Electrified Detection Methods Study On Zero Sequence Current Transformer Consistency And Polarity

In the distribution network, the zero sequence current transformer is an importantdevice to reflect the ground fault. Zero sequence current transformer polarity andconsistency will determine the grounding line selection device can operate correctly. thezero sequence current transformer polarity and consistency must be clear before theinstallation of selection unit and protective devices. At present, the zero sequencecurrent transformer polarity and consistency testing method is to make the systemoutage, then, we can check the polarity and consistency of the zero sequence currenttransformer. With the increasing demand for power supply reliability and repeated toreduce the power plan,power outage detection of zero sequence current transformerpolarity and consistency will not only result in power loss, and also be difficult. in theimportant area. So, the electrified detection of zero sequence current transformerpolarity and consistency is important.System during normal operation, the system time with high-voltage, can not bedirectly applied a incentives to system,we imposed high frequency signal from thesecondary side of protective current transformer. Take advantage of frequency ofexcitation signal that would make cable equivalent reactance and capacitance to achieveresonance. At this time, the equivalent reactance of the cable and the capacitance of thecapacitor cancel each other out, the impedance of high frequency signal is the smallestin the primary circuit, then, we can inject high frequency signals.For how determine polarity and consistency by high frequency signal. We deriveand analyze feature of high frequency signal in the primary circuit and find thecorrespondence between right and wrong of polarity and consistency. When the systemis running, As long as we can obtain information of the detection signal, we candetermine the zero-sequence current transformer polarity and consistency. And throughsimulation results show the feasibility and reliability.For online operation, high current would flood the high frequency signal. How toextract the detection signal from the background of the strong current, This topicexplore and research.the subject of the weak signal detection. This paper have studied aAdaptive Sinusoidal Algorithm, The algorithm can effectively filter out all kinds ofstrong background and extraction to the fixed frequency signal amplitude and phase,this paper carried out a detailed theoretical analysis of Adaptive Sinusoidal Filter. By simulation results demonstrate its accuracy and reliability.