Reliability assessment of PV location based on a new coordination and failure rates of protection relays to minimize indices energy

Abstract

Protection relays are crucial to analyzing how photovoltaic (PV) systems improve network dependability during disturbances. Thus, an in-depth analysis is performed to determine how PV integration affects the nominal load current of the medium voltage (MV) line. This analysis helps determine appropriate pickup currents in overcurrent (OC) relay protection systems. This requires careful relay operation times, exact estimations of the highest and lowest short-circuit values, and methods to mitigate the impact of interfacing inverters across PV penetration levels. In energy indices calculation, a final study proposes new restrictions coordination between OC relay and PV in-feed current protection. A method for computing the energy not supplied (ENS) metric takes into account the harmonized operation of principal and secondary OC relays and PV system current-based protective actions at their connection points. The simulations have shown that the proposed method is better at lowering the ENS's yearly value than the standard method, which includes PV. Consequently, the reliability indices will reach the minimum value and to showcase the efficacy and precision of the provided analysis, the ETAP software program is utilized as a demonstrative tool. Without failure rate modification, the EENS is 144643.500 MWh/year, and the ENS is 478.155 h/year. After PV integration, bus failure rates dropped 35% compared to the relay coordination situation. As a result, the EENS equals 158435.755 MWh/year, and the suggested method lowers the ENS's annual weight by 47.5% compared to the conventional way.

Keywords

• ENS
• Failure rates
• Coordination limits
• OC relay
• PV faults
• PSM