Research On Reliability Detection And Risk Assessment Of Relay Protection System

With the construction of intelligent substation in China,intelligent electronic equipment and virtual terminal connection are introduced in intelligent substation.The fault analysis and location of the secondary system of intelligent substation is faced with such problems as large data scale and complex fault mechanism.The traditional relay protection tester can not test the hidden fault of the secondary system.Therefore,it is necessary to conduct in-depth research on the interaction between intelligent electronic devices in the reliability testing and risk assessment of relay protection system.Based on IEC61850 protocol,this paper studies the reliability test and risk assessment of relay protection system.First,aiming at the relay protection commissioning and acceptance in substation operation and maintenance,this paper proposes a fault detection scheme of intelligent substation secondary system based on self-established fault set for substation operation and maintenance.According to the characteristics of sampling digitization in digital metering system of intelligent substation,the establishment method of self-set fault set is put forward.The solution can complete the simulation of GOOSE and SV service functions,so as to realize the reliability testing of the protection device and secondary loop.At last,a 220 k V substation loss of voltage accident was taken as an example to establish a self-designed fault set,and the detection results were analyzed.Second,aiming at the defect analysis and treatment of relay protection system in substation operation and maintenance,a risk assessment model of relay protection system considering risk diffusion is established.Combined with secondary-system information flow and protection logic,the protection system dependent network model is established.Subsequently,a secondary-system risk diffusion model is established according to the risk diffusion process caused by the failure of certain devices.Finally,the characteristics of secondary system risk diffusion are obtained by simulation analysis,and the risk assessment is carried out considering system scale,risk recovery parameters and misoperations.This method can effectively improve the efficiency of relay protection.Third,to further improve the reliability of substation relay system,a fault location method based on matrix algorithm and BP neural network is proposed.First,the logical node description model and matrix criterion of substation secondary system are obtained by combing and abstracting the interaction logic of actual substation secondary system information physical system.Then,the matrix algorithm can be used to quickly determine the suspicious fault range when obtaining the secondary system topology association and interaction information.Moreover,the fitting ability of BP neural network is used to narrow the fault location range and improve the location accuracy.Finally,the secondary system failure event is taken as an example,and the analysis process of the secondary system fault location based on matrix algorithm and BP neural network is demonstrated.Compared with the combined recurrent neural network and convolutional neural network,the proposed method has higher diagnostic accuracy.Finally,the main research contents and results were summarized.