Effect of Grounding Resistance and Lightning Arrester Non-linear Characteristics in Electrical Distribution System
Keywords:lightning arrester, Alternate Transient Program (ATP), high voltage, grounding resistance
Lightning Arresters (LAs) are widely used in electrical distribution system for the protection of various electrical equipment of distribution sub-station. For the protection of those sub-station equipment including sub-station transformer, the insulation coordination study is performed which determines the voltage level of electrical equipment in order to ensure their protection against over-voltages. The lightning impulse withstand voltage level or basic impulse insulation level (BIL) of substation equipment depends on grounding condition and nonlinear characteristics of lightning arrester apart from the magnitude of lightning surge. Hence, it is highly essential to analyze the effects of grounding condition and non-linear characteristics of lightning arrester in order to determine optimized value of BIL of equipment so as to prevent failure and over-investment. In this research work, the lightning over-voltage study is performed for an 11 kV overhead distribution line terminated by a transformer. For the fulfillment of the objective of research work, the sixty cases have been simulated and the lightning impulse withstand voltage levels or BIL of the transformer have been analyzed for all the cases through computer simulations on Alternative Transient Program (ATP). In this context, this research work proposes multiple lightning arresters for the protection of 11 kV sub-station transformers under different grounding conditions. With the introduction of more than one lightning arrester, is has been observed that lightning impulse withstand voltage level or BIL of equipment has reduced a lot.
Copyright (c) 2022 Mukesh Gautam, Arbind Kumar Mishra
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