The Research And Production Of Selective Leakage Protection Device In Low Voltage System

Mine selective leakage protection device is more and more widely used in coal mine power system, the reliability of leakage protection device is an important guarantee for safe operation in coal mine power system. Reliable detection of leakage fault signal is a common problem in leakage protection device, especially in the coal mine power system of low voltage, when the fault of single phase to ground occurs, the fault signal is weak, with all kinds of interference in the system, it is very difficult to get reliable signal detection, it is a major problem need to solve in the leakage protection device.According to the difficult problem of fault signal detection, the system focuses on how to get and process the zero sequence current signal and zero sequence voltage signal, on one hand, on the choice of sensor, applied precision zero sequence current transformer and zero-sequence voltage transformer; on the other hand, in the signal processing circuit, proposed the application of programmable gain amplifier for signal adaptive gain adjustment, and used integration filter element of program control, to improve the sensitivity and reliability of the signal acquisition. The system applied the single-chip of ATMEGA64as the controller, used zero sequence power method for leakage fault line selection, finished the system design of hardware and software, and set up the simulation power system in the laboratory, then set different system parameters and leakage fault parameters, did the experiment of leakage fault line selection, tested the performance of leakage protection device, completed the design and production of leakage protection device.