Research On New Equipment Of Fault Line Selection In Indirectly Earthed

The single-phase-to-earth fault line selection is a long-standing problem in the operation of indirectly earthed power system. The paper discusses the practical significance and the value of this subject .when single-phase ground fault occurs in small current earthed system respectively,analysis of the steady-state and transient characteristics of its features. And analysis the data of single-phase ground fault in 6kV power system.In the analysis of small current grounding fault line of single phase, based on the current transient and steady-state features, two different methods are used, namely,the maximum value method of the absolute value summation of the measurement admittance mutual difference and summation of mutual integral of transient current. Finally, to improve the alignment accuracy, we use an effective combination of the transient and steady state line selection method to select the wrong line. The steady-state method increases the margin of protection and improve the accuracy of alignment,the current transient method have the advantages of high anti-interference ability, high protection margin and the characteristics of simple computation.Selecting device 32-bit DSP chip to the central control unit TMS320F2812 new integrated protection system, The chip with high speed and superior performance,can effectively achieve monitoring the voltage and current parameters.The device can display real-time clock and the bus voltage, the line and the time will be displayed when the single-phase ground fault occurs,povided convenience for the operators.