I am trying to calculate this, but i do not have here any grounding software or any book with a calculation. A connection to ground from the neutral point or points of a circuit, transformer, motor, generator, or system. Non neutral grounding methods are those used for grounding systems not solely involved to power generation or distribution. Effective design in substation grounding should have low ground resistance with tolerable step and touch voltage limit 23. The question of how a system shall be earthed is governed by the regulation. A system of conductors in which at least one conductor or point is intentionally grounded. Calculation of the preliminary grid resistance, rg, of the grounding system in uniform soil. Overhead transmission lines and underground cables 9. However, several arrangements can jointly exist in the same installation. Some empirical resistivity formula is used in this paper to present the apparent resistivity of. System grounding and earthing types analysis software etap. Solid grounding is universally adopted for following reasons. Pdf grounding systems are very important for the safe construction of a substation or a simple building.
Current flow through circuits seeking the path of least resistance. The practical technique of time sitting calculation for protection system is demon strated in section 4. The general purpose of earthing system is to protect life and property in the event of 5060 hz faults shortcircuit and transient phenomena lightning, switching operations. A er you have installed your grounding system, baseline recommends that you measure the ground resistance at all grounding points including the twowire and the enclosure ground. Specific resistance is calculated on the basis of measured values of soil resistivity. Principles of electrical grounding john pfeiffer, p. Comparison the performances of three earthing systems for. Ieee guide for safety in ac substation grounding ieee std. No part of this publication may be reproduced in any form. Today, the three system earthing arrangements, defined by standards iec 60364 and nf c 15. The cdegs software package current distribution, electromagnetic fields, grounding and soil structure analysis and its various subpackages have been designed to analyze problems involving electromagnetic fields, electromagnetic interference, and grounding with a global perspective, starting literally from the ground up. Given the capital importance of the soil resistivity data for adequate grounding system design calculations, a welldefined quality control program is required in the field to demonstrate that.
How to calculate the size of a grounding conductor. Grounding analysis for utility scale photovoltaic power plant. The differences arise from the specific requirements of the manufacturing or process operations. An overview about the indicators of grounding system is given in section 3. For effectivelygrounded systems this ratio is usually at least 60% 2. Ieee guide for safety in ac substation grounding ieee std 802000. Sep 12, 2014 overview on etap capabilities in ground grid system design and analysis using ieee 80 standard and finite element method fem. The study undertakes a step by step manual calculation approach to designing a grounding system suitable for alternating current substations. All system earthing arrangements sea provide equivalent protection of life and property. This paper grounding grids of different configuration and sizes examines various methodologies for the calculation of different all the above grounding systems. Recommended practices for designing and installing copper. Index terms conductor material saving, ground rods, optimization of substation grounding grid, sveraks method.
Ground resistance is the measurement of the conduc ng connec on between the grounding system and earth. This calculation is based primarily on the guidelines provided by ieee std 80 2000, guide for safety in ac substation grounding. Article 250 is organized into 10 different parts that deal with specific requirements with regards to bonding and grounding. As we already understood that it is a choice between weather to deal. But for high and medium voltage electricity substations, a common design is to lay a mesh of grid with vertical and horizontal conductors. Ground impedance, and earth surface potentials of a ground system to address issues related to large grounding systems or systems in congested areas. The grounding design shall indicate the placement of horizontal grid conductors and ground rods for the grounding system. This paper focused 230 66 kv, substation grounding system and calculation results of required parameters at location of kalay region. Metal frame of the building or structure where the following methods are used to make an earth connection. Earth continuity conductor or earth wire size of earth continuity conductor earthing lead or earthing joint size of the earthing lead earthing. Software tool for grounding system design request pdf.
This paper presents 230 66 kv, substation grounding system and calculation results of required parameters. Ieee industry applications society atlanta chapter january 19, 2010 meeting 2. Utility scale systems 5 mw or greater present several challenges for properly designing grounding system for personnel protection concerns. Grounding electrode system and grounding electrode conductor part iii znec 250. Pdf the main purpose of this work is the development of an optimization model for the design of the grounding grid in electrical substations. A different voltage potential at two or more points along the grounding system caused by improper grounding and bonding that results in objectionable current flow over the grounding system. Guide to grounding systems electrical engineering portal.
If grounding is inadequate, current doesnt flow as intended, which. The purpose of this paper is to bring a brief compilation of grounding system calculation using the methodology of ieee 802000 standard and simulated by means of. Grounding system theory and practice ced engineering. University format manual, and that this project is suitable for shelving in the.
Grounding by rods incase of nonuniform soil could be more efficient than any other grounding system or it helps in reducing the ground resistance of other. Grounding design calculations part seventeen electrical. The grounded systems employ some method of grounding namely solid grounding, resistance grounding, reactance grounding, peterson coil grounding or zigzag transformer grounding. However each has certain advantages and inconveniences in other terms that may be important for a given installation. Ground fault detection using zigzag grounding transformer in. The conductor on the supply side of the service or separately derived system overcurrent protection device that. Substation grounding is a critical part of the overall electric power system. Each system earthing arrangement can be applied to an entire lv electrical installation. When the electrical contact is such that the circuit path through the body is across the heart, you have the greatest potential for death. Auckland bogota caracas lisbon london madrid mexico city milan. Guidelines on earthinggroundingbonding in the oil and gas industry first edition september 2016 published by energy institute, london the energy institute is a professional membership body incorporated by royal charter 2003.
The values of these parameters have to be kept within certain established emits, keeping. For domestic, commercial and industrial premises, grounding electrodes are usually sufficient to meet the basic requirements of a welldesigned grounding system. Pdf design of charts for ground resistance calculations of. Grounding locations assessment of practical power system. The earthing system is designed so that the allowable touch and step voltages. As the skin becomes moist, the contact resistance drops. Guidelines on earthinggroundingbonding in the oil and gas. Pdf grounding system design in electrical substation. This bulletin is an update and revision of previous rea bulletin 651, design guide for rural substations revised june 1978. If ground resistance is r 5 ohms, i have to provide extra ground wires and extra ground rods. Difference between earthing, grounding and bonding. The earthing system provides a reference potential for electronic circuits and helps reduce electrical noise for electronic, instrumentation and communication systems. How to calculate the size of a grounding conductor sciencing. This ensures a distributed grounding and reduces the risk of a customer not having a safe grounding.
This is a discussion of the basic principles behind grounding systems and how grounding is related to safety and the effective operation of circuit protection devices such as fuses and circuit breakers. The procedures for performing the grounding system design calculations can differ slightly according to the type of the building as follows. Most utility systems which supply service for commercial and industrial systems are solidly grounded. Calculationofimportantdesignparametersforgroundingsystemsinsu. Practical guide to electrical grounding systems and applications. Groundingandbonding nationalelectricalcode article250 byjim. The groundings of buildings, substations and the utility grid as a whole could be considered as nonneutral grounding. Substation grounding grid design therefore requires calculating of. An important aspect of substation grounding system design is the calculation of the ground resistance offered by the grounding grid, and the values of the mesh and step voltages on the surface. Aspects of soil resistivity measurements, area of the ground grid, calculation of tolerable. Wayne beaty third edition mcgrawhill new york san francisco washington, d. I general ii system grounding iii grounding electrode system and grounding electrode conductor iv enclosure, raceway, and service cable grounding v bonding. Design and analysis of substation grounding grid with and. The best possible way to attain the system neutral for grounding purpose in threephase systems is to use source transformers or generators with wyeconnected windings.
Overview on etap capabilities in ground grid system design and analysis using ieee 80 standard and finite element method fem. The grounding system is essential to protect people working or walking in the vicinity of earthed facilities and equipments against the danger of electric shock. Some of the factors that are considered in a groundmat study are the following. Grounding design calculations part one electrical knowhow. Simplified method for substation grounding system design. General method of electrical earthing installation step by step. The resulting earthing types are displayed both on the one line diagram and for the various connected cables. Proper grounding is essential for the proper operation of electrical circuits.
This discussion, given by david lewis, pe, grounding and power systems at easypower, highlights some of these challenges and provide methodologies to accurately assess the grounding system performance with regard to ieee std 80. System earthing at ehv level in case of hv system above 33kv capacitive ground current is large enough to neutralize the earth fault currents hence no resistance is required in neutral to earth connection. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. As shown in figure 1, the human bodys resistance varies from as low as 500 ohms to as high as 600,000 ohms. For two layer model soil, the calculation of apparent resistivity is considered very important issue since the absent of a specified method to find it.
Numerical calculation of static current field of grounding system based upon the method of moments and the application of the onedimensional line elements is described here. That what must be provided is ground resistance r 5 ohms minimum. The grounding conductors at the transformer and at all customers are interconnected. Section 2 presents the steps of fault calculation for selected system configuration with moveable ground ing point. C transformer the system grounding on the system fed by the transformer is determined by the transformer secondary winding configuration.
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