Reliability And Risk Assessment Of Secondary System In Smart Substation

The secondary system is the key element of the design,construction,technical innovation and management of intelligent substation,and the reliability evaluation of power system is an important content of power grid management.With the development of study on secondary system in smart substation,traditional reliability index and methods can't fully reflect the operation status of the secondary systems,the real-time reliability and risk assessment of the secondary system gradually draw more attention.The effects on power grid and reliability of electric power system are studied.Then,the relative importance of the key components of the protection system is studied using the entropy weight method.Finally,select the appropriate indicators as a consequence of the failure of the protection system,and then quantify the operational risks of different protection systems.In this paper,the reliability of the protection system and the influence of the failure of the protection system on the power system are studied.Using Markov state transition method,the availability of each component protection system is calculated,combined with the actual work of the protection system,steady malfunction state of protection system is achieved.Redundancy of protection system decrease rejection rate to 10-8,which can effectively avoid potential harm caused by rejection.In this paper,the outage condition of the protection system is analyzed qualitatively and quantitatively,and the influence of different failure modes on the reliability of the two buses is quantitatively studied.This paper studies the operation risk of different kinds of protection systems.According to the failure mode of protection system,potential harm of the potential consequences of 220kV line protection system,220kV bus protection system,transformer protection system and 110kV bus protection system failure is analyzed,real-time failure frequency of electric system and severity comprehensively define the consequences of the different failure modes of protection system,combined with the probability of occurrence of different failure modes,achieving operation risk protection.It is considered that the 220kV bus protection system and the main transformer protection system have the highest risk.Under the premise that a set of protection has been shut down,the real time risk of the protection system has been greatly improved,and the potential risk of the protection system has been dominated.The real-time reliability of the secondary systems is studied in this paper.The intelligent substation is decomposed into a set of functions and sub-functions,and the structure entropy weight method is used to transform the expert order into a normalized weight.Definition and formula of devices' disturbance and secondary systems' integrity is given,and then analyzes the result when certain equipment becomes faulted,analyzes the secondary sets of equipment failure after the normal operation of the sub function,then calculate equipment disturbance degree and system's instant integrity,which characterize the real-time reliability of two system.