Fault Detection in Photovoltaic (PV) Based Low-Voltage DC Micro-Grid

Abstract

Direct current (DC) power system is an upcoming technology promising technology in the existing world with certain advantages like high efficacy, flexibility and simple integrated to clean sources as compared to AC systems. This paper presents a low-voltage (LV)-DC micro-grid protection system. The LV-DC micro-grid consists of interconnects distributed resource like photovoltaic (PV) and sensitive electronic loads. Compared to AC micro-grid system the DC micro-grid is a new emerging field, so one main issue with DC micro grid is the protection. So, different control schemes of fault detection and protections are used of DC micro-grid for a well-functioning power system operation. In this work, the knowledge/idea of the existing power systems is used for designing the protection system in a PV based LV-DC microgrid. The understanding from existing AC power system can be used whiling designing a LV DC micro-grid protection system. This work includes the principle of operation and technical data of over current relay and differential relay in LV dc protection devices. Moreover, different faults and their detection schemes like over current fault detection and Differential fault detection are carried out through simulations. The study reveals that the completions which may arise due to high-impedance ground faults cannot be determined easily.