This worksheet helps you to calculate the following. Effect of increasing the grounding grid resistance of a. 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. The grounding grid system of a practical 220 kv substation is calculated by matlab program. Power substation design calculations a checklist of 18.
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. Design of grounding system for an electrical substation. A setup without adequate bus support and underrated bus support insulators will collapse. Grounding system for high resistivity limited area substations in hilly region of himachal pradesh. Design and analysis of substation grounding grid with and. 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. 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. Download limit exceeded you have exceeded your daily download allowance. 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. 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. Pdf a simplified method for calculating the substation.
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. This bulletin is an update and revision of previous rea bulletin 651, design guide for rural substations revised june 1978. 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. Earthing calculations for safe system design greymatters. A quantitative analysis of the effects of lightning surges is also beyond the scope of this guide. Optimal substation ground grid design based on genetic. Substation engineers must accurately assess the condition of grounding systems to ensure they are capable of dissipating additional fault current. Performance analysis of actual step and mesh voltage of. 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. Calculationofimportantdesignparametersforgroundingsystemsinsu.
Grounding design calculations part four electrical knowhow. This calculation is based on ieee std 80 2000, guide for safety in ac substation grounding. An electrical substation is a serioussource in a power system. Personal protective grounding for electric power facilities. That what must be provided is ground resistance r 5 ohms minimum. All rus borrowers rus electric staff effective date. The matrix method was used in this work since it is the simplest and the most basic theoretical tool for ground resistance calculations. Medium voltage products technical guide the mvlv transformer. Physics with electrons to the atlas detector scholarlycommons. Some substation designs require fence grounding to be isolated from the main ground grid.
A welldesigned grounding system will safeguard reliable performance of the substation over its entire service life. Ieee guide for safety in ac substation grounding ieee std. This software uses fem for calculating grounding indices 6. 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.
Welldesigned grounding system is very much essential as far as the safety of the crew and the substation equipments are concerned. Substations involves many earthlings through individual electrodes, which will have fairly high resistance. Grounding system for high resistivity limited area. Grounding systems are very important for the safe construction of a substation or a simple building. Aspects of soil resistivity measurements, area of the ground grid, calculation of tolerable limits of. Grounding design calculations part seventeen electrical. 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 design volume ii physical layout instructor. Tylavsky, chair john undrill raja ayyanar arizona state university. Design of grounding system for high voltage substations. 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.
Optimal design of grounding system for a substation is complex due to the involvement of numerous parameters. Design of earthing system for 400 kv ac substation a case study. X pdf of parton i carrying a fraction of momentum x at scale mx. Overly conservative values of soil resistivity and grid current will increase the cost dramatically. Substation grounding system resistance calculations using. 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. Other changes and additions were made in the areas of gasinsulated substations, the equations for the calculation of grid resistance, and the. Index terms conductor material saving, ground rods, optimization of substation grounding grid, sveraks method. 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. Two or more distinct but adjacent facility grounding electrode systems that are intentionally. Always comply with nec when equipment grounding conductor should be sized larger than the values listed in this calculator. Grounding electrode calculations using the matrix method. Earthing calculations regarding your safety youre overdue an update.
Steps to ensure effective substation grounding part 1 eep. Cost effective grounding grid design for substation. Pdf substation grounding system resistance calculations. A simplified method for calculating the substation grounding grid resistance article pdf available in ieee transactions on power delivery 92. Other changes and additions were made in the areas of gas insulated substations, the equations for the calculation of grid resistance, and the. Abstract the design of grounding system for high voltage substation is a challenging task. The maximum touch voltage within a mesh of a ground grid. Part of the earth fault current will thus be diverted to a remote earthing grid via the cable armouring. Optimal design of substation grounding grid based on. A simplified method for calculating the substation grounding. The first guide for the substation grounding design was introduced on 1961. Cost effective grounding grid design for substation soni m, dr.
The equation numbers used in this paper refer to the numbers used in. 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. No attempt is made to cover the grounding problems peculiar to dc substations. Review of substation grounding practices, safety and. Abstractthis paper proposes a method of grounding system analysis in the presence of satellite electrode for hilly region. Design of earthing grounding system in a substation grid. It is essential to determine the soil resistivity and maximum grid currents to design a substation grounding system. Ieee standard 80 substation grounding nema standards electric equipment construction national electrical safety code. Calculationofimportantdesignparametersforgroundingsystemsi. The touch and step voltages are directly proportional to these values. 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 grid. Flow of the earth system, cause voltage gradients ground level which case different parts of the earth and the reference ground round.
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. 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. Tying the fence ground into the main ground grid, as shown in fig. If ground resistance is r 5 ohms, i have to provide extra ground wires and extra ground rods. In any substation, a well designed grounding system plays an extremely vital role. Wellman, optimal ground grid design for large ehv substations with autotransformer, publication no.
Substation engineers need to know the condition of a. Ground fault current distribution when a ground fault. Ieee 802000 page 64 states the simplest approximate and estimated formula for grounding system resistance in uniform soil as. Ground fault current distribution when a ground fault occurs. Abstract substation grounding is a critical part of the overall electric power system. Etap model for earth mat design etap model for earth. Ieee guide for safety in ac substation grounding ieee std 802000. Design of earthing system for 400 kv ac substation.
Today, i will explain the other methods for performing of grounding system design calculations. 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. International journal of engineering trends and technology. This voltage, gpr, is equal to the maximum grid current times the grid resistance. This substation grounding course covers effective relaying and insulation of equipment. 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. I am trying to calculate this, but i do not have here any grounding software or any book with a calculation. 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. The study also analyses the effects of wind loading, snow loading, bus material, etc. Grounding system must be safe as it is directly concerned with safety of persons working within the substation. 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. Student 2,3assistant professor 1,2,3 department of electrical engineering 1, 2, 3 g. Substation grounding training the electricity forum. The supporting data has been obtained from actual field tested at the substation.
Nomographs method in article grounding design calculations part three. Earthing design calculations performing earthing design calculations, using one of the standards above, is an involved and time. Substation ground system insures safety of personnel, which deserves considerable attentions. Design procedures for grounding system design as per ieee 80. 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. 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. Design of earthing system for 400 kv ac substation a case. Calculations of allowable and actual step and touch potentials shall be done in accordance with ieee 80 using the following parameters.
Determining the soil resistivity to design a good substation. Pv ground referencing requirements and sample calculations ede sp by. Also, i explained the second method of grounding design calculations. Ac substations in article grounding design calculations part ten where i explained the following. Datadriven qed fits are not competitive anymore with the semianalytical calculation of the photon pdf using the luxqed formalism in terms. 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 means that the ground rods of both source and load side substations have to carry this current to or from the groundmass. This paper examines various methodologies for the calculation of different grounding systems. It is necessary to know some terms for designing the grounding grid in substation. 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. Safe process of a substation appeals for a welldesigned and properly installed grounding system. Spreadsheet to calculate the size of neutral earthing. As seen in the video, a piece of substation bus is subjected to extreme forces generated by fault current. The neutral point of transformer to the earth ground network provides a reference point of zero volts.
1426 1324 461 714 235 1531 758 1400 839 1101 512 1092 1155 516 189 416 1567 956 692 546 351 926 1525 501 671 739 1056 968 1608 1592 157 1365 415 1305 438 810 1003 1497 721 1478 311 1098 482 870 1193