The Proposed Adaptive Reclosing Device Based On High Frequency Detection

In receny years,the proportion of the use of cable lines in the distribution network has increased year by year,and most of the faults that occur on the cables are permanent faults,which makes the traditional automatic reclosing has certain limitations.The traditional automatic reclosing has blindness.The short-circuit current generated when it coincides with a permanent fault will cause two impacts on the system and affect the power supply reliability of the power system.At the same time,the circuit breaker must break short-current continuous twice,this condition will reduce the service life and insulation capacity of the circuit breaker.In response to this problem,this article did the following:An adaptive reclosing device for distribution network based on an external high-frequency detection is proposed.This device injects a high-frequency detection signal into the fault feeder after a period of are extinction after the fault occurs.Windowed FFT analysis is performed on the transient voltage and current on the sampled fault feeder,and the type of fault is identified by the difference between the fundamental resistance of detection signal with the transient fault and the permanent fault.The parameters of the rectifier circuit components,filter capacitor capacity,and inverter circuit,component parameters,LC filter and pulse transformer in the adaptive reclosing device are designed.Using the PSCAD simulation platform to build a simulation model.the distribution line model including line type,distribution transformer,and equivalent load is designed.The simulation analyzes the effects of different fault locations,distribution line types,load capacity,inverter input phase angle,and transition resistance on the the fundamental resistance of detection signal.According to these influencing factors,the most unfavorable conditions are the transient fault of minimum value and the permanent fault of maximum value,so as to calculate the threshold of fault criterion and construct the fault criterion.The adaptive reclosure scheme proposed in this paper is compared with the scheme proposed by others.Both schemes can effectively identify the type of failure,The scheme proposed in this paper has the advantages of high simplicity.