Research About The Relay Protection Key Parts Hidden Failure Diagnosis Method And Monitoring Technique

Nowadays size of the grid is increasing, the network continuous access to new energy, the new high-power electronic devices continue to put into operation, these circumstances led to the gradual increase of grid operation mode. As the key defense, the relay protection system is facing a big challenge. Protection hidden failure has these features: long incubation period, wide spread rang and large degree of harm. So, hidden failure becomes a big risk that threaten the safe operation of gird. How to troubleshoot hidden failures effectively is important.To do this, the paper analyzes the hidden failure generation and outbreak mechanism, focus on protection setting improper issues. Compares the advantages and disadvantages of the current hidden failure research methods, proposes a new thought that using disturbance information to analyze operation features of protection devices. The method not only solves the defect that data is difficult to obtain, but also enable real-time analysis of the protection device dynamic characteristics. Based on the idea, this paper proposes a diagnosis method aimed at distance protection measurement loop hidden failure. Aiming at simple network and network with branch lines, analyzes measurement values constraint relations among different protection devices in the fault duration. Deduces constraints discriminants and thresholds, by substituting measure impedance and composing the results, the purpose of positioning failure device can be achieved. According to the problem of protection measure impedance sync issue, put forward a processing method by using measure impedance on faults steady moment. And uses numerical examples demonstrate the effectiveness of diagnostic methods.Aiming at branch coefficient inappropriate choice problem during protection setting process, this paper deduces the accurate representation of branch coefficient, and builds a verification method. Using phase current and zero sequence current flowing through the bus in fault duration time, the backup protection branch coefficient verification under current operation mode could be achieve. The proposed method is verified by simulation, it is more sensitive than existing verification methods.Aiming at protection export platen setting error issue. This paper proposes a structure of monitoring terminal device. It could turn platen physical displacement into an electrical signal, achieve the purpose of monitoring platen position. Base on this monitoring method, this paper proposes a smart verification method. Through the relationship between relay protection and automatic devices pressed board setting rules and state of primary devices, the primary device-pressed board position rule-base could be generated. After the breaker switching operation at the substation, the breaker state could be used to identify component state, then the corresponding rules could be choose from rule-base. In addition, use platen position monitoring device to identify the real-time status of platen, and compare with the current rules, enabling smart verification of platen position. The feasibility and effectiveness of the method has been verified through practical application.This paper is funded by Chongqing province Scientific and technological project:(cstc2012gg-yyjs B90003)intelligent substation online fault diagnosis technology and devices.