Fault detection system of single-phase grounding based on electric field sensor

Abstract

In order to ensure the safety of power workers, the electric field strength value around the transmission line can be obtained in real time, and the ground fault line can be found at the first time. In this paper, a single-phase ground fault detection system based on electric field sensor is proposed. The low-pass conditioning circuit is used to collect the induced voltage generated by the sensing unit in the electric field, and then the electric field strength near the line is calculated in real time; Perform finite element simulation on single-phase grounding faults of transmission lines to observe changes in the electric field in space; Establish an ESP-NOW protocol communication system based on the ESP32 module, collect the measurement data of the electric field sensor and transmit it to the QT software interface for display;;Build a power frequency uniform electric field test platform, measure and correct the electric field strength of the PCB sensing unit, and verify the COMSOL electric field strength simulation value; Use the verified electric field strength simulation value to calibrate the electric field measurement and sensing unit of the parallel semicircle plate, establish a transmission line model in the laboratory, and measure the electric field strength before and after the single-phase ground fault occurs in the transmission line. Through the electric field intensity measurement curve, it is verified that the electric field sensor can obtain the change of electric field intensity and the fault line information in real time after the single-phase grounding fault occurs in the transmission line, so as to ensure personal safety.