Indus Grounding & Lightning Protection System

Electrical Grounding & Lightning Protection System

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Introduction

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Ground Audit

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Design

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Installation

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Product Details IEGS-GE

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Lightning Protection

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Test Procedures

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Services Offered

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ELECTRICAL GROUNDING Few years ago it would have been rare for anyone to talk about the importance of low resistance grounding and bonding except where mainframe computer systems, telecommunications equipment equipment or military military installations were being being discussed. discussed. Today, we live in a world controlled by microprocessors so low resistance grounding is now critical and is a popular topic of conversation Low Impedance Electrical Grounding is essential for safety and protection of Sensitive Electronic Equipment and also for the effective Lightning Protection System (LPS). It is the basis for any facility's power po wer quality assurance program.

According to the IEEE Green Book [3] (Recommended Practice for Grounding, ANSI/IEEE Standard 142-1982), the grounding electrode resistance of large electrical substations (utilities) should be 1 Ohm or less. For commercial and industrial substations the recommended ground resistance is 5 Ohms or less. This low resistance is required due to the high potential to earth of the electrical system. Many equipment vendors and communication companies require ground systems of less than 3 Ohms resistance. For Lightning Protection system, BS 6651 stipulates that the resistance to earth of the LPS measured at any point should not exceed 10 ohms. To prevent damage and insure proper operation of modern sensitive communications and electrical equipment, dissipation of lightning energy and good return paths for ground fault currents has become a necessity. These modern, sensitive equipments include Computer Systems and other Electrical and Electronic equipments in Banks, Offices Call Centers, Magnetic Imaging equipment, Telecom Installations & Microwave Towers, CNC Machines and other Sophisticated Electronic equipment used in different Industries Offices and Electric Power Substations. Proper grounding has other benefits, such as Enhanced Personnel Safety, Reduction in System Noise and Protection from Unwanted Voltages, Currents and Power Surges and Protection from Lightning. Without a proper “Low-Impedance Ground”, standard protection devices such as breakers - or transient voltage surge and lightning protection systems - are rendered ineffective. Several Electronic Equipment Manufacturers, especially Communications Equipment Manufacturers such as Ericsson, Lucent, and Motorola & Nortel may void their equipment warranties at sites where the ground system performance does not meet their explicit earth grounding requirements, typically 5 ohms or less.







GROUND AUDIT: TESTING OF EXISTING FACILITIES When Grounding systems are installed they are required to meet certain resistance criteria, such as 10, 5, 3 or 1 ohm. Unfortunately most grounding systems are not properly maintained and tested after installation. Since they are buried they are also difficult to inspect. The Grounding system in many of the Industrial & Commercial facilities are decades old and most of them are corroded and have undetected electrical discontinuities. These Problems often continue for many years, contributing to electrical problems, equipment failures and decrease in personnel safety. We do the Complete Audit / Evaluation of Grounding System & LPS by using Fall of Potential Method Testing for the Resistance values of the Existing Grounding System and suggesting the rectifications if necessary.

DESIGN, INSTALLTION & TEST-PROCEDURES In order to understand Electrical Grounding Design, Installation and Test -Procedures, it is necessary to review why grounding is important. The list below gives some of the basic advantages of an effective ground system. 

Limits voltage in an Electrical Distribution system to “Definite Fixed Values”

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Limits Voltage to within “Insulation Ratings".

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Provides a “More Stable System” with a minimum of “Electrical Noise” and “Transient over Voltage”. Provides a path to ground in fault conditions for quick isolation of equipment with operation of “Ground Fault Protection”.

Provides grounding of all conductive enclosures that may be touched by personnel, thereby “Eliminating Shock Hazards”. Reduces “Static Electricity” that may be generated within facilities.

Provides “Protection from Large Electrical Disturbances” (Such as Lightning) by creating a low resistive path to earth. ear th.







Computers are very sensitive electronic devices, and commonly experience data corruption in non-grounded or poorly grounded environments, as well as outright physical damage. This can easily happen at voltages less than can be felt by the human hand. Computer chips operate at 5 volts and less. Computer chips can be damaged by 10 volts, and and data corruption corruption can happen in many other cases. cases. More and More machineries are coming with electronics and microprocessors. The microprocessor chips themselves have become smaller and more densely packed. This decreases heat dissipation, and makes them less robust. Operating voltages have and continue to decrease to allow for this miniaturization. A digital "1" may be in the vicinity of 3.5 - 5.0 volts or less, and a "0" in the range of 0 - 1.5 volts. So smaller over voltages from transient conditions may result in operating errors and this can happen with improper grounding. Many people complain that the power from the power company is bad. Few of us must have gotten a power surge from the power company because their computer quit working. However, the real problem is usually not a surge from the P ower Company, but instead just a bad grounding. People spend money on surge protectors and line conditioners but usually do not get any improvement. On the other hand, those who simply ground their power outlets properly usually see their problems go away entirely, without needing a surge protector or line conditioner. A surge protector and line conditioner give additional protection, but we cannot get a "ground" by adding a line conditioner, surge protector or other equipment. You get a ground only by grounding. With computers, by far the most common devices to fail and need replacement are the modem, printer and printer port, sound card, video card and LAN card (network not grounded). Intermittent data corruptions are caused because the data travels at 4.7 volts or less inside the computer, yet the power outside is 220 volts. Without proper grounding/earthing, the exposed metal on the back of the computer is typically 40-100 volts and fluctuating. Data corruption comes from leakage current. If a telecom company's grounding systems falter, then equipment fails, calls drop and people are inconvenienced. Companies will have a difficult time staying alive in an increasingly competitive industry if their service levels decrease. With equipment sensitivity also steadily increasing, installing a ground right the first time is even more critical. Only through proper electrical site protection can telecom companies ensure effective grounding and the best protection for their cellular sites and switches. This may take relearning the basics and grasping the engineering design and testing process, but designing a proper ground will result in maintenance-free years of high-quality performance and eliminate the need for fo r rework or enhancement







SOIL RESISTIVITY TEST The first step in designing a proper “Electrical Ground” starts with soil resistivity measurements. It is a crucial first step on which the remaining steps in the process are based. Although not difficult, measuring soil resistivity can be time-consuming and requires training, practice and the right equipment, including a four-pole ground resistance test meter, reels of conductor and four probes. Soil resistivity measurements must be taken in at least three different directions at four or five probe spacing, even on the smallest land areas. This involves driving probes into the earth several times in each direction. The more probes and data, the more accurately the designer can model the site to provide the most effective design. Variations of soil resistivity can range from 500 ohm-cm in clay to higher resistivity in limestone - 5000 to 1,000,000 ohm-cm or more. Even in adjacent lots they dictate the ground system performance within each site.

Electrical Grounding Design Process Our extensive experience in the Designing of Electrical Grounding enables us to define exactly what grounding installations will work best for your site. This eliminates “Trial & Error”, and reduces the overall cost of the grounding system by designing only what is needed to meet your specifications. Armed with reliable “Soil R esistivity” esistivity” data and a site map, our designer can complete the ground system design very accurately. A sophisticated computer program uses this information to model the soil and grounding system and recommend the quantity, type, length and shape of the ground rods, including rod spacing and placement. plac ement. At this point, the drawings and other details are gi ven to our installation department.

Installation of IEGS The system we offer is called INDUS-Electrical Grounding System (IEGS). The INDUS- Electrical Grounding System (IEGS) is backed by a team of Professional Electrical Engineers who are experienced in the design, testing and application of all types of grounding rods and systems.







ADVANTAGES OF INDUS-ELECT INDUS-ELECTRICAL RICAL GROUNDING SYSTEM 

Accurate Mapping of Soil Resistivity of Sites

Soil Resistivity Measurement is an essential part in designing the Low impedance grounding and we do these measurements by using top of the line equipment and through universally accepted accepted Wenner Wenner method method developed by Dr. Frank Wenner of the the US Bureau of Standards. 

Designing through Software

“Proper Designing of G rounding System” System” is done, through the Internationally acceptable grounding Software to get the accurate design for the required value of Ground Resistance, prior to the installation of Grounding Pits / Rods , thus eliminating the “hit and trial method” to achieve the requ ired ground resistance resistance values. v alues. 

Permanent Soil Treatment Solution So lution

IEGS Ground Rod comprises of a 1” to 2 “or larger hollow copper rod. These electrodes are filled with an electrolytic salt mixture and derive moisture from the soil and atmosphere and utilize the moisture to slowly dissolve the electrolytes in the rod creating a conductive rooting effect, providing an ever increasing increasing lower resistance ground in any type of soil. 

Ground Conductivity Enhancing Material M aterial

The High Resistivity Native Soil from the hole bored for the installation of IEGS ground rods is replaced with the Low Resistivity Soil, called GCEM (Ground Conductivity Enhancing Material) which provides a good Conducting path by creating a direct low resistance electrical connection between the electrode and the earth.

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Reducing the Risk of Equipment Damage

The high resistivity native soil around the grounding electrodes can cause a high concentration in the electric field around an electrode, which in turn, may cause arcing in the soil to occur and can lead to the Equipment Damage. The use of GCEM (Ground Conductivity Enhancing Material) in our IEGS reduces impedance by increasing the effective contact area of the electrode to the soil thus reducing the risk of Equipment Damage.









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Making Valid Measurements of Electrical Groundin Grounding g

The neutral to ground voltage depends on wire size and length of the ground and neutral, quality of connections, resistance of ground pits/rods etc. Excessive voltage drop in the phases, high harmonics and poor Grounding shows high neutral to ground voltages. The variability in the many factors which affect the neutral to ground voltage partially explains that the neutral to ground voltage is not the VALID method of gauging the quality of Electrical-Grounding. The most accurate method of measuring the Electrical Grounding is the measurement of its “Resistance” through “Fall of Potential Method”. We use top of the Line equipment DET 5/4 R for the measurement of Ground Resistance which gives the most accurate results for the v alues of Ground Resistance.







IEGS-GE IEGS Ground Electrodes provide a low-impedance ground in locations of high soil resistivity. Together with GCEM as backfill, the system dissipates lightning energy and other dangerous electrical fault currents, even in sandy or rocky soil conditions. Features 1 to 2 inch OD copper pipe contains natural electrolytic salts that permeate into the surrounding soil, lowering resistivity. Available up to 20 feet in continuous length and longer rods can be field assembled using 6.66 feet sections Applications The IEGS Ground Electrode system is ideal for locations of high soil resistivity as well as the locations where Low Impedance Grounding is required More Information Ground Electrodes IEGS are self contained electrolytic grounding electrodes that extract moisture out of the air and from the earth on a continuous basis. This moisture mixes with and dissolves the metallic salts in the electrode that produces a continuous release of electrolyte into the soil. This dramatically reduces the resistivity of the soil around the electrode, thereby increasing the conductivity of the grounding system. The ground resistance continues to diminish as the electrolyte spreads further into the soil and is especially effective where the soil c onditions are sandy, rocky, or have other undesirable factors. In these cases, the lack of moisture or the lack of natural metallic salts fails to produce a natural, conductive, electrolytic solution on a con tinuing basis. Our Grounding system provides these missing low resistance ingredients. The IEGS incorporates several







LIGHTNING PROTECTION Cloud-to-Ground Lightning discharges can be hazardous to structures, people and installations or equipment in, on or connected to the structure. Lightning can cause damage to all or part of a structure or to the contents of a structure, especially to electrical and electronic system. Consequential effects of lightning damage may extend to the surroundings of a structure. To reduce lightning damage and its consequential effects, lightning protection measures are required. The basic idea is to provide lightning current a separate preferential solid path to ground. Today, a lot of international and national rules exist to employ all well-tried measures to protect life, structures and equipment. Account must be taken of the most important international standards, such as IEC 61024-1 and 61312-1 (protection of building structures against lightning and protection of information systems against LEMP – including radio transmitters), BS 6651 and others. They all define the proper planning, installation and inspection of effective lightning protection systems (LPS).

LIGHTNING PROTECTION DESIGN CONSIDERA CONSIDERATIONS TIONS All International standards stated above clearly advises strict adherence to the provision of a conventional Lightning Protection System (LPS) - to the total exclusion of any other device or system for which claims of enhanced protection are made. The principle components of a conventional structural lightning protection system, in accordance with these standards are:

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Air Termination Network Down Conductors Earth Termination Network

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Bonding (to prevent side flashing)

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AIR TERMINATION NETWORK NETWORK







AIR TERMINATIONS FOR TALL CONDUCTING STRUCTURES The zone of protection does not seem to be applied because of the need to interconnect the down conductors of the tall block to the a ir termination of the lower block. In such cases it is ne cessary to connect the lower air termination up to the lower d own conductors to facilitate this inter connection, even though this extension is within the zone of protection of the tower.

Zones of protection p rotection

The 'Zone of Protection' offered by an air termination network is considered to be 45º for heights up to 20m. Above this height, the zone of protection is determined by the 'Rolling Sphere Method'. This involves rolling an imaginary sphere of 60m radius over a structure. The areas touched by the sphere are deemed to require protection. On tall structures, this can obviously include the sides of the building.







EARLY STREAMER EMISSION TYPE AIR TERMINAL TERMINALS S The purpose of this type of air terminal is to emit a rising electrical discharge to inflect the effect of the downward tracer. As it is transmitted towards the cloud, this rising discharge creates a field which is sufficient to modify the path of the downward tracer: the lightning current is thus dispersed into the earth. This process can occur naturally, but the action of the IONIFLASH from FRANCE PARATONNERRES offered by IEGS triggers it more rapidly and therefore ensures more effective protection. protec tion.

DOWN CONDUCTO C ONDUCTORS: RS: Down conductor siting and distancing is often dictated by architectural circumstances. There should be one c onventional down conductor for every 20m or part thereof of the building perimeter at roof or ground level (whichever is greater). g reater). These should be evenly e venly spaced and distances apart of more than 20m avoided if possible. If the building is above 20 m in height or of an abnormal abnormal risk this distance should be reduced to 10m. They should be routed as directly as possible from the air termination network to the earth termination network to avoid risks of side flashing. Re-entrant loops are also to be avoided. BS 6651 recommends that the length of conductor forming the loop should not exceed eight times the width of its open side. Conventional Down Conductors: Conventional down conductors are un-insulated conductors, typically copper strip, or cable. To reduce the voltage rise, and the risk of side flashing multiple down conductors are required. The use of multiple down conductors and associated grounding systems, can add substantially to the cost. The ascetics of multiple down conductors have historically been an issue with architects and building contractors. The conductor size shall be at least 28 strands of 14-gauge wire wire rope lay, with a net weight of 2 375 pounds per 1,000 1,000 feet (70mm ), minimum. IEGS Down Conductors: INDUS has developed its dedicated insulated down conductor for use with its IEGS Lightning Protection range. The cable is des igned to provide a safe, insulated path, to ground for the captured lightning discharge. Less numbers of down conductors are required which allows for a simple high efficiency grounding network to be constructed. IEGS Down Conductors can be routed away from sensitive electronic equipment & requires a









Inner area requires no conductors as it is wi thin the zone of protection determined by the rolling sphere

EARTH TERMINATION T ERMINATION NETWORK NETWORK Each down conductor must have a separate earth termination. Moreover provision should be made in each down conductor, for disconnection from the earth for testing purposes. This is achieved with a test clamp of IEGS. The peak current carried by the primary discharge during a lightning strike is almost 33 kA, but can reach over 100 kA in some cases. Subsequent discharges (secondary strikes) typically carry one third of that current. The rise time of the primary strike is about about 4 micro seconds seconds while secondary discharges peak faster (less than 0.7 micro seconds) due to the fact that air ionization keeps the conductive channel open. This is why it is important to keep the selfresistance of the grounding system low; a high resistance system looks like an open circuit to these impulsive currents and is thus ignored. To transfer a collected lightning strike safely into the ground, an ultra-low impedance grounding system is necessary.







Parallel Earth Rods & Use of INDUS Electrical Electrical Grounding System-IEGS Where ground conditions make deep driving of earth rods impossible, a matrix arrangement of rods coupled to one another by conductors can be used. If possible, the earth rods must be spaced at a distance at least equal to their driven depth. If earth rods cannot be driven in a parallel line a INDUS –Electrical Grounding System (IEGS) configuration can be used, ensuring that the spacing/depth ratio is still maintained. High resistivity soil conditions can be overcome by backfilling earth rods with a suitable medium such as INDUS Ground Conductivity Enhancing Material (GCEM) conductive concrete which effectively increases the diameter of the earth rod and hence its surface area, thus lowering resistance to earth.

Spacing of parallel earth rod electrode







BONDING (To Prevent Side Flashing) It is important to keep the terminal contact resistance of a grounding wire to be lower than 0.1 ohms, to prevent melting during a lightning discharge, and the mass of copper in the terminal contacts should be large to keep their temperature down. A 150g copper terminal with 0.1 ohms contact resistance may melt during lightning discharge and provide no protection at all. IEGS grounding copper terminals provide the right solution to this problem. Bonding to prevent side flashing 1 Air termination 2 Down conductor 3 Bond to aerial 4 Bond to vent 5 Bond to re-bar 6 Bond to metal staircase 7 Bond to metal window frame 8 Bond to vent pipe 9 Bond to steel door/frame 10 Test clamp 11 Indicating plate 12 Main earthing terminal terminal of electrical installation 13 Earth termination point







SERVICES OFFERED

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GROUND AUDIT Testing of Resistance values of the Existing Grounding System & LPS and suggesting the rectifications if nec essary. SURVEY & SOIL RESISTIVITY TESTS Initial Survey of the New Sites for the Electrical Ground Installation and carrying out the Soil Res istivity Tests. DESIGNING OF LPS & ELECTRICAL GROUNDING SYSTEM using sophisticated computer program to model the soil and grounding system and recommending the quantity, type, length and shape of the ground rods, including rod spacing and placement along with the LPS system components. SUPPLY & INSTALLATION OF IEGS (INDUS-Electrical Grounding System) for Human Safety, Equipment Protection and LPS. TESTING AND VERIFICATION of the predicted Electrical Ground System Performance and finally the issuance of Certificate.

SOIL RESISTIVITY TEST







LOW IMPEDANCE GROUNDING, SOMETIMES REQUIRE DEEP BORING

Indus Grounding & Lightning Protection System

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