Research On Real-time Reliability And Risk Assessment Of Relay Protection In Intelligent Substation

China has become the country with the largest number of smart substations.In the intelligent substation,a large number of new technologies such as Gigabit Ethernet high-speed communication,microsecond high-precision synchronous sampling,photoelectric transformer,and three-layer two-network are adopted.Compared with the traditional substation,the secondary system structure of the intelligent substation is distributed.This solution has a great impact on the reliability analysis and evaluation of relay protection systems.Therefore,these new technologies have brought great changes to the power system,and their reliability issues have also received extensive attention.The digitization of the whole station information of the intelligent substation provides the basis for the realization of distributed relay protection,and also provides the possibility of real-time operation status information analysis and system level status identification and evaluation at the relay protection device level.This paper starts with IEC61850 and deeply analyzes the message structure of Generic Object Oriented Substation Event(GOOSE)messages and Sampled Value(SV)messages.Substation Configuration Description(SCD)The content is deconstructed to obtain the response relationship between the SCD file and the two types of messages,and an intuitive visual structure diagram is generated on this basis.On the basis of the internal association structure of the file,the automatic extraction of the abnormal information of the protection device is realized,real-time collection and analysis of the online detection data is realized,and the information is classified,and the reliability index available for calculation is obtained.At the same time,the Markov method is used to calculate the reliability of the relay protection system,and the excessive space state leads to the computational complexity.The reliability of the relay protection device is calculated by the Markov method,and then the reliability of the relay protection system is calculated by the GO method.Model and GO method relay protection system reliability analysis method.This method enables field operators to get more real-time feedback on the operating status of the relay protection device and system.Not only saves time,but also saves the complicated and inaccurate estimation process.Secondly,aiming at the small sample problem in the initial stage of relay protection device,a gray estimation method based on three-parameter Weibull distribution is proposed.By comparing the example calculation with other methods,it is proved that the new method can calculate the reliability parameters of the small sample relay protection device,and the calculation speed is faster while ensuring high precision.Finally,based on the analysis of the internal structure of the insurance system file,the automatic extraction of the abnormal information of the protection device is realized.According to the failure mode and the reliability analysis method FMEA,the risk evaluation index of the online state of the relay protection device is proposed.For the quantitative assessment of the real-time status of the relay protection device and system,the actual operation data of the protection device is taken as an example to verify the effectiveness of the method.