Optimal protection coordination of voltage-current time based inverse relay for PV based distribution system

Distributed energy resources (DERs) are electricity source generator to meet small scale electricity requirement. DER is gaining much importance nowadays due to its high efficiency and zero emission. To meet the peak demand integrating more number of DERs at the distribution section directly without disturbing the transmission section thus avoiding the losses from generating station to distribution section. As the density of the network increases the overall operating time also increases. The fault current impact from the PV based DER is very small the relay will be in stationary mode. To improve the performance of these inactive relay near PV distribution system the author has proposed a new voltage-current time inverse relay characteristics, as the operating time is inversely proportional to the rise in current and fall in bus voltage. The protection coordination problem is solved by using differential evolution algorithm. The proposed method is tested for IEEE 14 bus distribution system. The obtained results are validated with standard time inverse relay to check the superiority of the proposed method.