FORM # P-004 (7/94)

SHT 1 of 2

Saudi Aramco Pre-Commissioning Form Low Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings & Documents Manufacturer: Model No.: Serial: Commissioning Date: Field Installation Tests Visual and Mechanical Inspection YES

NO

YES

NO

1. Inspect cables for physical damage and proper connection in accordance with single line diagram. 2. Cable connections shall be torque tested to manufacturer’s recommended values or values recommended in P-000. 3. Verify proper terminals and crimping die are used on cable and that crimping procedure is proper. 4. Verify cable color coding. Electrical Tests 1. Perform Megger Test on each cable with respect to ground and adjacent cables. For cables 250 volt and less use 250 volt megger, for cables 250 volt to 600 volt use 1000 volt megger, for cables above 600 volts and less than 1200 volts use 2500 volt megger. 2. Perform D.C. High Potential Test on cable with respect to ground and adjacent cables. High Potential test cables 250 volt to 1000 volt at 2000 volts.


33



3. Perform continuity test to insure proper cable connection.

NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entries should be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.

SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS

APPROVALS Signature & Date Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables Figure 18


34




SHT 2 of 2

Saudi Aramco Pre-Commissioning Form Low Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings & Documents Manufacturer: Model No.: Serial: Commissioning Date: Field Test Data Cable Ident.

Cable Size

Cable Type

Cable Voltage Rating

Connection

Megger Results Megohms

DC Hipot Results Microamps

A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD A-B, C & GRD B-C, A & GRD C-A, B & GRD


35




SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS

APPROVALS Signature & Date


36



WORK AID 2 (Cont'd) Information, Formulas, and Tables for Use in Evaluating the Results of Insulation Resistance (Megger) Tests Low voltage (600 V and below) cables, including splices to existing cables, must be 500 V dc megger tested after installation (but prior to backfill in the case of direct buried cables) and prior to placing in service. The following are the types of megger tests that can be conducted: • • •

Short time or spot reading Time resistance Dielectric absorption ratio

When the dielectric absorption ratio megger test is performed, the polarization index can be determined through use of the following equation, in which the readings are of resistance: Figure 19 provides insulation conditions for dielectric absorption (60/30) ratio results and polarization index (10/1) ratio results.


37



WORK AID 2 (Cont'd) Insulation Condition Dangerous

60/30 - Second Ratio ----

10/1 - Minute Ratio (Polarization Index) Less than 1

Questionable

1.0 to 1.25

1.0 to 2

Good

1.4 to 1.6

2 to 4

Excellent

Above 1.6

Above 4

Dielectric Absorption Ratio Chart Figure 19 Information, Formulas, and Tables for Use in Evaluating the Results of DC Hi-Pot Tests The dc hi-pot test should be secured if one of the following situation occurs: • • •

The duration of the test has expired A rapid rise in leakage current occurs The polarization index < 1

The following are the characteristics of a satisfactory dc hi-pot test: •

The leakage current gets smaller over time.

•

The polarization index > 1.

• The leakage current increases on a straight line as voltage is increased. No "knee" is noticeable in the leakage current curve. Figure 20 shows a failure forecast table that is used with dc hi-pot test results to predict when a cable failure could occur.


38



WORK AID 2 (Cont'd) ELASTOMERIC (EPR) FAILURE FORECAST FROM DC HIGH POTENTIAL TESTING DC Test Potential at Start of Current Runaway Estimated Failure Time (% of AC rms Voltage) (Years) 200 0.0 300 0.5 500 2.0 800 Over 6 Table of Elastomeric (EPR) Cable Failure Forecast Figure 20


39



WORK AID 2 (Cont'd) An example of dc hi-pot test data is shown in Figure 21. Figure 21 shows both good and bad insulation test data. Use Word 6.0c or later to


Example of DC Hi-Pot Test (Good and Bad Cable Insulation) Figure 21


40



WORK AID 2 (Cont'd) Evaluating the Cable Tensionometer (Strain Gage) and Pulling Devices The following are the inspections and checks that should be performed during the evaluation of the cable tensionometer (strain gage) and pulling devices evaluation: •

Check that the proper cable pulling hardware is provided.

•

Check the actual conduit or cable tray bend radii to ensure conformity to the original pulling tension calculations.

•

Check the cable reel assignments and cutting schedules.

• Check the minimum and maximum pulling specifications (e.g., tensions). •

Check the arrows on the cable reels for the direction to pull the cable off of the reel.

•

Inspect the cable for jacket damage.

•

Ensure that all water and debris are removed from underground conduit prior to the cable pull.

Point-to-Point Verification of Cables The following are the inspections and checks that should be performed during the point-topoint verification of a cable installation: •

Verify that circuit separation is maintained between the cable and any other cables in the run.

•

Verify the clearance between the cable and process piping or other process facilities.

•

If a raceway (e.g., cable tray and conduit) is used for the installation, verify that the cable is correctly installed in the raceway.

•

Verify that the cable supports and fasteners are installed correctly and that there is no cable damage.

•

Spot check the cable installation terminations and splices.


41



WORK AID 2 (Cont'd) Figure 22 shows Saudi Aramco and industry splices and terminations installation requirements. General requirements

Compression-type connectors are the preferred method for splicing or terminating cable conductor ends. Compression (crimped) type connectors must be used for terminating stranded conductors. All compression connectors must be tinned copper, and they must have a manufacturer's reference compression die number and conductor size printed or stamped on the connector. The metallic composition of the crimp connector and the metallic composition of the cable conductor should be similar. The use of solder lugs is prohibited. Cable terminators that rely on inwardly protruding flat springs (tines) for grounding the metallic sheath or armor are prohibited. Armored cable (unless specifically designated as Type AC per NEC Article 333) must be manufactured to IEC 502 and must have galvanized steel wire armor or galvanized double steel tape armor. For installation and application purposes, the cable is considered to be equivalent to type MC (metal clad) cable, except suitable armored cable terminators (glands) must be used to terminate and ground the armor. Type MC cable and armored cable must be permitted to be installed exposed where it is not subject to damage by vehicular traffic or similar hazards. Other types of cable must not be installed exposed above ground, and must be installed in cable trays, conduit, or, where flexibility is required, in flexible conduit. To prevent water from entering the end of the cable, heat shrinkable boots should be placed over the crotch of a three-phase cable and shrunk into place. Lugs for bolting terminations to buswork or equipment should be ordered with NEMA standard spacing (15 mm holes on 45 mm centers). Equipment and buswork termination pads also should be specified with NEMA standard spacing. Cable terminal lugs should be a one hole, two hole NEMA, four hole NEMA, or pin terminal design.

Saudi Aramco and Industry Splices and Terminations Installation Requirements Figure 22


42



WORK AID 2 (Cont'd) Outdoor requirements

Outdoor riser terminations of shielded, solid dielectric cables must have a creepage path to ground of 40 mm (1.5 in) per kV phase to phase and should use either heat-shrinkable termination kits, with skirts or porcelain dry type terminators (Joslyn PSC or equal). If three-conductor cables are used, the cable crotch should be sealed. PILC and VCLC high voltage cable terminations require the use of compound filled potheads or suitable heat-shrinkable terminations. Indoor terminations of shielded, solid-dielectric cable should provide stress relief and should have a minimum creepage path to ground of 25 mm/kV (1 in/kV) phase to phase. Stress relief for indoor shielded, solid-dielectric cables may be provided by stress relieving tape, premolded stress cones, heat shrink stress tubing, or taped cones. Normally all that is required for an enclosed termination is to strip the cable jacket and shield to the designated length, connect (e.g., crimp) a termination lug, and install a stress cone.

Indoor requirements

Saudi Aramco and Industry Splices and Terminations Installation Requirements Figure 22 (Cont'd) The following is a general terminations and splices visual inspection/evaluation procedure for low voltage cable installations: 1.

The inspection personnel should verify that none of the following are present: •

Wrap-around, rigid snap-on, or adhesive-type markers to identify wiring at terminal blocks.

•

Solder lugs.

•

Twist-on connectors (wirenuts).

•

Cable terminators that rely on inwardly-protruding flat springs (tines) for grounding the metallic sheath or armor.


43



WORK AID 2 (Cont'd) 2.

The inspection personnel should check that the terminations are one of the Saudi Aramco preferred methods.

3.

The inspection personnel should check that the terminators that are used for the installation are one of the recommended types.

4.

The inspection personnel should check the installation against the splices and terminations installation requirements that are shown in Figure 22.

The following is an excerpt from GI 2.710, New Construction Check List Example, that illustrates the overall check list and sign-off for major pieces of electrical equipment. 3.

Electrical Equipment All substations, power cable, electrical equipment, Construction Agency including lighting and wiring, to be checked for proper application, operation, and grounds. Distribution panels, switches properly identified, and all energization certificate requests signed. Power Distribution Dept. Project Inspection Commissioning (Note 1)


44



WORK AID 2 (Cont'd) Figure 23 shows an excerpt from GI 2.710, General Instruction Manual, that illustrates the inspections and tests that should be performed on major pieces of electrical equipment prior to the turnover of a facility.

DIVISION OF RESPONSIBILITIES FOR TURNOVER MECHANICAL COMPLETION (Pre-Turnover)

1. 2. 3. 4. 5. 6. 7. 8. 9.

General Civil/Structural Electrical Piping Mechanical Equipment Fire & Safety Systems Communications Instrumentation Catalyst, Chemical and Dessicants

X R W I O E&I M P PDD FP LP P&CSD CC&OS

-

SUPPLEMENT NO. 2.710-6 STARTUP (Post-MCC) Commissioning with Constr. Agency (Note 2) Proponent

Project Operations/ Inspection Commissioning Perform Work Review and Approve Witness (Event) Inspect (Work) Operate Process Equipment - By Operator Maintenance’s Start-Up Electrical & Instrument Specialist Maintenance’s Start-Up Machinist Maintenance’s Start-Up Fitter Power Distribution Department Fire Prevention Loss Prevention Process & Control Systems Department Computer, Communications and Office Systems

NOTE 1: Construction Agency is responsible for performing all work prior to Mechanical Completion, unless assigned otherwise as indicated with an X. NOTE 2: Per paragraph 4.3.1.6 of G.I.2.710, Construction Agency will provide an agreed number of Contractor Commissioning Assistance Personnel to work under the direction of the Proponent Commissioning Supervisor or his Nominee. Alternatively, and as directed by Proponent, Operations/Commissioning will utilize E&I, P or PDD personnel for Commissioning Assistance. NOTE 3: PDD will inspect and sign-off for all Power Distribution Systems above 480V; 480V and below will be inspected by Project Inspection and witnessed by Operations/Commissioning. NOTE 4: Minimum of 10% of Megger Testing to be witnessed, balance to be monitored. NOTE 5: Routine cleaning/flushing to be witnessed by Inspection and reviewed by Commissioning. All other specialty cleaning (lube oil systems, etc.) to be witnessed by Commissioning.

GI 2.710 Excerpt Figure 23


45



WORK AID 2 (Cont'd) DIVISION OF RESPONSIBILITIES FOR TURNOVER MECHANICAL COMPLETION (Pre-Turnover) Project Inspection


Operations/ Commissioning


46



3. ELECTRICAL a. Perform dielectric strength tests on power transformer and disconnect switch insulating oil and install when satisfactory.

I

b. Check condition of grease in grease lubricated motor and generator bearings.

PDD-W

I

c. Perform all necessary prestart-up non-operating tests and Hi Pot checks on all power cables, generators, Switchgear, MCCs, transformers and grounding resistors following manufacturers’ instructions and guidelines given in the applicable Saudi Aramco Pre-Commissioning Forms Manual available from Consulting Services Department.

I

PDD/W (Note 3)

d. Measure and record the insulation resistance (Megger Testing) of all power (480 V or less), instrument wiring (including thermocouple leads) and lighting circuits from conductor to conductor and from each conductor to ground.

I (Note 4)

R

e. Perform applicable checks, adjustments and field tests using, if necessary in order to maintain schedule, temporary construction power.

I

R PDD/W (Note 2)

f. Calibrate and set substation relays on all circuit breakers. Set time delays. Set and test fault pressure relays and transformer taps.

I

PDD/W

g. Energize substations and load centers by connection to electrical distribution systems (Energized by authorized electrical systems operator after obtaining approved “Energization Authorization Certificate”). h. Check operability of emergency and instrument power systems as well as emergency lighting system.

PDD/W

I

i. Issue work permits to Contractor for carrying out checks on electrical equipment, after facilities are energized per item (g) if partial MCC signed. j. Paint or tag all electrical apparatus (Push button boxes, connection boxes, etc) according to Saudi Aramco’s color code or regulations.

W

R

I

X

R

k. Construction Agency will use existing established work permit procedure for remaining construction period, once electrical equipment is energized. (If the existing Tag and Lock-Out Procedure needs to be revised, it shall be approved by Loss Prevention and implemented as part of this effort). l. Perform a final functional checkout for all equipment and systems.


X

X PDD/W

O-I

47



GI 2.710 Excerpt Figure 23 (Cont'd)


48



WORK AID 3:REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGE CABLES UPON RECEIPT Medium/High Voltage Cable Types Figures 24 through 26 may (although it is not mandatory) be used as a reference to evaluate the medium/high voltage cable types upon receipt of the medium/high voltage cable. Figure 24 provides a list of cables that are used for different applications.

Voltage Class Application 5000V

Conduit Direct Burial Air Tray

Portable 15,000V Conduit Direct Burial Air Tray

Portable 35,000V Conduit Direct Burial Air Tray

Non-Hazardous or Class 1, Div. 1 or 2 Non-Hazardous or Class 1, Division 2 Non-Hazardous or Class 1, Division 2 Non-Hazardous

Dry, Wet or Wet and Oily Wet or Wet and Oily Dry or Wet

MV

Temp. No. of Min./Max. Rating Conductors Conductor Size oC 90 1/C or 3/C 8-1000

MC MV MC

90 90 90

3/C 1/C or 3/C 3/C

8-1000 8-1000 8-1000

Dry or Wet

MC MV

90 90

Class 1, Division 2

Dry or Wet

MC MV

90 90

Class 1, Div. 1 or 2 Non-Hazardous or Class 1, Div. 1 or 2 Non-Hazardous or Class 1, Division 2

Dry or Wet Dry, Wet or Wet and Oily Wet or Wet and Oily

90 90 90 90 90

Non-Hazardous or Class 1, Division 2 Non-Hazardous

Dry or Wet

SHD MV URD MC MV URD MC

3/C 1/C 3/C 3/C 1/C 3/C 3/C 1/C or 3/C 1/C 3/C 1/C or 3/C

90

3/C

8-1000 250-1000 8-1000 8-1000 250-1000 8-1000 8-1000 2-1000 8-1000 2-1000 2-1000 8-1000 2-1000

MC MV

90 90

Class 1, Division 2

Dry or Wet

URD MC MV

90 90 90

Class 1, Div. 1 or 2 Non-Hazardous or Class 1, Div. 1 or 2 Non-Hazardous or Class 1, Division 2

Dry or Wet Dry, Wet or Wet and Oily Wet or Wet and Oily

Non-Hazardous or Class 1, Division 2 Non-Hazardous or Class 1, Division 2

Dry or Wet

SHD MV URD MV MC URD MC

90 90 90 90 90 90 90

3/C 3/C 1/C 1/C 3/C 3/C 1/C 3/C 1/C 1C 1C 3/C 1/C 3/C

2-1000 2-1000 250-1000 8-1000 2-1000 2-1000 250-1000 2-1000 1/0-1000 8-1000 1/0-1000 1/0-1000 8-1000 1/0-1000

MV MC URD

90 90 90

1/C 3/C 1/C

1/0-1000 1/0-1000 8-1000

Location/Classification


Dry or Wet

Dry or Wet

Cable type

49



69,000V Cond., Dir. Non-Hazardous or Burial Class 1, Division 2

Dry, Wet or EPR/XLPE Wet and Oily

90

1/C

4/0-1000

Table of Medium/High Voltage Power Cable Example Applications Guide Figure 24


50



WORK AID 3 (Cont'd)

Medium/High Voltage Cable Terminations and Splices Figure 25 shows the preferred methods for terminating solid-dielectric cables: Termination Type Premolded terminations

Voltage Rating and Use Indoor terminations up to 35 kV

Heat-shrinkable terminations Elbows (premolded separable insulated connectors) Porcelain dry type (e.g., pothead)

All locations up to 69 kV

Taped terminations

Indoor terminations

All locations up to 35 kV All locations up to 69 kV

Notes The premolded terminations that are used should be manufactured by Elastimold or meet Elastimold specifications. Example: Elastimold or equal. Elbow terminations should be manufactured by Elastimold or meet Elastimold specifications. Porcelain dry-type terminations should be manufactured by Joslyn or meet Joslyn specifications. Taped terminations should be manufactured by 3M or meet 3M specifications.

Preferred Methods of Terminating Solid-Dielectric Cables Figure 25


51



WORK AID 3 (Cont'd) Figure 26 shows the recommended cable terminators for types MC, MV, and TC cables entering enclosures that are in either unclassified or Class 1, Div. 2 areas: Cable Type MC

MV or TC (in conduit)

(1) (2) (3)

Location Wet

Terminator Type(1) OZ SPKHK or equal(2)(3)

Dry Wet

OZ SPKGK or equal(2) OZ CRN or equal(3)

Dry

Direct Entry

In combination with a sealing fitting when sealing is required in Class 1, Division 2 areas. The cable sheath should be extended into the sealing fitting so that the sealing compound surrounds the edge of the cable sheath. Refer to Saudi Aramco Standard Drawing AC-036538. A sealing compound should be used to prevent moisture entry in the cable or conduit. Recommended Cable Terminators for MC, MV, and TC Cable Figure 26

General Procedure to Evaluate Medium/High Voltage Cable Upon Receipt The following general procedure should be used to evaluate medium/high voltage cables upon receipt: 1.

Perform a visual inspection of the received cable for manufacturer defects and shipping or transportation damage (e.g., nicks, cuts, gouges).

2.

Verify the medium/high voltage cable against the installation specification by checking that the following are in compliance with the electrical installation drawings: • • •


Voltage rating of the cable Cable ampacity Conductor size (in AWG or KCMIL)

52



WORK AID 3 (Cont'd) • • • 3.

Cable construction material Cable insulation type Metallic shield, concentric neutral (if one is required), and cable outer jacket

Verify that the medium/high voltage cable is in compliance with the following applicable Saudi Aramco cable requirements (from SAES-P-104): •

Verify that medium voltage power cable, 5 kV through 35 kV, (excluding submarine, submersible pump (down hole), portable, and motor lead cable) complies with 15-SAMSS-502.

•

Verify that concentric neutral wire, metallic armor, and metallic sheaths are protected with a PVC or equivalent jacket.

•

Verify that the minimum size of conductors are as follows: -

•

5 kV: 10 mm2 (8 AWG) 15 kV: 35 mm2 (2 AWG) 35 kV: 50 mm2 (1/0 AWG) 69 kV: 120 mm2 (4/0 AWG)

The splicing of conductors must be kept to a minimum. A maximum of two splices must be permitted in any one circuit for new installations of cables that are rated above 1,000 V. Splices and terminations on cables that are rated above 1,000 V must be made by personnel who are certified in accordance with Saudi Aramco General Instruction 2.705.


53



WORK AID 4: REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGE CABLE INSTALLATION AND TESTING

Saudi Aramco Pre-Commissioning Forms, P-005 and P-006, Medium and High Voltage Cables The Saudi Aramco Pre-Commissioning Forms, P-005, and P-006, Medium and High Voltage Cables (Figures 27 and 28), respectively, provide a field installation check list for medium and high voltage cable installations. The pre-commissioning form has a broad check list of visual and mechanical inspections, as well as the listed electrical tests that are required for medium and high voltage cable installations. Space is also provided on the form for test data.


54




SHT 1 of 4

Saudi Aramco Pre-Commissioning Form Medium Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Field Installation Checklist Visual and Mechanical Inspection YES

NO

1. Check cable reel assignments and cutting schedules. 2. Check cable pulling schedule for direction of pull and method of pulling in conduit for medium voltage cable. 3. Check arrows on cable reels for direction for pulling off reel. 4. Check for correct cable test voltages, minimum pulling temperature and type of pulling compound. 5. Inspect cables for jacket damage. 6. The conductors are identified as per specification and drawings. 7. Cable ends sealed after cutting. 8. All water and debris must be removed from underground conduit before pulling cable. 9. Cable supports and spacing as per specifications and drawings. 10. Cable supports are adjacent to terminal fittings.


55



11. Conduits clean, stub-ups protected, open ends plugged, damage during construction repaired. 12. Field bend radius correct per specification and codes. Bends free of deformities. 13. Expansion joints as shown on drawings. NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entries should be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.

SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS

APPROVALS Signature & Date Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage Cables Figure 27


56




SHT 2 of 4

Saudi Aramco Pre-Commissioning Form Medium Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Visual and Mechanical Inspection (Continued) YES

NO

YES

NO

14. Spacing between instrument and power conduit and/or cables as per specifications. 15. Spacing from hot pipes and from hot surfaces maintained. 16. Proper fittings are installed with threads fully engaged, proper sealing compound is used, there are no wrench cuts, conduit ends have bushings and covers installed. 17. Seals and drains are installed per drawings. 18. Aluminum, PVC or PVC coated conduits are installed where specified on drawings. 19. Flexible conduit is installed with proper bending radius and with standard fittings. 20. Metal junction boxes leveled and supported per drawings with proper hubs, locknuts and bushings installed. 21. Seals poured. Electrical Test 1. Cables on reels must be isolated and meggered before unreeling.


57



2. Prepare installed cables for test by ensuring the circuit is de-energized, remove any temporary grounds and disconnect cable from equipment. If equipment cannot be disconnected, a reduced voltage should be used for the test.


SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS

APPROVALS Signature & Date Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage Cables Figure 27 (Cont'd)


58




SHT 3 of 4

Saudi Aramco Pre-Commissioning Form Medium Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Electrical Test (Continued) YES

NO

3. Insulate cable cores from ground.

4. Erect safety barriers and post safety man at cable end remote from the test equipment. 5. Check the insulation resistance of the cable using a megger tester. The test voltage should be 5000 volts for 5000 volt and above cables. Measure the insulation resistance of each core and any metallic armor or sheath grounded at one end only. 6. Each cable shall be high potential tested as follows: each core to ground, with the shield, other cores and any metallic armor or sheath grounded at one end only. 7. For commissioning new cables, the final D.C. test voltage is the 80% test voltage in the tables below.


59



8. For commissioning new cables that are spliced to old cables, and for testing old cables, the final D.C. test voltage shall be determined by the proponent of the cables, and should not exceed the 65% test voltage in the tables below (40% of these values is recommended after 5 years). A voltage equal to 2X operating voltage + 2 kV is recommended for extremely old cables with low megger readings. 9. The D.C. high voltage shall be applied in a minimum of four steps (each step approximately equal to the rated rms voltage of the cable) of one (1) minute duration each except for the final test voltage which shall be maintained for fifteen (15) minutes.


SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS


Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage Cables Figure 27 (Cont'd)


60




SHT 4 of 4

Saudi Aramco Pre-Commissioning Form Medium Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Electrical Test (Continued) YES

NO

10. On completion of tests the cable shall be left with all cores and shields grounded for one hour to allow the residual charge to dissipate. XLPE OR EPR CABLES MANUFACTURED TO AEIC CS5 OR CS6 AND 15-SAMSS-502 Rated Voltage 5 kV 15 kV 35 kV

Insulation Thick. 115 Mils 220 Mils 345 Mils

80% Test Voltage 36 kV 64 kV 100 kV



XLPE OR EPR CABLES MANUFACTURED TO IEC-502 AND 15-SAMSS-502 Rated Voltage Insulation 80% Test 65% Test 40% Test Thick. Voltage Voltage Voltage 6/10 kV 3.4 MM 37 kV DC 29 kV DC 18.5 kV 12/20 kV 5.5 MM 64 kV DC 52 kV DC 32 kV


61



NOTES: 80% and 65% refer to percentages of the factory test voltages specified in AEIC CS5 and CS6. AEIC CS5 and CS6 permit testing at the 65% test voltage “at anytime during the period of the guarantee.” Test values for cables older than 5 years are listed in the 40% column.


SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS

APPROVALS Signature & Date Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage Cables Figure 27 (Cont'd)


62




SHT 1 of 4

Saudi Aramco Pre-Commissioning Form High Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Field Installation Checklist Visual and Mechanical Inspection YES

NO

1. Check cable reel assignments and cutting schedules. 2. Check cable pulling schedule for direction of pull and method of pulling. 3. Check arrows on high voltage cable reels for direction for pulling off reel. 4. Check for correct cable test voltages, minimum pulling temperature and type of pulling compound if applicable. 5. Inspect cables for jacket damage. 6. The conductors are identified as per specification and drawings. 7. Cable ends sealed after cutting. 8. Cable support and spacing as per specifications and drawings. 9. Cable supports are adjacent to terminal fittings. 10. Field bend radius correct per specification and codes. Bends free of deformities. 11. Expansion joints as shown on drawings.


63



12. Spacing between instrument and power conduit and/or cables as per specifications. 13. Spacing from hot pipes and from hot surfaces maintained.


SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS


Saudi Aramco Pre-Commissioning Form, P-006, High Voltage Cables Figure 28


64




SHT 2 of 4

Saudi Aramco Pre-Commissioning Form High Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Visual and Mechanical Inspection (Continued) YES

NO

YES

NO

14. Proper fittings are installed with threads fully engaged, proper sealing compound is used, there are no wrench cuts, conduit ends have bushings and covers installed. 15. Seals and drains are installed per drawings. 16. Aluminum, PVC or PVC coated conduits are installed where specified on drawings. 17. Metal junction boxes leveled and supported per drawings with proper hubs, locknuts and bushings installed. 18. Seals poured.

Electrical Tests 1. Cables on reels must be isolated and meggered before unreeling. 2. Prepare installed cables for test by ensuring the circuit is deenergized, remove any temporary grounds and disconnect cable from equipment. 3. Insulate cable cores from ground. 4. Erect safety barriers and post safety man at cable end remote from the test equipment. 5. Check the insulation resistance of the cable using a megger tester. The test voltage should be 5000 volts. Measure the insulation resistance of each core and any metallic armor or sheath grounded at one end only.


65



6. Each cable shall be high potential tested as follows: each core to ground, with the shield, other cores and any metallic armor or sheath grounded at one end only. NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entries should be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.

SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS


Saudi Aramco Pre-Commissioning Form, P-006, High Voltage Cables Figure 28 (Cont'd)


66




SHT 3 of 4

Saudi Aramco Pre-Commissioning Form High Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: Electrical Tests (Continued) YES

NO

7. For commissioning new cables, the final D.C. test voltage is the 80% test voltage in the tables below. 8. For commissioning new cables that are spliced to old cables, and for testing old cables, the final D.C. test voltage shall be determined by the proponent of the cables, and should not exceed the 65% test voltage in the tables below (40% of these values is recommended after 5 years). A voltage equal to 2X operating voltage + 2 kV is recommended for very old cables with low megger readings. 9. The D.C. high voltage shall be applied such that the rate of increase of the test voltages should be approximately uniform and should be no more than 100 percent in 10 second nor less than 100 percent in 60 seconds. The final (max) test voltage shall be held for fifteen (15) minutes. 10. On completion of tests the cable shall be left with all cores and shields grounded for one hour to allow the residual charge to dissipate. D.C. TEST VOLTAGES - EPR AND XLPE CABLES (ICEA/AEIC TESTS) Cable Insulation Thickness Max. D.C. Test Voltage (kV) Rating (kV) MM/Mils 100% 80% 75% 69 EPR 16.51/650 240 192 180 69 XLP 16.51/650 240 192 180 115 20.32/800 300 240 225


65% 156 156 195

67



NOTE: At any time during installation, a dc proof test may be made at a voltage not exceeding 75% of the dc test voltage specified in the above table applied for 5 consecutive minutes. After installation and before the cable is placed in regular service, a high voltage dc test may be made at 80% of the dc test voltage specified for fifteen consecutive minutes. The cable may be tested after placing in service any time within the first 5 years at 65% of the dc test voltage. Very old cables are tested at 1/2 the 80% values. NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entries should be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.

SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS




68




SHT 4 of 4

Saudi Aramco Pre-Commissioning Form High Voltage Cables Equipment Type: User Reference: Equipment No.: Description: BI/JO NO.: Plant No./Location Ref. Drawings: & Documents Manufacturer: Model No.: Serial: Commissioning Date: HIGH VOLTAGE CABLE TEST RECORD B.I. or W.O. No. Cable No. Voltage Rating Plant Size & Type High Potential Test (D.C.) Phase 1 to Phase 2 to Phase 3 to Resistance Test Test Voltage - GND GND GND (Megger) and Current Current Current Hold Time Micro Amps Micro Amps Micro Amps Phase Megohms kV Phase 1 to 2 kV Phase 2 to 3 kV Phase 3 to 1 kV Phase 1 to G kV Phase 2 to G kV Phase 3 to G 15 Sec Test Voltage (Megger) 30 Sec 500/1000/2500/5000 Volt 45 Sec 1 Min General Data: 2 Min 3 Min Temp.Deg.F/ C 4 Min % Rel. Hum. 5 Min Insul Thick. 6 Min Cable Test 7 Min Voltage 8 Min 9 Min 10 Min 11 Min 12 Min 13 Min Saudi Aramco DeskTop Standards

69



14 Min 15 Min NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entries should be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.

SAPMT

INSPECTION

OTHER DEPT.

OPERATIONS




70



WORK AID 4 (Cont'd) Information, Formulas, and Tables for Use in Evaluating the Results of Insulation Resistance (Megger) Tests Medium/High Voltage cables (5 kV and above) must be tested as follows: (a)

New installations of cable and splices must be 5 kV insulation resistance (megger) tested after installation. The 5 kV megger must be performed prior to commissioning but prior to backfill in the case of direct buried cables.

(b)

New cables to be spliced to existing cables must be megger tested prior to splicing as in (a) above. After splicing (but prior to backfill in the case of direct buried cables), the new and existing cable combination must be 5 kV megger tested.

The integrity of the overall sheath or jacket of cables that are rated 35 kV and higher must be tested by conducting a 5 kV megger test between the cable insulation metallic shield and ground. Direct buried cables must be tested and accepted prior to backfill of the cable trench. The results of all commissioning megger tests that are performed on cable that is rated 5 kV and above must be documented on the appropriate Saudi Aramco pre-commissioning form. The following are the types of megger tests that can be conducted: • • •

Short time or spot reading Time resistance Dielectric Absorption Ratio

When the dielectric absorption ratio megger test is performed, the polarization index can be determined through use of the following equation, which provides readings of resistance: Figure 29 provides insulation conditions for 60/30 second ratio results and for 10/1 minute ratio results.


71



WORK AID 4 (Cont'd) Insulation Condition Dangerous

60/30 - Second Ratio ----

10/1 - Minute Ratio (Polarization Index) Less than 1

Questionable

1.0 to 1.25

1.0 to 2

Good

1.4 to 1.6

2 to 4

Excellent

Above 1.6

Above 4

Dielectric Absorption Ratio Chart Figure 29 Information, Formulas, and Tables for Use in Evaluating the Results of DC Hi-Pot Tests Medium/High Voltage cables (5 kV and above) must be dc hi-pot tested as follows: (a)

New installations of cable and splices must be dc hi-pot tested after installation. The dc hi-pot test should be conducted after the megger test. The dc hi-pot test must be performed prior to commissioning but prior to backfill in the case of direct buried cables. The voltage levels of the dc hi-pot test are specified in 15-SAMSS-502 and 15-SAMSS-503.

(b)

New cables to be spliced to existing cables must be dc hi-pot tested prior to splicing as in (a) above. After splicing (but prior to backfill in the case of direct buried cables), the new and existing cable combination may be dc hi-pot tested. The dc hi-pot test voltage should be equal to or lower than the values specified under (c) below, as determined by the Proponent of the cable.

c)

Maximum dc hi-pot test voltages for old cables: • standards. • standards.


Cables up to 5 years old: 65% values, applicable AEIC Cables above 5 years old: 40% values, applicable AEIC

72



WORK AID 4 (Cont'd) The results of all dc hi-pot tests that are performed for commissioning on cable that is rated 5 kV and above must be documented on the appropriate Saudi Aramco pre-commissioning form. The dc hi-pot test should be secured if one of the following situation occurs: • • •

The duration of the test has expired A rapid rise in leakage current occurs The polarization index < 1

The following are the characteristics of a satisfactory dc hi-pot test: •

The leakage current gets smaller over time.

•

The polarization index > 1.

• The leakage current increases on a straight line as voltage is increased. No "knee" is noticeable in the leakage current curve. Figure 30 shows a failure forecast table that is used with dc hi-pot test results to predict when a cable failure could occur. ELASTOMERIC (EPR) FAILURE FORECAST FROM DC HIGH POTENTIAL TESTING DC Test Potential at Start of Current Runaway Estimated Failure Time (% of AC rms Voltage) (Years) 200 0.0 300 0.5 500 2.0 800 Over 6 Table of Elastomeric (EPR) Cable Failure Forecast Figure 30


73



WORK AID 4 (Cont'd) An example of dc hi-pot test data is shown in Figure 31. Figure 31 shows both good and bad insulation test data.

Use Word 6.0c or later to


Example of DC Hi-Pot Test (Good and Bad Cable Insulation) Figure 31


74



WORK AID 4 (Cont'd) Evaluating the Cable Tensionometer (Strain Gage) and Pulling Devices The following are the inspections and checks that should be performed during the evaluation of the cable tensionometer (strain gage) and pulling devices evaluation: •

Check that the proper cable pulling hardware is provided.

•

Check the actual conduit or cable tray bend radii to ensure conformity to the original pulling tension calculations.

•

Check the cable reel assignments and cutting schedules.

• Check the minimum and maximum pulling specifications (e.g., tensions). •

Check the arrows on the cable reels for the direction to pull the cable off of the reel.

•

Inspect the cable for jacket damage.

•

Ensure that all water and debris are removed from underground conduit prior to the cable pull.

Point-to-Point Verification of Cables The following are the inspections and checks that should be performed during the point-topoint verification of a cable installation: •

Verify that circuit separation is maintained between the cable and any other cables in the run.

•

Verify the clearance between the cable and process piping or other process facilities.

•

If a raceway (e.g., cable tray or conduit) is used for the installation, verify that the cable is correctly installed in the raceway.

•

Verify that the cable supports and fasteners are installed correctly and that there is no cable damage.

•

Spot check the cable installation terminations and splices.


75



WORK AID 4 (Cont'd) Figure 32 shows Saudi Aramco and industry splices and terminations installation requirements. General requirements

Compression-type connectors are the preferred method for splicing or terminating cable conductor ends. Compression (crimped) type connectors must be used for terminating stranded conductors. All compression connectors must be tinned copper and must have a manufacturer's reference compression die number and conductor size printed or stamped on the connector. The metallic composition of the crimp connector and the metallic composition of the cable conductor should be similar. The use of solder lugs is prohibited. Cable terminators that rely on inwardly protruding flat springs (tines) for grounding the metallic sheath or armor are prohibited. Armored cable (unless specifically designated as Type AC per NEC Article 333) must be manufactured to IEC 502 and must have galvanized steel wire armor or galvanized double steel tape armor. For installation and application purposes, the cable is considered to be equivalent to type MC (metal clad) cable, except suitable armored cable terminators (glands) must be used to terminate and ground the armor. Type MC cable and armored cable must be permitted to be installed exposed where it is not subject to damage by vehicular traffic or similar hazards. Other types of cable must not be installed exposed above ground, and must be installed in cable trays, conduit, or, where flexibility is required, in flexible conduit. To prevent water from entering the end of the cable, heat shrinkable boots should be placed over the crotch of a three-phase cable and shrunk into place. Lugs for bolting terminations to buswork or equipment should be ordered with NEMA standard spacing (15 mm holes on 45 mm centers). Equipment and buswork termination pads also should be specified with NEMA standard spacing. Cable terminal lugs should be a one hole, two hole NEMA, four hole NEMA, or pin terminal design.

Saudi Aramco and Industry Splices and Terminations Installation Requirements Figure 32


76



WORK AID 4 (Cont'd)

Outdoor requirements

Indoor requirements

Outdoor riser terminations of shielded, solid dielectric cables must have a creepage path to ground of 40 mm (1.5 in) per kV phase to phase and should use either heat-shrinkable termination kits, with skirts or porcelain dry-type terminators (Joslyn PSC or equal). If three-conductor cables are used, the cable crotch should be sealed. PILC and VCLC high voltage cable terminations require the use of compound filled potheads or suitable heat-shrinkable terminations. Indoor terminations of shielded, solid-dielectric cable should provide stress relief and should have a minimum creepage path to ground of 25 mm/kV (1 in/kV) phase to phase. Stress relief for indoor shielded, solid-dielectric cables may be provided by stress relieving tape, premolded stress cones, heat shrink stress tubing, or taped cones. Normally all that is required for an enclosed termination is to strip the cable jacket and shield to the designated length, connect (e.g., crimp) a termination lug, and install a stress cone. Indoor HV shielded terminations that are exposed to atmospheric contamination and moisture condensation should be treated as outdoor terminations. Non-porcelain slip-on terminations are allowed, however, providing a creepage path to ground of 33 mm/kV (1.3 in/kV) phase to phase is provided. Such terminators should provide several skirts to increase the creepage path. If at all possible all exposed live parts should be insulated with track resistant tape (3M or equal) or track resistant heat shrinkable tubing (Raychem or equal).

Saudi Aramco and Industry Splices and Terminations Installation Requirements Figure 32 (Cont'd) General Procedure to Evaluate Medium/High Voltage Cable Terminations and Splices The following is a general terminations and splices visual inspection/evaluation procedure for medium/high voltage cable installations:


77



WORK AID 4 (Cont'd) 1.

The inspection personnel should verify that none of the following are present: •

Wrap-around, rigid snap-on, or adhesive-type markers to identify wiring at terminal blocks.

•

Solder lugs.

•

Twist-on connectors (wirenuts).

•

Cable terminators that rely on inwardly-protruding flat springs (tines) for grounding the metallic sheath or armor.

2.

The inspection personnel should check that the terminations are one of the preferred methods.

3.

The inspection personnel should check that the terminators that are used for the installation are one of the recommended types.

4.

The inspection personnel should check the installation against the splices and terminations installation requirements that are shown in Figure 32.

The following is an excerpt from GI 2.710, New Construction Check List Example, that illustrates the overall checklist and sign-off for major pieces of electrical equipment. 3.

Electrical Equipment All substations, power cable, electrical equipment, including lighting and wiring, to be checked for proper application, operation, and grounds. Distribution panels, switches properly identified, and all energization certificate requests signed.

Construction Agency

Power Distribution Dept. Project Inspection Commissioning (Note 1)


78



WORK AID 4 (Cont'd) Figure 33 shows an excerpt from GI 2.710, General Instruction Manual, that illustrates the inspections and tests that should be performed on major pieces of electrical equipment prior to the turnover of a facility.


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WORK AID 4 (Cont'd)

DIVISION OF RESPONSIBILITIES FOR TURNOVER MECHANICAL COMPLETION (Pre-Turnover)

1. 2. 3. 4. 5. 6. 7. 8. 9.

General Civil/Structural Electrical Piping Mechanical Equipment Fire & Safety Systems Communications Instrumentation Catalyst, Chemical and Dessicants

X R W I O E&I M P PDD FP LP P&CSD CC&OS

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Project Operations/ Inspection Commissioning Perform Work Review and Approve Witness (Event) Inspect (Work) Operate Process Equipment - By Operator Maintenance’s Start-Up Electrical & Instrument Specialist Maintenance’s Start-Up Machinist Maintenance’s Start-Up Fitter Power Distribution Department Fire Prevention Loss Prevention Process & Control Systems Department Computer, Communications and Office Systems

NOTE 1: Construction Agency is responsible for performing all work prior to Mechanical Completion, unless assigned otherwise as indicated with an X. NOTE 2: Per paragraph 4.3.1.6 of G.I.2.710, Construction Agency will provide an agreed number of Contractor Commissioning Assistance Personnel to work under the direction of the Proponent Commissioning Supervisor or his Nominee. Alternatively, and as directed by Proponent, Operations/Commissioning will utilize E&I, P or PDD personnel for Commissioning Assistance. NOTE 3: PDD will inspect and sign-off for all Power Distribution Systems above 480V; 480V and below will be inspected by Project Inspection and witnessed by Operations/Commissioning. NOTE 4: Minimum of 10% of Megger Testing to be witnessed, balance to be monitored. NOTE 5: Routine cleaning/flushing to be witnessed by Inspection and reviewed by Commissioning. All other specialty cleaning (lube oil systems, etc.) to be witnessed by Commissioning.

GI 2.710 Excerpt Figure 33


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WORK AID 4 (Cont'd)

DIVISION OF RESPONSIBILITIES FOR TURNOVER MECHANICAL COMPLETION (Pre-Turnover) Project Inspection


Operations/ Commissioning


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3. ELECTRICAL a. Perform dielectric strength tests on power transformer and disconnect switch insulating oil and install when satisfactory.

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b. Check condition of grease in grease lubricated motor and generator bearings.

PDD-W

I

c. Perform all necessary prestart-up non-operating tests and Hi Pot checks on all power cables, generators, Switchgear, MCCs, transformers and grounding resistors following manufacturers’ instructions and guidelines given in the applicable Saudi Aramco Pre-Commissioning Forms Manual available from Consulting Services Department.

I

PDD/W (Note 3)

d. Measure and record the insulation resistance (Megger Testing) of all power (480 V or less), instrument wiring (including thermocouple leads) and lighting circuits from conductor to conductor and from each conductor to ground.

I (Note 4)

R

e. Perform applicable checks, adjustments and field tests using, if necessary in order to maintain schedule, temporary construction power.

I

R PDD/W (Note 2)

f. Calibrate and set substation relays on all circuit breakers. Set time delays. Set and test fault pressure relays and transformer taps.

I

PDD/W

g. Energize substations and load centers by connection to electrical distribution systems (Energized by authorized electrical systems operator after obtaining approved “Energization Authorization Certificate”). h. Check operability of emergency and instrument power systems as well as emergency lighting system.

PDD/W

I

i. Issue work permits to Contractor for carrying out checks on electrical equipment, after facilities are energized per item (g) if partial MCC signed. j. Paint or tag all electrical apparatus (Push button boxes, connection boxes, etc) according to Saudi Aramco’s color code or regulations.

W

R

I

X

R

k. Construction Agency will use existing established work permit procedure for remaining construction period, once electrical equipment is energized. (If the existing Tag and Lock-Out Procedure needs to be revised, it shall be approved by Loss Prevention and implemented as part of this effort). l. Perform a final functional checkout for all equipment and systems.


X

X PDD/W

O-I

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GI 2.710 Excerpt Figure 33 (Cont'd)


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GLOSSARY cable jacket

A protective covering over the insulation of a conductor

cable splice

The physical connection of two or more conductors to provide electrical continuity.

cable termination

A device that seals the end of a cable and that provides an electrical connection to the rest of the electric power system.

circular mil

A unit of measure that is equal to the area of a circle that has a diameter of one mil.

creepage

The shortest distance between two conducting parts measured along the surface or joints of the insulating material between them.

crimp barrel

The cylindrical portion of a crimp connector to which the mechanical force of deformation is applied. The deformation maintains the electrical connection.

dielectric strength

The electrical potential (voltage) gradient at which electrical failure or breakdown occurs.

Elastimold

A company that manufactures splice and termination material that is used in Saudi Aramco.

EPR

Ethylene Propylene Rubber.

grounding eye

The part of a prefabricated mechanical splice that interconnects the shields of the two cables and that forms an effective ground for the splice.

half lapped

A tape configuration in which half of the layer of the tape that is being applied overlaps the layer that was just applied by one-half of its width.

IEC

International Electrotechnical Commission

IEEE

The Institute of Electrical and Electronics Engineers

insulation resistance

The electrical resistance between two conductors that are separated by an insulating material.


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insulator

A device that has high electrical resistance and that is used for supporting or separating conductors to prevent undesired flow of current from them to other objects.

joint housing

The part of a premolded mechanical splice that protects the crimp connection from the elements.

kcmil

1,000 circular mils.

mastic

A pasty material that is used as a protectant.

megohm

A unit of resistance that is equal to 1,000,000 ohms.

megohmmeter

An instrument that is used to measure the high resistance of electrical materials of the order of 20,000 megohms at 1000 V.

Mil

1/1,000 of an inch.

PDD

Power Distribution Department

polarization

The action or process of producing a counter electromotive force through the application of an electric field. The result is a relative displacement of positive and negative bound charges.

stress cone

A cone that is built inside a splice that gradually alleviates dielectric stress that is caused by a change in insulation thickness.

XLPE

Cross-Linked Polyethylene.


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Commissioning Cables and Terminations

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