Corelation Algorithm Research Based-on Fault Recorder

Fault recorder is a device that can automatically record power electrical harmonic and a variety of electrical data when fault and oscillating happen in power system. It is mainly used to detect actions of protection and automatic security equipments, find out variety rules of electrical variebles, and check power system calculation programmes and model parameters.A new algorithm is presented for real—time measuring the frequency in power system and used in the new manufacture of fault recorder.It can resist for non-periodic,low frequency and high-order harmonic signals with band pass filter. The The FDT could make the measure error becaμse of frequency excursion.The iterative algorithm and phase angle offset can greatly improve the precision of the frequency that deviates from power-frequency.The method is simple with fast calculation It can calculate accurately only in 2-2.5periods.This algorithm meet the national standard to pass simulation and national testing.The algorithm of line fault phase selector is designed and developed for fact demand.This improved algorithm is different from the traditional algorithm that only judge from one test candition .It judges with the ration of not only positive and negative but also positive and zero in weighted logicl.The improved algorithm can resist the transition resistance interference effectively.The margin phase is larger when the fault phase is certain.The judgment becomes perfact .It been verified on 800 spot and testing dataes and meet the demand.The new method of parameter measurement of power lines on operation is introduced in this pape based-on the characteristic of fault recorder. This method under operation can measure accurately the positive sequence parameter in the synchronized data of fault recorder.It measure the zero sequence of power lines becaμse of the zero current occurred in external fault. The method that is operated conveniently and need not cut power is different from the traditional mearsurement of zero sequence parameter that mμst cut power. The paper describes the algorithm theoretically and designs operating mechanism; questions actually.Those problems has been solved on simulation,and the range of error has been settled.