Adaptability analysis of directional element in photovoltaic power station

Abstract

By the end of 2015, the total installed capacity of photovoltaic power generation in China was 43.18GW, surpassing Germany and becoming the country with the largest installed capacity of photovoltaic power generation in the world[1],[2]. As an essential supplement of large power grid, distributed power has developed rapidly with its advantages of high efficiency and environmental protection. Photovoltaic power stations are mushrooming all over China's light-rich areas. However, the access of photovoltaic power stations has profoundly changed the operation characteristics of AC power systems[3]. The original single power system has become a dual or multi-power system, which makes the directional elements in conventional relay protection have adaptability problems. In this paper, PSCAD/EMTDC is used to build a grid-connected model of photovoltaic power station. Through theoretical analysis and simulation verification, the adaptability problems existing in the application of directional elements in photovoltaic power station are introduced in detail. Theoretical analysis and simulation results show that zero sequence element is not affected by photovoltaic power station grid connection, positive sequence element, negative sequence element, phase fault component direction element, phase fault component direction element cannot be applied to photovoltaic power station.