Effect of power electronic protections of inverters on protection of micro-grids

摘要

Microgrid protection is one of the main challenges in the advancement of power system. The use of a static switch for microgrid protection is proposed by many researchers. But, in the present literature, the effects of power electronic protections of inverters on microgrid protection are overlooked. The inverter is protected from overcurrents by DESAT protection present in driver circuit. The static switches are at present based on silicon controlled rectifiers (SCRs) which operate much slower than inverter protection. This paper simulates a grid connected inverter with SCR based static switch and DESAT protection of IGBTs in MATLAB/Simulink environment. The effects of IGBT protection on the operation of a static switch are analyzed based on the simulation results. The analysis shows that not only the fault current is limited but the harmonics are also introduced due to inverter protection leading to maloperation of static switch. The static switch needs to be operated faster than DESAT protection of driver circuit.