Investigation of Fault Analysis for Renewable Energy Microgrid

Abstract

The impact of all types of faults on system operation (islanded or grid-connected) was explored.• The increment of the value of THD by 92% to 93.5% from its normal value indicates a fault occurrence. • The value of the fault current specifies the type of protection system (fast or slow) in microgrid systems.This paper investigates the behavior of four bus grid-connected systems during different types of faults. The microgrid comprises a utility grid, a solar PV energy system, a diesel generator, and a load. Symmetrical and unsymmetrical faults at the microgrid distribution network were studied. These faults were applied at the solar PV bus under constant irradiance and temperature. The active and reactive power from the solar PV was synchronized based on the maximum power point tracking (MPPT) solar inverter. The total harmonic distortion (THD) for the load current response was also measured for each symmetrical and unsymmetrical fault. A protection system was strategically located based on specific constraints, such as fault location and detection. The simulation results were categorized into two scenarios: normal and abnormal conditions during faults in the distribution lines. The obtained results revealed significant differences in fault currents depending on the type of fault, which consequently influenced the selection of the appropriate protection system. The operation mode of the microgrid, whether in isolated or microgrid-connected mode, varied according to the fault type. Furthermore, the THD value of the load current exhibited a substantial increase during fault conditions. MATLAB/Simulink was utilized for conducting all the simulations.