A Comprehensive Review on Distributed Feeder Protection Problems in the Gaza Strip 22/0.4 kV Overhead Power Distribution System – A Case Study

Abstract

This paper provides a perspective on protective system at 22kV overhead feeders in Gaza distribution network using symmetrical components method and ETAP software. Electrical disturbances from high rate of outage feeders at the 22 kV overhead power lines frequently cause disruptions on the generating plant and customer loads. One sub-transmission feeder from a parallel set of ten 22 KV feeders (140 MW) in the Gaza west substation is selected as a case study in this research. Because the protection system lacks a data fault recorder (DFR), the paper calculates the fault currents at both the nearest substation bus and the last bus in the distributed feeder using the symmetrical components method and verifies the results by using ETAP software simulation. The results from calculating the minimum fault at the last bus indicated that the current protective parameters are reasonable and satisfied for detecting and interrupting the occurring faults. This author paper proposes increasing the fault clearing time at farthest feeder bus to make protective functions less sensitive by adjusting TMS to 0.08 for time overcurrent and earth fault and setting pickup level to 3.8 for instantaneously overcurrent. The design model is run on the selected feeder, and simulation results guarantee the proposed model's accurate performance for both overcurrent and earth faults after changing the fault clearing time. There will be no miscoordination of protective devices or operational risks while running the design model for the selected feeder with new settings. Gaza's distribution feeder network requires structural improvements to become more reliable and to reduce the high rate of feeder trip, and practical recommendations to improve current installation distribution grid are included in this paper.