Large-scale Photovoltaic Transmission Line Protection Method Based on Voltage Drop and Current Polarity

Ensuring the safety and stability of photovoltaic grid connection greatly relies on safeguarding large-scale photovoltaic transmission lines. Therefore, A method for safeguarding large-scale photovoltaic transmission lines by utilizing voltage drop and current polarity as a basis. When a fault occurs, it is monitored in real time that the voltage drops and continues to drop, and the current polarity judgment is entered. The initial voltage drop point is used as the starting point of the fault, and the current polarity is determined by collecting the sign of the current sampling value 1/4 cycle before the starting point. sex. Then, faults inside and outside the area are determined by comparing the current polarity at both ends to achieve fault location. This paper verifies the proposed method under different fault locations, different transition resistances, different fault initial phase angles and weak photovoltaic output.