Islanding Detection of Utility-Grid Interfaced PV Inverter with OVP/UVP and OFP/UFP Protection Relays

Islanding detection is a major concern for utility-grid interfaced photovoltaic power generation systems due to workers and equipment safety issues. To detect the passive islanding scenario, this paper presents the design and development of over/under voltage protection (OVP/UVP) and over/under frequency protection (OFP/UFP) schemes for utility-grid interfaced PV inverters. To track parameters at the Point of Common Coupling (PCC), such as voltage and frequency, and then turn off the inverter when the transition from normal defined conditions is successful. The Non-detection Zone (NDZ) is derived. The MATLAB/Simulink environment is used to develop for utility-grid interfaced PV system. Different active and reactive power mismatches are used to validate the proposed OVP/UVP and OFP/UFP protection schemes using extensive simulation studies.