Design Of Distribution Network Automated Monitoring And Fault Analysis System

Combining domestic and foreign network fault location technology and the characteristics of the domestic distribution network, the paper determines the zero sequence current phase comparison method as the judgment basis of the fault location.The ground forms a loop with line-to-ground capacitance when single-phase ground fault occurs on the line. At this time the system and line generate zero-sequence voltage and zero-sequence current. According to the formula derived and vector diagram analysis, we can know the phase difference between zero-sequence current and zero sequence voltage in non-fault line and fault line. In the fault line, the phase of zero-sequence current behind the zero-sequence voltage 90 degrees, but the phase of zero-sequence current front the zero-sequence voltage 90 degrees in non-fault line.This paper uses the STM32 microprocessor to compose a small online data collector.The UTC(Coordinated Universal Time) and 1PPS(1 Pulse Per Second) which is supplied by BD/GPS(Beidou and Global Positioning System) dual-mode timing module trigger device to collect data synchronously. The method of calculating phase is DFT(Discrete Fourier Transform) algorithm which has strong filtering capability and widely used in the field of power collection. Ad hoc network is constructed by the ZigBee wireless network,and it transmits the phase data which collected from each of the lines to data processing center by relay. ZigBee technology can implement data zero error transmission. Data processing center can control the operating parameters and status of the distribution network dynamically, and ultimately it can locate the fault line and position quickly.