EVALUATION IMPACT OF SOLAR PV SYSTEM ON THE OVERCURRENT PROTECTIVE RELAYS ON MEDIUM VOLTAGE DISTRIBUTED LINES
Rooftop solar power system (PV) connected to the distribution grid brings many benefits, such as adding a clean, on-site power supply to the load, reducing CO2 emissions, promoting sustainable energy development. However, when integrating a large amount of solar power into the distribution grid, they will affect the safe, and reliable operation of the power grid, including the operation of the relay protection system. This paper focuses on studying the influence of the solar power system on the sensitivity, selectivity, and coordination of overcurrent protection devices in medium voltage grids. A typical medium voltage line is used to calculate and verify the operation of overcurrent relay protection. Calculation results with different PV penetration scenarios and connection points show that integrating solar power sources can lead to nuisance tripping, mal-operation, loss of coordination of protective devices. The degree of impaction depends on the penetration rate and connection point location.