Design and analysis of substation grounding grid with and. Grounding systems are very important for the safe construction of a substation or a simple building. Ac substations in article grounding design calculations part ten where i explained the following. Design of grounding system for high voltage substations. A welldesigned grounding system will safeguard reliable performance of the substation over its entire service life. The maximum electrical potential that a substation grounding grid may attain relative to a distant grounding point assumed to be at the potential of remote earth. Wellman, optimal ground grid design for large ehv substations with autotransformer, publication no. Substation design volume ii physical layout instructor. Earthing design calculations performing earthing design calculations, using one of the standards above, is an involved and time. That what must be provided is ground resistance r 5 ohms minimum. The study also analyses the effects of wind loading, snow loading, bus material, etc. Earthing grid conductor sizing touch and step potential calculations ieee std 80 is quite descriptive, detailed and easy to follow, so only an overview will be presented here and ieee std 80 is.
This document and other three revisions on 1976, 1986, and 2000 are the main helping tools for engineers in designing a substation grounding mat systems 68. If 1ohm is still in circulation on your documentation then this section applies to you even though the earthing calculations for determining a safe system earth ground has shifted away from an arbitrary resistance figure, usually substation earthing grid at both ends. Online calculator for calculating earthing system this online calculator will help you to quickly and accurately perform the calculation parameters of the grounding system in the twolayer soil, consisting of vertical earthing. Two or more distinct but adjacent facility grounding electrode systems that are intentionally. The cymgrd software is a substation grounding grid design and analysis program specially developed to help engineers optimize the design of new grids and reinforce existing grids, of any shape, by virtue of easy to use, builtin danger point evaluation facilities. The equation numbers used in this paper refer to the numbers used in. Earthing calculations regarding your safety youre overdue an update. Medium voltage products technical guide the mvlv transformer.
Power substation design calculations a checklist of 18. This worksheet helps you to calculate the following. I began explaining grounding design calculations for second type of buildings. Safety calculations and recommendations report of split factor derivation details of the ground potential rise gpr calculations written report with executive summary basic substation grounding analysis service code 770002 pointtopoint continuity measurements of the substation ground grid. Introduction in designing and construction of an electric substation, one of the most important issues that must be considered is designing of protective system to the earth. Review of substation grounding practices, safety and. Ground fault current distribution when a ground fault. Effect of increasing the grounding grid resistance of a. Can determine transfer potential impact on a neighbors fence, along with mitigation that identifies a nonmetallic fence location and length that would mitigate the transfer potential from the substation fence. Nomographs method in article grounding design calculations part three. Abstract substation grounding is a critical part of the overall electric power system.
This voltage, gpr, is equal to the maximum grid current times the grid resistance. Grounding system for high resistivity limited area substations in hilly region of himachal pradesh. Datadriven qed fits are not competitive anymore with the semianalytical calculation of the photon pdf using the luxqed formalism in terms. Substation engineers must accurately assess the condition of grounding systems to ensure they are capable of dissipating additional fault current. Earthing calculations for safe system design greymatters. A simplified method for calculating the substation grounding grid resistance article pdf available in ieee transactions on power delivery 92. The substation design manual is not intended to replace asset management standards, but rather to act as a reference document that crossreferences existing standards and process documentation and plugs any gaps where asset management documentation does not exist. Design of grounding system for an electrical substation. Calculations of allowable and actual step and touch potentials shall be done in accordance with ieee 80 using the following parameters.
Basic substation safety requirement quantities include ground grid resistance, mesh touch potential and step potential, moreover, optimal design of a substation ground system should include both. Overly conservative values of soil resistivity and grid current will increase the cost dramatically. It is necessary to know some terms for designing the grounding grid in substation. A simplified method for calculating the substation grounding grid. When the system neutral may not available, earthing transformer may be used to obtain the neutral. Steps to ensure effective substation grounding part 1 eep. Design of earthing grounding system in a substation grid. This bulletin is an update and revision of previous rea bulletin 651, design guide for rural substations revised june 1978. Substation grounding training the electricity forum.
A quantitative analysis of the effects of lightning surges is also beyond the scope of this guide. Also, i explained the second method of grounding design calculations. This substation grounding course covers effective relaying and insulation of equipment. Abstract the main purpose of this paper is to acquaint the reader with various types of grounding systems prevalent in an electrical substation and their importance. Substation ground system insures safety of personnel, which deserves considerable attentions. If ground resistance is r 5 ohms, i have to provide extra ground wires and extra ground rods.
Physics with electrons to the atlas detector scholarlycommons. This means that the ground rods of both source and load side substations have to carry this current to or from the groundmass. Brief discussions about different parameters which affect the designing of an. Grounding electrode calculations using the matrix method. International journal of engineering trends and technology. Welldesigned grounding system is very much essential as far as the safety of the crew and the substation equipments are concerned. Design of earthing system for 400 kv ac substation. Performance analysis of actual step and mesh voltage of. Flow of the earth system, cause voltage gradients ground level which case different parts of the earth and the reference ground round. Aspects of soil resistivity measurements, area of the ground grid, calculation of tolerable limits of.
Today, i will explain the other methods for performing of grounding system design calculations. Tying the fence ground into the main ground grid, as shown in fig. Pdf a simplified method for calculating the substation. The matrix method was used in this work since it is the simplest and the most basic theoretical tool for ground resistance calculations. Ieee 802000 page 64 states the simplest approximate and estimated formula for grounding system resistance in uniform soil as. Grounding design calculations part four electrical knowhow. Abstract the design of grounding system for high voltage substation is a challenging task. For protective grounding purposes, any electrical facility with a grounding electrode system ground mat which bonds all conductive, noncurrent carrying parts of equipment and for the control of surface potential gradients. Available grounding area, a 64 m x 84 m grid spacing, d 7 m ground rod length 10 m for 38 rods allowable touch voltage 838. In my novemberdecember 1997 article titled a substation is not just a fence, i discussed the fallacy of using a fence as a quick and inexpensive fix to electrical facilities with clearance problems. Determining the soil resistivity to design a good substation. Grounding system of a distribution hvmv substation consists of the substation grounding electrode and many outgoing mv cable lines acting as external grounding electrodes, andor conductive connections with the grounding systems of the supplied mvlv lowvoltage substations 20. Etap model for earth mat design etap model for earth. Design of earthing system for 400 kv ac substation a case.
Ground fault current distribution when a ground fault occurs. No attempt is made to cover the grounding problems peculiar to dc substations. The first guide for the substation grounding design was introduced on 1961. Other changes and additions were made in the areas of gasinsulated substations, the equations for the calculation of grid resistance, and the. Spreadsheet to calculate the size of neutral earthing. Personal protective grounding for electric power facilities. Cost effective grounding grid design for substation. Index terms conductor material saving, ground rods, optimization of substation grounding grid, sveraks method. In fact, if the ground grid in a station were not in place, anyone standing next to a breaker that operates stands a good chance of being shocked. Substation grounding system resistance calculations using. In any substation, a well designed grounding system plays an extremely vital role.
Substation engineers need to know the condition of a. X pdf of parton i carrying a fraction of momentum x at scale mx. Optimal substation ground grid design based on genetic algorithm and pattern search by qianzhi zhang a thesis presented in partial fulfillment of the requirements for the degree master of science approved november 2014 by the graduate supervisory committee. Cost effective grounding grid design for substation soni m, dr. This software uses fem for calculating grounding indices 6. The substation grounding grid is a system of horizontal, interconnected bare ground conductors, spaced a few meters apart, buried in the earth at a depth varying from 0.
Optimal design of grounding system for a substation is complex due to the involvement of numerous parameters. Grounding system for high resistivity limited area. Always comply with nec when equipment grounding conductor should be sized larger than the values listed in this calculator. Calculationofimportantdesignparametersforgroundingsystemsinsu. Substation grounding grid design therefore requires calculating of parameters related to earth and grounding with a great concern for the safety of the persons who may come under the influence of the potential gradient due to severe earth fault. Pdf substation grounding system resistance calculations. Design of earthing system for 400 kv ac substation a case study. Download limit exceeded you have exceeded your daily download allowance. Substation grounding plays the primary role in several key aspects of fault clearing, equipment preservation and, most importantly, personnel protection as well as protection of the passing public. Optimal design of substation grounding grid based on. Design procedures for grounding system design as per ieee 80. Substations involves many earthlings through individual electrodes, which will have fairly high resistance.
The grounding grid system of a practical 220 kv substation is calculated by matlab program. A setup without adequate bus support and underrated bus support insulators will collapse. All electrical equipment in the substation, substation yard, and within 5 meters of the substation fence shall be connected to the grid or to a ground bus connected to the grid. A simplified method for calculating the substation grounding.
The supporting data has been obtained from actual field tested at the substation. As seen in the video, a piece of substation bus is subjected to extreme forces generated by fault current. Abstractthis paper proposes a method of grounding system analysis in the presence of satellite electrode for hilly region. Some substation designs require fence grounding to be isolated from the main ground grid. Student 2,3assistant professor 1,2,3 department of electrical engineering 1, 2, 3 g. In mv and hv substations, where the source and load are connected through long overhead lines, it often happens that the ground fault current has no metallic path and has to flow through the groundmass earth. Ieee guide for safety in ac substation grounding ieee std. This calculation is based on ieee std 80 2000, guide for safety in ac substation grounding.
The neutral point of transformer to the earth ground network provides a reference point of zero volts. Ieee guide for safety in ac substation grounding ieee std 802000. Rg rho4 x sqrtpia10 where rg is the substation ground resistance in ohms rho is resistivity of the soil in ohmm a is the area occupied by the ground grid in square meters pi3. Substation design manual i reference ni000401r121 ver 2 ergon energy corporation limited abn 50 087 646 062 ergon energy queensland pty ltd abn 11 121 177 802 revision history version description of change approval date revised by 1 initial version 250320 draft 2a. Grounding system must be safe as it is directly concerned with safety of persons working within the substation. An electrical substation is a serioussource in a power system. Grounding design calculations part seventeen electrical. Optimal substation ground grid design based on genetic. The touch and step voltages are directly proportional to these values. Other changes and additions were made in the areas of gas insulated substations, the equations for the calculation of grid resistance, and the. Calculationofimportantdesignparametersforgroundingsystemsi. All rus borrowers rus electric staff effective date.
I am trying to calculate this, but i do not have here any grounding software or any book with a calculation. It is essential to determine the soil resistivity and maximum grid currents to design a substation grounding system. Safe process of a substation appeals for a welldesigned and properly installed grounding system. The maximum touch voltage within a mesh of a ground grid. Cymgrd, substation grounding program the cymgrd software is a substation grounding grid design and analysis program specially developed to help engineers optimize the design of new grids and reinforce existing grids, of any shape, by virtue of easy to use, builtin danger point evaluation facilities. This paper examines various methodologies for the calculation of different grounding systems. Part of the earth fault current will thus be diverted to a remote earthing grid via the cable armouring. Ieee standard 80 substation grounding nema standards electric equipment construction national electrical safety code. Pv ground referencing requirements and sample calculations ede sp by.
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