Communicationless Overcurrent Relays Coordination for Active Distribution Network Considering Fault Repairing Periods

Abstract

This paper presents an integrated overcurrent relays coordination approach for an Egyptian electric power distribution system. The protection scheme suits all network topologies, including adding distribution generation units (DGs) and creating new paths during fault repair periods. The optimal types, sizes, and locations of DGs are obtained using HOMER software (Homer Pro 3.10.3) and a genetic algorithm (GA). The obtained values align with minimizing energy costs and environmental pollution. The proposed approach maintains dependability and security under all configurations using a single optimum setting for each relay. The calculations consider probable operating conditions, including DGs and fault repair periods. The enhanced coordination procedure partitions the ring into four parts and divides the process into four paths. The worst condition of two cascaded overcurrent relays from the DGs’ presence viewpoint is generalized for future work. Moreover, a novel concept addresses the issue of insensitivity during fault repair periods. The performance is validated through the simulation of an Egyptian primary distribution network.

Application of Under-Impedance Criterion to Protect against Effects of Phase-to-Phase Short Circuits in Medium-Voltage Networks

“…The introduction of under-impedance protection may also mean obtaining certain benefits related to eliminating the effects of voltage dips. This protection is particularly important in lines using synchronous motors, adjustable electric drives, or sensitive IT equipment voltage dips, and accompanying a short circuit, it may lead to many negative effects on the operation of such devices or the stability of their operation [26][27][28][29]. Microprocessor circuits are the most sensitive to voltage dips [26,30].…”

“…This protection is particularly important in lines using synchronous motors, adjustable electric drives, or sensitive IT equipment voltage dips, and accompanying a short circuit, it may lead to many negative effects on the operation of such devices or the stability of their operation [26][27][28][29]. Microprocessor circuits are the most sensitive to voltage dips [26,30]. These phenomena may result in interruption of control for technological processes, lack of signal transmission, or errors in their transmission.…”