Research on Neutral Grounding Resistance Selection and Zero Sequence Protection for Grid Connected Photovoltaic Power Station

A centralized grid-connected photovoltaic (PV) station is a widely adopted method of neutral grounding using resistance, the reasonable selection of the neutral point grounding resistance is of great significance for both primary system security and secondary protection. Under the premise of ensuring the safety of personal and equipment, based on the variation characteristic curve of zero-sequence current with neutral grounding resistance, and comprehensively analyzing the selectivity and sensitivity requirements of zero-sequence protection of all levels of lines in the station, this paper proposed a method for selecting the neutral grounding resistance that takes into account the PV source boosting effect and protection action performance. The correctness and feasibility of the proposed method are verified by practical engineering examples.