PV 모듈 DC 어레이 지락 불검출 영역 및 고장위치 검출 방법

A DC ground fault detector measures the current flowing in the ground fault direction and compares it with a set value to determine whether a ground fault exists. A general DC ground fault detection method, with a non-detection dead band area, cannot detect when an accident occurs. Consequently, a DC ground fault cannot be recognized and greater damage may occur as an additional accident. In this study, the characteristics of DC ground faults were analyzed, and simulations were conducted based on the problems with the general DC ground fault detection methods. A proposed method to detect the detection deadband area that the inverter cannot detect was developed through the simulations. The simulation accuracy was measured by comparing the ratio of the fault point location in the detection deadband area to the steady state. Furthermore, a method for detecting the detection deadband area was proposed and verified by determining the presence or absence of a DC ground fault in the open state by installing an open switch in the normal state and the ratio of the fault point location.