Design Of Automatic Test Equipment For Signal-Phase To Ground Fault On The Power System

The unearthed or compensated neutral networks are mainly applied in our country's distribution systems. The single-phase to ground fault is principal fault in those systems. If this fault couldn't be found and disposed, the multiple-phase to ground fault will be happened and power supply will be interrupted. At present, the devices for single-phase to ground fault line selection all have deficiencice and can't be suit of the appeal of the present-day power system'development. It will be very significative of inventing of a new reliable and intelligent device .Through analysising the characteristics of the power system with floating neutral point deeply, the paper puts forward a new plan of single-phase to ground fault line selection on the base of S's signal injecton method and gives the hardware and software design .In this design, the high speed sampling and data processing is carried out through using DSP processor; the large electrice current is drived through the application of a high-performance audio power amplifier and transformer; the communication between host computer and detectors is realized through RS485 bus technology; the difference multilevel frequency-selected amplifier is designed and the feeble signal of space is sampled on the base of the theory of magnetic induction; the interface between DSP and exterior chip and RS485 interface logical is designed through using FPGA; the using of LCD module and keyboard interfacing chip makes the interface between human and machine; the programme of host computer and detectors is designed through using blocking design method.The result indicates that the systematic software and hardware is designed correctly, which satisfies the designing requirement.