The Study On Single-phase Adaptive Reclosure Of Transmission Lines With Series Capacitance

High-voltage transmission lines of single-phase fault consists of permanent fault and instantaneity,and instantaneous fault is the main form of single-phase fault line.In order to improve the system reliability and stability,automatic reclosing is widely used in the transmission line.Automatic reclosing is a fixed delay reclosing,so there is a situation that it will be reclosed in the permanent fault.In this case,it can make the power system be destroyed once again by the impact of the failure,may cause oscillation in power system,and makes the circuit breaker poor work in a bad conditions.So before registration to the nature of the fault judging to realize adaptive rcclosing is very meaningful.Transmission line with series compensation capacitance of the transmission line can shorten the electric distance,decrease network loss,improve system stability advantages such as more and more,so it gets people's attention.So,the research of identifying the circuit fault propertiesis very meaningful for the transmission lines with series compensation capacitance.In this paper,it will mainly analyze the different frequency voltage in the time of recovery voltage,and get the criterion of identifying the transient faults' and the permanent faults by the analysis.Firstly,this paper make a study of the line of shunt reactor and series compensation capacitor,and established 500kv transmission line model with series compensation capacitors.It pull a laplace transform the equivalent circuit model under different fault condition on transmission line,calculates the frequency components it contains.Analysis under the different nature of the fault belt series compensated transmission line recovery voltage phase voltage contains the different frequency components,discriminant method of single-phase earth fault properties.Finally according to different frequency component of recovery voltage phase voltage model is established,using the least squares fitting to the voltage model for different frequency of the voltage amplitude frequency decomposed,finally through the transient faults and permanent faults of different voltage amplitude of frequency characteristics,it is concluded that with series compensation capacitors criterion of nature of single-phase earth fault of transmission lines.