GIS 12 801 26 November 2003

Document No.

GIS 12-801

Applicability

Group

Date

26 November 2003

Guidance on Industry Standard for Power Generators (IEC)

GIS 12-801

BP GROUP

ENGINEERING TECHNICAL PRACTICES

26 November 2003

GIS 12-801 Guidance on Industry Standard for Power Generators (IEC)

Foreword This is the first issue of Engineering Technical Practice (ETP) GIS 12-205. This Guidance on Industry Standard (GIS) is based on the following heritage documents from merged BP companies:

AMOCO (ACES) A EL-MT-546-P

Electrical—Generators—Synchronous—Supply Specification

ARCO (APCES) ES 406-91

Form-Wound Brushless Synchronous Generators 500 Horsepower and Larger

BP (RPSE) RP 12-11 GS 112-4

Electrical Systems and Installations - Generators Guidance for Specification High Voltage Induction Generators

BP Chemical US CP 17-3-3

Synchronous Generators

Copyright  2003, BP Group. All rights reserved. The information contained in this document is subject to the terms and conditions of the agreement or contract under which the document was supplied to the recipient’s organization. None of the information contained in this document shall be disclosed outside the recipient’s own organization without the prior written permission of Manager, Standards, BP Group, unless the terms of such agreement or contract expressly allow.

Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Table of Contents Page Foreword ........................................................................................................................................ 2 1.

Scope .................................................................................................................................... 5

2.

Normative references............................................................................................................. 5

3.

General.................................................................................................................................. 6 3.1. Documentation............................................................................................................ 6 3.2. Exceptions .................................................................................................................. 6 3.3. Conflicts...................................................................................................................... 6 3.4. Quality assurance ....................................................................................................... 6

4.

Standard design requirements ............................................................................................... 6 4.1. General....................................................................................................................... 6 4.2. Certification for use in hazardous areas ...................................................................... 6

5.

Special design requirements.................................................................................................. 7 5.1. Duty and rating ........................................................................................................... 7 5.2. Construction................................................................................................................ 7 5.3. Environmental protection ............................................................................................ 7 5.4. Windings and cable terminations ................................................................................ 8 5.5. Excitation system ...................................................................................................... 10 5.6. Bearings and lubrication............................................................................................ 11 5.7. Critical speeds .......................................................................................................... 12 5.8. Vibration ................................................................................................................... 12 5.9. Plant identification..................................................................................................... 13 5.10. Mechanical handling ................................................................................................. 13 5.11. Painting..................................................................................................................... 13

6.

Noise ................................................................................................................................... 14 6.1. Noise emission ......................................................................................................... 14 6.2. Noise reduction......................................................................................................... 14

7.

Tests.................................................................................................................................... 14 7.1. Standard tests........................................................................................................... 14 7.2. Overspeed test ......................................................................................................... 15 7.3. Heat run.................................................................................................................... 15 7.4. Vibration ................................................................................................................... 15

8.

Documentation..................................................................................................................... 15 8.1. Data sheet ................................................................................................................ 15 8.2. Coil quality and interturn tests................................................................................... 15 8.3. Winding data............................................................................................................. 15 8.4. Test documentation .................................................................................................. 15 8.5. General arrangement drawing................................................................................... 15

9.

Packaged units .................................................................................................................... 16 Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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9.1. 9.2. 9.3.


Package Requirements............................................................................................. 16 Special design requirements ..................................................................................... 17 Package testing ........................................................................................................ 19

Bibliography .................................................................................................................................. 20


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1.


Scope This GIS provides guidance on industry standard for the design, materials, fabrication, inspection, testing, documentation, and preparation for shipment of power generators based on IEC standards.

2.

Normative references The following normative documents contain requirements that, through reference in this text, constitute requirements of this technical practice. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this technical practice are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.

BP Engineering Technical Practices (ETP) GIS 12-051 GP 12-30

Guidance on Industry Standard for Transformers & Reactors (IEC) Guidance on Practice for Lighting and Small Power

British Standard (BS) BS 4999-140 BS 5000-3

General requirements for rotating electric machines—Part 140: Specification for voltage regulation and parallel operation of a.c. synchronous generators Rotating electrical machines of particular types of for particular applications—Part 3: Generators to be driven by reciprocating internal combustion engines

International Electrotechnical Commission (IEC) IEC 60034-1 IEC 60034-5 IEC 60034-6 IEC 60034-7

IEC 60034-14 IEC 60079

Rotating electrical machines – Part 1: Rating and performance. Rotating electrical machines – Part 5: Degrees of protection provided by the integral design enclosures of rotating electrical machines (IP code) – Classification. Rotating electrical machines – Part 6: Methods of cooling (IC code). Rotating electrical machines – Part 7: Classification of types of construction, mounting arrangements and terminal box position (IM Code). Rotating electrical machines – Part 14: Mechanical vibration of certain machines with shaft heaths 56 mm and higher – Measurement, evaluation and limits of vibration. Electrical apparatus for explosive gas atmospheres – All Parts.

International Standards Organization (ISO) ISO 281 ISO 492 ISO 1940-1

Rolling bearings – Dynamic load ratings and rating life. Rolling bearings—Radial bearings—Tolerances. Mechanical vibration—Balance quality requirements of rigid rotors— Part 1: Determination of permissible residual unbalance.


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3. 3.1.


General Documentation A specification suitable for enquiry or purchasing can be derived from this section of the GIS by retaining the technical body unaltered but omitting the data page and all commentary. This section of the GIS shall be read in conjunction with an enquiry or purchase order and all data sheets associated therewith. The purchaser and vendor shall both complete the data sheets.

3.2.

Exceptions Tenders for the supply of equipment against this section of the GIS shall either include an unqualified affirmation regarding compliance with this section of the GIS or a complete list of exceptions. A vendor may offer other suitable proposals if price or technical advantage may accrue, but such proposals shall form a supplement to the main tender.

3.3.

Conflicts If any of the reference documents conflict and the provisions of section 3 of this section of the GIS do not establish definition, then the vendor shall highlight this, and shall state the basis of design used.

3.4.

Quality assurance Verification of the vendor's quality system is normally part of the pre-qualification procedure, and is therefore not specified in the core text of this section of the GIS. If this is not the case, clauses should be inserted to require the vendor to operate and be prepared to demonstrate the quality system to the purchaser. The quality system should ensure that the technical and QA requirements specified in the enquiry and purchase documents are applied to all materials, equipment and services provided by sub-contractors and to any free issue materials.

4. 4.1.

Standard design requirements General Generators shall comply with all relevant parts of IEC 60034. Any requirement to meet other national interpretations of IEC 60034, with or without CENELEC Harmonisation Document requirements, must be identified and agreed in writing between the purchaser and the vendor. This procedure is intended to be the means by which particular local needs can be met whilst at the same time properly documenting deviations from the normal BP requirements.

4.2.

Certification for use in hazardous areas Generators for use in hazardous areas shall comply with the relevant parts of IEC 60079 or alternatively the relevant parts of the CENELEC 500XX series of documents or national variants. Generators for use in hazardous areas in the European Economic Area must comply with the relevant EN 500XX series CENELEC standards or national variants and these should be referenced in place of the IEC 60079 series for the relevant protection concepts. The manufacturer shall submit copies of the relevant certification documents with the tender. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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5. 5.1.


Special design requirements Duty and rating Generators shall have a continuous running duty designated as type S1 in accordance with paragraph 4.2.1 of IEC 60034-1. In addition, diesel driven units shall be capable of running at 110% load for one hour in every twelve. Diesel engines are permitted to develop for limited periods an output in excess of their rated output, this is normally 10%. As an electrical machine having a maximum continuous rating in accordance with IEC 60034-1 has no specified sustained overload capacity it is necessary to make this provision. There are no temperature rise limits specified for this overload condition. Generators shall be capable of meeting their specified duty for 26,000 hours (3 years) without being stopped for maintenance purposes. Alternating current generators driven by reciprocating internal combustion engines shall comply with BS 5000 Part 3 or equivalent.

5.2.

Construction Generator frame and enclosure shall be of welded steel plate and sheet to form a rigid, selfsupporting and torsion-resistant assembly that can be shipped in one piece. The base structure shall have adequate facilities for lifting, levelling, aligning and anchoring the entire machine. The preferred configuration of the generator and brushless exciter shall be horizontal construction with two or three pedestal-type sleeve bearings on a common baseplate, allowing separate removal of generator and exciter. The cooling arrangement shall be IC511 for air-cooled machines and IC71W for water-cooled machines. Cooling water for water-cooled generators shall normally have a maximum temperature of 25οC unless higher temperatures are specified in the data sheet. Cooler materials shall ultimately be matched to the cooling water analysis (furnished to the successful bidder) and the proposed materials shall be identified. Provision should be made within the generator to prevent leakage of cooling water on to the windings or rotating parts of the generator. In the case of critical (unspared) machines, consideration should be given to specifying heat exchangers with double tube arrangement. This will minimise the possibility of damage to the high-voltage stator winding, particularly in those situations where top-mounted coolers are employed. Horizontally mounted machines shall be IM 1001 and vertical flange mounted machines shall be IM 3011 in accordance with Code II of IEC 60034-7.

5.3.

Environmental protection The degree of ingress protection shall be in accordance with IEC 60529 and suitable for the application and installation site. If no data is available to indicate a more stringent specification and if an outdoor installation is involved, the protection shall be IP55. The degree of ingress protection required (IP55) is entirely suitable for situations where machines are not subject to excessive dust settlement or immersion in water. If any doubt exists then the particular conditions pertaining should be evaluated and a special enclosure agreed between purchaser and vendor. If the machine will be installed inside an enclosure a rating of IP20 may be contemplated. However if the enclosure is large and there could be moisture or dust/debris above the machine the minimum protection to be specified should be IP23 Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Machines shall be suitable for a Relative Humidity of 90% with occasional condensation. Anti-condensation heaters shall not be provided unless specified on the data sheet. If heaters are provided, they shall be easily accessible without requiring dismantling of the generator. The purpose of an anti-condensation heater is to preclude the possibility that the specified insulation level of the machine is seriously reduced by the entry of water or water vapour into the machine. Modern non-hygroscopic insulation materials largely obviate the possibility of this occurring and manufacturers generally take good care to ensure that all conducting items are insulated to a high standard. In order to prevent the ingress of water or other harmful matter prior to cabling, open cable entries shall be adequately sealed (IP55) before the generator is despatched from the manufacturer' s works. If a drain hole is provided, it shall be at the lowest point on the stator, subject to accessibility for the removal of the threaded plug when the machine is mounted in the service position. In the case of generators for use in hazardous areas, the drain hole shall be sealed with a draining device approved by the Certifying Authority. Care must be exercised to ensure that the means of removing and replacing drain plugs are not impeded by the position in which the generator is mounted. 5.4.

Windings and cable terminations Stator and rotor windings of the generator and exciter shall generally be constructed using class F insulation materials. During normal service, the temperature rise values of class B materials shall not be exceeded. The temperature rises shall be limited to class B unless the manufacturer offers class H insulation of proven design in which case the temperature rise to class F shall be considered. The required rating of a generator for a particular piece of driven equipment is usually defined by the supplier of the driven equipment, after taking into account any BP requirements. This rating takes account of any design uncertainty and manufacturing tolerances that may arise and therefore the generator should be suitable for all eventualities that may arise. Traditionally, industry has also 'built-in' a further safety margin for the generator by specifying class B temperature rises (80 °C) whilst employing class F insulation materials (105°C rise), both pertaining to operation in a 40°C ambient air temperature or with 25°C cooling water. If operating conditions are such that the machine is unlikely to be overloaded and if the ambient conditions are well removed from standard then consideration should be given to specifying class F rises for class F materials, especially when large machines are involved and significant weight or cost savings can be obtained. A similar argument may be used with regard to class H materials. The insulation system provided must generally be suitable for unrestricted service under the environmental and service conditions listed in this specification for a minimum service life of 20 years. Mechanical and thermal stresses on the windings encountered during normal and fault conditions shall not lead to fracture, deformation or loosening of the windings. For this reason, vacuum-pressure impregnated (VPI) insulation systems using solvent-free (temperature cured) epoxy resins and submersion of the entire stator assembly is preferred. Field repairs to these insulation systems must be possible. At least 2 winding temperature detectors shall be provided per phase.


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RTDs should be embedded in the slot portion of the stator windings between coil sides. Additionally thermocouples can be fitted in the endwinding portion of the stator winding. Windings shall be supported to ensure sufficient rigidity during normal conditions including direct on line starting. Insulated windings shall be non-hygroscopic and resistant to contamination and flame propagation. Stator windings shall be connected in star unless shown otherwise on the data sheet. Star points shall be formed internally but shall be disconnectable and accessible for measurements. The insulation level of machines that are required to operate on unearthed or on resistor earthed neutral systems with one line at earth potential for prolonged periods shall be highlighted by the manufacturer for specific approval be the purchaser. Details shall be provided of the Quality Assurance Specification that stator coils shall be manufactured and tested in accordance with section 8.2. Such a specification should be the method by which the insulation system is qualified. It should contain details of type tests and routine tests, and should demonstrate coil dielectric loss analysis and surge withstand capability. IEC 60034-15 contains details on impulse voltage withstand levels. A suitable Quality Assurance Specification is Electricity Association ‘Technical Specification 44-5, Testing the insulation system of stator coils for rotating electrical machines’. Terminations shall preferably be of the separable insulated connector type in an enclosure with ingress protection IP21 minimum for mechanical protection, and an adequate method of supporting the cables. Alternatively, terminal boxes shall be of the pattern specified on the data sheet. The main terminal boxes of the generator shall be sealed towards the generator interior and shall have ample room to terminate the feeder cables. Terminal boxes shall have rupture-diaphragms or equivalent means for the safe relief of ionised gases towards the generator enclosure in case of a terminal short-circuit. Conductors shall not be random but shall be layered or sectionalised (form wound) to ensure that the maximum design interturn voltage cannot be exceeded. The insulation system and the rotating diodes of the exciter/field circuit and the associated protective components shall be dimensioned such that a failure due to overload or loss of blocking/insulation capability is remote. The loss of a diode shall be detected by the monitoring system. Generator terminations shall preferably be of the separable insulated connector type in an enclosure with ingress protection IP21 minimum for mechanical protection, and an adequate method of supporting the cables. Alternatively, terminal boxes shall be of the pattern specified on the data sheet. The main terminal boxes of the generator shall be sealed towards the generator interior and shall have ample room to terminate the feeder cables. Terminal boxes shall have rupture-diaphragms or equivalent means for the safe relief of ionised gases towards the generator enclosure in case of a terminal short-circuit. The exciter shall have its own terminal box with provision for terminating the low-voltage supply cables. Generators, including the terminal box, windings and cable terminations, shall be entirely suitable for operation at the fault level specified in the data sheet when started and protected by the means also specified in the data sheet. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Means shall be available for electrically isolating individual stator windings from each other and from the main incoming cables without involving extensive dismantling of the machine or risking damage to either the windings or the cables. Space shall be provided for the installation, at the manufacturers works, of current transformers to be supplied by the purchaser. Heater or other auxiliary connections shall be clearly identified and brought out to a dedicated terminal box separate from the main terminal box. Exposed auxiliary wiring on the generator shall be run in galvanised conduit, or with cables in such a way that they cannot be damaged accidentally. When a threaded entry is required for an auxiliary cable, as identified on the data sheet, a detachable plate or box incorporating a threaded entry shall be supplied. The minimum thickness of the material used for this purpose shall be 8 mm. Threaded entries shall be tapped ISO metric with a constant pitch of 1.5 mm and to ‘medium fit’ tolerance class 6H. The size of thread required shall be as specified on the data sheet. 5.5.

Excitation system

5.5.1.

General

The excitation system shall normally be of the brushless type. A proven detection system to monitor the failure of any element in the rotating diode bridge shall be included. All components of the excitation circuit shall be sized to continuously satisfy the maximum flux demand of the synchronous generator. The insulation system and the rotating diodes of the exciter/field circuit and the associated protective components shall be dimensioned such that a failure due to overload or loss of blocking/insulation capability is remote. The loss of a diode shall be detected by the monitoring system. The excitation system should be complete without the need for external power supplies. Power may of course be derived from the generator terminals. The exciter shall have its own terminal box with provision for terminating the low-voltage supply cables. The excitation system shall be capable of providing at least 3 times rated current under three phase terminal short circuit conditions for at least 10 seconds. If a static thyristor exciter is required, a current limiting circuit shall be provided to prevent sustained overload. This circuit shall incorporate a timing unit to restrict the application of ceiling excitation for a specified time, after which the excitation is automatically reduced to the rated value. A separate protective device shall also be provided to give ultimate rotor overcurrent protection. Although it is necessary to initially provide a high excitation current during fault conditions to supply additional reactive power demanded during fault clearance, and to maintain a synchronous torque at low voltage levels, rotor current limitation is necessary to prevent the undesirable disconnection of the generator due to overload of the rotor circuit. 5.5.2.

Automatic voltage regulator (AVR)

The AVR shall be of solid-state design and include protection against over voltage. The AVR shall be provided with means to adjust the set point of the main generator output voltage over a range of plus or minus 10% of nominal voltage rating at full load. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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The generator shall be provided with a manual control for the excitation system as standby to the AVR, and the system shall trip to manual excitation upon failure of the AVR. The manual control set point shall automatically follow the AVR in order that a stepless changeover will occur should the AVR fail. It is often the case that failure of the AVR will be signified by an overvoltage demand which would make the AVR operate out of tolerance. If under this condition the manual follower would also track the AVR into the unacceptable operating region this would represent an undesirable situation and should be prevented. If a standby AVR is specified then automatic changeover should occur on failure of the main AVR and setpoint tracking of the main AVR shall occur in the manner described above for manual control. The AVR system shall have an adjustable reactive current droop characteristic and be suitable for reactive load sharing. Also known as Quadrature Current Compensation (QCC) this adjustment provides the ability for generators in parallel to share reactive current in equal or proportional amounts. When indicated on the data sheets, facilities will also be provided for the separate automatic control of reactive current. A separate control system may be utilised for reactive current control, this may be required for acceptable power system operation when for instance incoming generators are brought on to the system during take up of the load. The AVR system shall allow 100% voltage to be generated at 80% speed under all conditions of operation. Overfluxing control on both automatic and manual mode shall be provided. This shall not reduce excitation until frequency is less than 75% of rated frequency. Maximum excitation limitation and maximum volts/hertz excitation limitation facilities shall be included within the AVR units. The regulation capability of the main a.c. generation and AVR system under steady state and transient conditions shall be chosen from Voltage Regulation Grades 2.13 (VR2.13), 2.23 (VR2.23), 2.33 (VR2.33) or 3.11 (VR3.11) as defined in BS 4999 Part 140. Transient performance is defined with rated kVA at 0.8 power factor rejected, for other conditions agreement is required between supplier and purchaser. The lowest voltage regulation grade tolerable should be selected as choice of a grade better than is necessary will result in a larger, more expensive generator with a higher fault level. The temperature stability of the voltage regulation shall be better than 0.5% for temperature between the maximum and minimum ambient. 5.6.

Bearings and lubrication

5.6.1.

General

Sleeve bearings fitted to machines rated 2000 kW and above shall be equipped with resistance temperature detectors. 5.6.2.

Rolling element bearings

Rolling element bearings are preferred if an acceptable bearing life can be achieved. The life of rolling element bearings calculated in accordance with ISO 281 shall be in excess of 40000 hours when considering the forces generated by the generator alone, and in excess of 32000 hours when considering the additional forces generated by the prime mover Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Rolling element bearings shall be in metric sizes and comply with ISO 492 recommended dimensions. It shall be possible to relubricate rolling element bearings safely without stopping or dismantling the generator. The relubrication interval shall be specified by the vendor. Relubrication intervals should not incur an unreasonable maintenance burden. A minimum of 4000 hours for horizontal or 3000 hours for vertical generators is reasonable. Grease lubricated bearing regreasing facilities shall be arranged such that a maximum amount of old grease is displaced and ejected to the outside of the generator enclosure. The bearing shall be packed with grease before the generator is despatched. 5.6.3.

Sleeve bearings

Generators with sleeve bearings shall be provided with means to measure the air gap between stator and rotor at both ends, or any alternative means to ensure concentricity between stator and rotor. Generators with sleeve bearings shall be constructed to ensure an adequate supply of oil to all parts of the bearing surface under all conditions including rundown. This may be achieved with oil rings, discs or similar devices. Means shall be provided to prevent the escape of oil and oil level indicators shall be fitted. When a pressure fed or oil mist lubrication system is proposed by either the purchaser or vendor, full details shall be made available for consideration and acceptability. Generators without thrust or location bearings shall be defined as such and shown on the vendors documentation. The amount of permissible end float shall be stated to allow selection of a suitable coupling. The correct running position and limits of permissible movement of the rotor shall be permanently marked on the generator, and these markings shall be visible at all times. The generator rating plate shall be marked ‘Limited End Float’. All bearings shall be fully insulated to prevent the flow of shaft current unless type tests demonstrate that the shaft voltage measured at any operating conditions across the ends of the shaft is less than 150 mV rms. An earth connection, removable for test purposes shall be provided at the drive end bearing and no other connection shall bridge the insulation. 5.7.

Critical speeds The manufacturer shall state the design value of the first critical speed on the data sheet. The critical speeds of the rotor shall not be within 20% of the normal operating speed, twice normal operating speed, and any other significant exciting frequencies. Due to manufacturing tolerances there can be significant differences between the predicted and actual values of critical speed. The 20% tolerance on the design figure is used to provide an adequate safety margin. Critical speeds that lie below the operating speed shall be determined by run up and coast down of the machine during works test. For all flexible rotor machines a rotor dynamic analysis shall be undertaken by the manufacturer and the results submitted to the purchaser. The analysis shall include evaluation of the damped critical speeds allowing for bearing oil film together with housing, end shield and bedplate stiffness effects.

5.8.

Vibration Two-pole generators rated 1500 kW and above shall be fitted with dual non-contacting vibration probes at each bearing in accordance with API 670. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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In a manner similar to temperature monitoring either a complete ' package' vibration monitoring system may be required or a generator system alone may be required and will be separately specified. In either event generators shall be capable of accepting the necessary probes, either at the time of supply or later. Salient-pole generators rated 3000 kW and above shall be fitted with vibration monitoring devices at each bearing. Non-contacting vibration probes, in accordance with API 670, or accelerometers (rms velocity reading), in accordance with API 670, are acceptable. The limits of bearing housing vibration for generators not fitted with non contact vibration monitoring equipment shall meet the requirements of IEC 60034-14, table 1, vibration grade R. The vibration amplitude of generators fitted with non contact vibration monitoring equipment shall meet the requirements of IEC 60034-14, table 2, vibration grade R. It is important to note that the prime mover equipment vendor will also have specific vibration requirements that must be met by the generator. In some circumstances these requirements will be more stringent than IEC levels and can have a significant influence on generator design. If vibration probes are fitted to the generator and if the complete vibration monitoring system can be made available at the manufacturers works during works test then these shall be employed for vibration testing. It is not necessary that the generator manufacturer purchase the vibration monitoring system, it is acceptable that it be borrowed from others (e.g. the 'package' vendor). The vibration levels for machines fitted with flexible rotors when passing through the first critical speed shall be within the following limits:

5.9.

a.

Generators fitted with sleeve bearings shall have peak-to-peak amplitude less than 75% of the nominal bearing clearance.

b.

Generators fitted with rolling element bearings shall operate at less than three times the limits given in IEC 60034-14, table 1, vibration grade R.

Plant identification In addition to the generator rating plate, a separate generator plant equipment identification plate shall be attached to a non-removable part of the frame in a readily visible position. The plate shall be fabricated from stainless steel and the means by which it is attached to the frame shall allow for the plate to be removed and replaced by a similar plate. The identification plate shall be engraved with the plant tag number and the Works Identification Number (WIN) if made known to the manufacturer before despatch.

5.10.

Mechanical handling Facilities shall be provided for the application of jacking screws in all three planes, and their location shall be identified on the generator general arrangement drawing. If spreader bars are required used for lifting all or part of the machine or other special handling precautions are necessary, these requirements shall be identified on a suitable plate attached to the external surface of the generator.

5.11.

Painting Details of the manufacturers standard paint (or other type of finish) specification shall be submitted to the purchaser at the time of tender.


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6. 6.1.


Noise Noise emission The manufacturer shall provide details of the noise emission from his equipment in octave bands. He shall also provide details of any narrow band noise emitted by his equipment that is noticeable to the ear, together with the octave band or bands in which it occurs.

6.2.

Noise reduction If the noise-limiting requirements of this document cannot be met without the provision of noise-reducing features, the levels with and without these features shall be stated in any proposal.

7. 7.1.

Tests Standard tests The following tests shall be undertaken irrespective of generator rating: (a) ' Complete'tests in accordance with the list in table 1 for the first generator of each new design. The manufacturer may substitute validated test certificates in-lieu of carrying out the tests marked with an asterisk (*). (b) ' Abbreviated'tests in accordance with the list in table 2 on all generators not subject to ' complete'tests. (c) For generators with flexible rotors any critical speed which lies below the operating speed range of the generator shall be determined by means of a run up and coast down test. The tests included in the following tables are required to be carried out on all high voltage generators, although it is appreciated that, on occasion, manufacturers may have good reason for not being able to meet all requirements. In such a case the purchaser must be assured that adequate testing will be arranged so that the capability of a generator to meet the specified duty will be properly demonstrated. Table 1 - Complete Tests 1 2 3 4

Dielectric tests on completion of manufacture Measurement of winding resistance (cold) Measurement of no-load characteristic Direction of rotation with phase sequence

5 6

Measurement of short-circuit characteristic Measurements of losses to allow calculation of efficiency at 1, 0.75 & 0.5 pu load Determination of temperature rise at full load (using the zero power factor method) Momentary overload Measurement of noise Dielectric tests after heat run Measurement of reactances and time-constants Measurement of vibration during all running tests Final dielectric tests High voltage and continuity tests on built-in temperature detectors to demonstrate satisfactory operation and compliance with stated characteristics Determination of winding Polarisation Index Rotor overspeed test

*

7

* * * *

8 9 10 11 12 13 14

15 16


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The manufacturer may substitute validated test certificates in-lieu of carrying out the tests marked with an asterisk (*).

Table 2 – Abbreviated Tests 1 2 3 4

5 6 7

7.2.

Dielectric tests on completion of manufacture Measurement of winding resistance (cold) Measurement of no-load characteristic Direction of rotation with phase sequence Measurement of vibration during all running tests Final dielectric tests High voltage and insulation tests on built-in temperature detectors Determination of winding Polarisation Index Rotor overspeed test

Overspeed test A generator overspeed test, in accordance with the requirements of IEC 60034-1, shall be undertaken for all synchronous generators. The rotor shall be check balanced after the overspeed test. If the residual out of balance has increased by more than 10% then the rotor shall be rebalanced and the overspeed test and the check balance repeated until the rotor is stable and meets the requirements of ISO 1940-1

7.3.

Heat run Heat run (temperature rise) tests shall be conducted with the machine operating at rated voltage, load and speed.

7.4.

Vibration Vibration measurement tests shall be conducted with the machine operating at rated voltage and speed and mounted in a manner that is reasonably representative of site mounting conditions.

8. 8.1.

Documentation Data sheet The data sheet items indicated by a grey background need not be completed at the time of enquiry/tender. All items on the data sheet shall be completed at the time of order.

8.2.

Coil quality and interturn tests The manufacturer shall forward copies of test certificates, covering coil quality assurance procedures and coil interturn tests, to the purchaser at appropriate stages of tender and manufacture.

8.3.

Winding data Subsequent to the order, and prior to despatch from the manufacturer' s works, the manufacturer shall forward full winding details to the purchaser.

8.4.

Test documentation This shall be provided to demonstrate compliance with clause 8.1.

8.5.

General arrangement drawing The manufacturer shall include with his tender a general arrangement drawing of the machine, on which the following information shall be included as a minimum: Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Overall dimensions Mounting dimensions Shaft dimensions Lifting arrangement Jacking points Weight (net and gross) Minimum clearance dimensions for maintenance Bearing type Cable entry position.

9. 9.1.

Packaged units Package Requirements The vendor shall co-ordinate the design, and ensure the satisfactory functioning of the complete package. The satisfactory functioning of the complete package shall form part of the vendors guarantee. The scope of supply shall include the following : -

a.c. generator complete with associated excitation and voltage regulation equipment.

-

generator synchronising equipment

-

generator neutral earthing equipment

-

generator unit transformer (if required)

-

auxiliaries system motor control centre

-

auxiliaries low voltage motors

-

station battery and associated charging system

-

generator control panel

-

generator winding and cooling air temperature measurement and monitoring equipment

-

generator bearing temperature and vibration, measurement and monitoring equipment

-

auxiliary, main and emergency lighting, and small power distribution equipment

-

alarm and trip annunciators The above list is not exhaustive and should be amended as necessary. If a unit transformer is included in the scope, it shall operate successfully with extremes of voltage and frequency which the AVR will permit i.e. 100% voltage at 80% frequency. If the generator circuit breaker is included in the scope, electrical protection requirements should be identified in the Purchase Order.

The vendor shall declare at the tender stage a descriptive list of the materials comprising the package. If the prime mover or generator is mounted in an acoustic enclosure which gives rise to a hazardous area, equipment installed inside the enclosure shall be suitably rated and certified in accordance with IEC 60079, taking into account the extremes of temperature experienced during normal and emergency ventilation conditions. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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9.2.

Special design requirements

9.2.1.

Generator neutral earthing equipment

Neutral earthing equipment shall be supplied as specified in the data sheets. If an earthing transformer is specified it shall comply with GIS 12-051. An earthing transformer and resistor will be specified when the generator is to supply power through a unit transformer. Earthing resistors shall be provided with insulation suitable for the phase to phase voltage of the systems to which they are connected. They shall be designed to carry their rated fault current for 10 seconds, without any destructive effect to their component parts. The resistor shall be connected to the earthing grid directly. The design and materials of the resistor shall ensure that vibration and temperature variations cannot cause rupture, and that corrosion is minimised. The neutral earthing equipment may also include neutral switchgear if it is necessary to limit third harmonic current circulation between non-identical parallel- connected generators. 9.2.2.

Transformers

Transformers shall comply with GIS 12-051. 9.2.3.

Generator control instrumentation and alarms

The control panel shall include the following: •

a.c. generator synchronising and alarms

•

a.c. generator voltage regulation

•

a.c. generator protection

•

speed raise/lower

•

voltage raise/lower

•

emergency stop pushbutton

•

normal start/stop pushbuttons

•

excitation manual/off/AVR selector

•

trip/close switch and position indicator for generator circuit breaker

•

local/remote control selector

The package shall be complete for correct protection and operation with all necessary control equipment, logic systems and alarm annunciations. Controls shall be logically positioned and give ease of access when observing indicators and alarms during operation. If manual synchronising facilities are included in the scope then check synchronising relays shall also be included in the scheme. If automatic synchronising facilities are included then manual synchronising back up together with check synchronising relays shall also be provided. The drivers of all machines shall be fitted with speed governing equipment. If the generator is to operate in isolation the governor shall provide isochronous control. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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If the generator is to operate in parallel with other generators then adjustable droop control shall be provided. The following indication and alarms shall be included: •

generator voltage

•

generator current

•

kW meter

•

kVAr meter

•

power factor meter

•

frequency meter

•

kWH meter

•

hours run counter

•

exciter field voltmeter

•

exciter field ammeter

•

AVR/manual excitation null balance meter

•

running and incoming voltmeters

•

running and incoming frequency meters

•

synchroscope

•

synchronising lamps

•

alarm indication

Indicating instruments and alarm annunciations shall be easily visible and clearly audible and shall be located within the normal field of vision of an operator facing the control panel. The alarm annunciation shall include all alarms generated within the package. Facilities shall be provided to repeat single alarms or group alarms to a remote point. Selection of repeated alarms shall be indicated in the purchase order. As part of the bid the vendor shall identify all recommended indications and alarms that he considers necessary to monitor the performance of the package and to provide adequate protection of the equipment. Abnormal conditions which would ultimately lead to a shut down shall have warning pre-alarms. The interval between set points should be sufficient for corrective action to be taken. In the event of an equipment trip a ' first out'facility shall be provided to identify the original fault. 9.2.4.

Lighting and small power

The preferred type of luminaire is fluorescent. The emergency luminaires shall be supplied either from a central battery system or the integral battery type shall be used. A lighting uninterruptible power supply may be available when this type of installation proves to be the most economic, or when an extended standby time is required. If a UPS supply is available it should be utilised but one should not be provided specifically for the package. At least two normal lighting circuits shall be installed and both circuits shall be utilised in all areas. The design shall allow maintenance and modification of one circuit whilst the second circuit is in operation. Downloaded Date: 6/17/2008 10:16:17 PM The latest update of this document is located in the BP ETP and Projects Library

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Enclosures which personnel may enter for operation or on-line maintenance shall have emergency lighting. Small power outlets shall be provided as indicated by drawings and data sheets. Distribution within the package shall be by the vendor. 9.2.5.

Earthing

Connections to the bearing housings of generators having insulated bearing pedestals shall ensure that no connection, including that of the bearing sheath, provides a bypass around the insulation. 9.2.6.

Black start and stopping requirements

Unless specified otherwise there will be ' black start'power available for a main power generator driver from a ' black start'emergency generator. The vendor shall supply full details of all equipment requiring ' black start'power to enable the purchaser to provide the correct feeders. The vendor shall supply d.c. auxiliary power for the extended cooling down period when a gas turbine/generator unit is stopped to prevent thermal/mechanical damage. However, if the power requirements to achieve this would involve excessive battery requirements then a.c. power may be obtained from an emergency generator. 9.3.

Package testing Test programme shall include a combined test of prime mover and generator. The following tests shall be carried out: •

Load test against resistive and reactive load banks for eight hours duration at full load current and design power factor.

•

Rejection of full load current at the design power factor. Voltage, frequency and load current should be recorded on chart recorders.

•

A programme of further load acceptance and rejection tests should be devised and agreed including acceptance criteria during the bid analysis.

•

Generator control tests to demonstrate all generator trips and alarms and changeovers from duty to standby equipment.

•

Trip of main auxiliaries from generator fully loaded condition to demonstrate ability of emergency run down equipment.

Temperatures should be monitored in the vicinity of electrical equipment, especially if certified, to ensure design and certification limits are not exceeded.


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Bibliography [1]

ESI Standard 44-5, Testing insulation systems of stator coils.

[2]

EN 50209 Test of insulation of bars and coils of high-voltage machines.

[3]

IEC 60034-8

[4]

IEC 60034-15 Rotating electrical machines – Part 15: Impulse voltage withstand levels of rotating AC machines with form-wound stator coils.

[5]

IEC 60034-18

Rotating electrical machines – Part 18: Functional evaluation of insulation systems.

[6]

IEC 60060-2

High-voltage test techniques – Part 2: Measuring systems.

[7]

IEC 60072-1 Dimensions and output series for rotating electrical machines – Part 1: Frame numbers 56 to 400 and flange numbers 55 to 1 080.

[8]

IEC 60072-2 Dimensions and output series for rotation electrical machines – Part 2: Frame numbers 355 to 1 000 and flange numbers 1 180 to 2 360.

[9]

IEC 60079-1 enclosures “d”.

Electrical apparatus for explosive gas atmospheres – Part 1: Flameproof

[10]

IEC 60079-2 enclosures “P”.

Electrical apparatus for explosive gas atmospheres – Part 2: Pressurized

[11]

IEC 60079-7

Electrical apparatus for explosive gas atmospheres – Part 7: Increased safety “e”.

[12]

IEC 60079-10 Electrical apparatus for explosive gas atmospheres – Part 10: Classification of hazardous areas.

[13]

IEC 60079-15 “n”.

[14]

IEC 60212 Standard conditions for use prior to and during the testing of solid electrical insulation materials.

[15]

IEC 60317 Specifications for particular types of winding wires.

[16]

IEC 60529 Degrees of protection provided by enclosures (IP code).

[17]

IEC 60721-2-1 Classification of environmental conditions – Part 2-1: Environmental conditions appearing in nature – Temperature and humidity.

[18]

IEC 60751 Industrial platinum resistance thermometer sensors.

[19]

IEC 60851 Winding Wires – Test Methods.

[20]

IEC 60894 Guide for a test procedure for the measurement of loss tangent of coils and bars for machine windings.

[21]

IEC 61000-4-5 Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test.

Rotating electrical machines – Part 8: Terminal markings and direction of rotation.

Electrical apparatus for explosive gas atmospheres – Part 15: Type of protection


Page 20 of 21

26 November 2003


[22]

ISO 15

Rolling bearings – Radial bearings – boundary dimensions, general plan.

[23]

ISO 1132 Rolling bearings – Tolerances.

[24]

ISO 1680-2 Acoustics – Test code for the measurement of airborne noise emitted by rotating electrical machinery – Part 2: Survey method.

[25]

NEMA MG1

Motors and Generators.


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GIS 12 801 26 November 2003

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