Design of Grounding System for High Voltage Substations
Dwarka Prasad1, H.C.Sharma2
1Dwarka Prasad, Research Scholar, Department of Electrical Engineering, Uttarakhand Technical University, Dehradun, (Uttarakhand), India.
2Dr. H.C. Sharma, Professor & Head, Department of Electrical &Electronics of Engineering &Technology, Greater Noida, Gautam Budh Nagar, (Uttar Pradesh), India.
Manuscript received on July 22, 2013. | Revised Manuscript received on August 17, 2013. | Manuscript published on August 30, 2013. | PP: 61-65 | Volume-2, Issue-6, August 2013. | Retrieval Number: F1962082613/2013©BEIESP
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Abstract: The design of grounding system for high voltage substation is a challenging task. In any substation, a well designed grounding system plays an extremely vital role. Grounding system must be safe as it is directly concerned with safety of persons working within the substation. The ground resistance, grid resistance, ground potential rise, step and touch voltage criteria for safety, maximum grid current, minimum conductor size, electrode size, maximum fault current level and soil resistivity are the basic design quantities of the grounding grid system. In this paper the design of grounding system for 220 KV high voltage substations and simulation for calculation of required parameters has been presented. A careful analysis was carried out in order to obtain the magnitude of total fault current that may occur in the substation. Soil resistivity is a major factor influencing substation grid design. Therefore, a resistivity investigation and analysis was carried out in order to obtain accurate design results. All necessary parameters were computed and assumptions were made using the relevant formulas. It has also been tried to reduce the grid resistance as well as ground potential rise by selecting the proper horizontal conductor size and addition of ground rods. A step by step procedure for the essential design considerations has been considered. Finally, simulations were carried out using software known as ETAP Software for verification of the design. The method proposed for substation grounding is in accordance with IEEE Std 80-2000.
Keywords: Etap Software, Grounding Grid, Substation Design, Step and Touch Voltage.