Series Dynamic Braking Resistor Based Protection Scheme for Inverter Based Distributed Generation System

Abstract

High penetration of inverter based distributed generation (IBDG) in power system increases fault current level. However, according to new grid code fault current level must be kept within specified limit during contingencies in order to ease detrimental effect on power grid. This paper proposes series dynamic braking resistor (SDBR) based protection scheme for IBDG. SDBR is connected with the AC side of the IDBG to insert resistance during contingencies. Fault detection scheme is developed based on point of common coupling (PCC) current. DC link voltage controller of IBDG is developed with feedback mechanism such that the net active power exchange with DC link capacitor is zero. Inner current control strategy is developed for IBDG to transfer DG power to the grid. Different faults are applied in the system to show the effectiveness of the proposed SDBR based protection scheme. The proposed SDBR based control scheme have been found as an effective solution to limit the fault current for IBDG system as evident from the simulation results.