Reliability Evaluation Of Secondary System Of Smart Substation

The intelligent substation is the key link of the smart grid,which is the convergence point of the power system "information flow,physical flow and energy flow".The effective reliability evaluation of the intelligent substation is of great significance to guide the optimal configuration of the intelligent substation and the maintenance.This paper focuses on the influence of the information message in the communication network on the reliability of the intelligent substation,and puts forward a reliability evaluation algorithm for the secondary system of the intelligent substation.First,in order to quantify the reliability level of the message,a message reliability evaluation formula with message transmission delay as input is proposed.The D2-1 type intelligent substation centralized protection system is used as the evaluation architecture,the influence of the message on the reliability of centralized protection and distributed protection is then analyzed.The virtual network technology can effectively optimize the network traffic distribution and improve the reliability of the intelligent substation was demonstrated through OPNET software simulation.Then,on the basis of the quantitative evaluation formula of the reliability of the proposed message,the influence of the normal operation status of the grid,the fault status of the power grid,the loss of the message and error of the message on the normal operation of the centralized protection are discussed.According to the protection characteristics under the various states and the corresponding protection strategy,the reliability model is established.Finally,a new algorithm for reliability evaluation of secondary system of substation is proposed for the present situation that the reliability evaluation of intelligent substation is mainly focused on the protection system and the reliability evaluation of the whole secondary system is less.Based on the performance difference between the messages under the IEC 61850 standard,the value of the importance of the message is quantitatively determined.In the concept of the importance of the message,index system of the importance of the component,the risk of the component,the importance of the whole network,the average importance of the whole network,the whole network balance importance is established for a variety of network architecture under a variety of functional status of the secondary system for a reliability assessment.