Risk Assessment Of Relay Protection Device In Smart Substation

At present,strong smart grid is developing rapidly,and smart substation is the support point of smart grid.On the basis of the IEC61850 communication protocol,the application of intelligent equipment has led to the changes in the system structure,component composition and implementation mode of the relay protection device,which has brought new requirements and challenges to operation and maintenance.Therefore,the study of the risk assessment system applicable to the relay protection device of smart substation is conducive to improving the operation and maintenance efficiency and maintenance benefit of the protection device of smart substation,and ensuring the reliable operation of the power system.Firstly,this paper studies the reliability of relay protection device in smart substation.This paper summarizes the overall architecture of smart substation and the components of relay protection system,and briefly analyzes the networking mode of process layer,information interaction mode of interval layer and different protection configuration schemes.A general markov model is established for each component of the protection device,and the availability of each component is calculated.Based on the reliability block diagram method,the reliability of traditional protection and intelligent station protection is analyzed and calculated.The results show that the availability of bus protection is lower than that of main transformer protection and line protection.Then,this paper studies the risk assessment method of protective device.Based on the risk theory,the risk source of the protective device is analyzed,and the three aspects of element overload,voltage over-limit and load loss are selected to show the influence of the protective device fault on the stable operation and power supply capacity of the substation.Based on the non-sequential monte carlo method,the risk of relay protection device in a 220 k V substation is quantitatively calculated.The results show that the risks of protection devices vary with the main wiring structure,equipment configuration and protection configuration,but the risks of transformer protection devices are the highest in general.Finally,this paper studies the maintenance and replacement strategy of protective devices,and considers economic factors on the basis of reliability and risk assessment.Based on the repairability and loss of maintenance,a failure distribution model considering the influence of maintenance of protective device is established.Based on the three factors of equipment risk,maintenance return and maintenance return.Based on the life cycle cost theory,the annual average cost model of protection device is established from five aspects: investment,operation,overhaul,loss and treatment,and the optimal economic life of a protection device is calculated based on the model.