Study on the Influence of Distributed Photovoltaic on Distance Protection of Collecting Line

Recently, distributed photovoltaic has exploded in growth, the different power supply characteristics and the formation of multi-terminal power supply network have had a great impact on the original distribution network protection. So the distance protection of collecting line with distributed photovoltaic is studied. Firstly, we analyze whether the faulty phase can be reliably identified from the phase selection component. And then it studies the adaptability of the impedance component according to three-phase short circuit, two-phase short circuit and ground fault. Finally, the simulation verification is performed based on RTDS. The simulation results show that the positive and negative sequence equivalent impedances of the distributed photovoltaic side are no longer equal, which results in the failure of the commonly used phase current difference mutation in phase selection. And when various types of faults occur in the collecting line, a large negative reactance will appear in the measurement impedance of the distributed photovoltaic side, causing the impedance component to refuse to operate.