Study On The Reliability Simulation Of Substation Taking Into Consideration The Fault Disposing Process

Substation is the core component of the power system and its reliable operation level plays a vital role in the safe and stable operation of the whole power grid.In this paper,the primary system and relay protection system of substation are taken as the research objects,and their reliability analysis is carried out.The main contents and innovative achievements are reflected in the following aspects:(1)A reliability evaluation scheme of substation primary system considering fault treatment process is constructed.In this paper,the process of fault clearance and fault restoration after component fault is considered,and the"four-state"model of components is proposed,which is respectively the normal state,the state that the fault has not been removed after the occurrence of fault,the state that the fault has not been restored after the completion of fault clearance and the state that the repair has not been completed after the restoration operation.In view of the non-independence of the circuit breaker's rejection,for the circuit breakers that need to trip in the fault clearance stage,a normal quitting state is added on the basis of the"four-state"model,namely the "five-state"model.Based on the non-sequential Monte Carlo method,this paper successively simulates the fault clearance and fault restoration operation corresponding to each state combination of components,and analyzes the corresponding fault consequences respectively,and statistics the reliability index of the entire substation primary system including the transformer and main wiring of multiple voltage levels.Finally,through the comparison and analysis of calculation examples,it is proved that the scheme can reflect the reliability level of substation more accurately.(2)From the integral view of substation primary system and protection system,the reliability evaluation algorithm of substation considering protection failure is proposed.Firstly,according to the configuration mode and information flow path of line protection,transformer protection and busbar protection,this paper uses reliability block diagram method to obtain the fault-free misoperation rate,non-selective misoperation rate and rejection rate.On this basis,two methods are adopted to account the impact of protection system.Method 1 correctes the reliability parameters of circuit breakers according to the state mapping relationship between the protection systems and primary equipment.Method 2 simulates the operation states of primary equipment and protection systems at the same time.Finally,the effectiveness of the two methods is verified through the comparative analysis of substation examples.(3)Evaluate the importance of substation components.Using the graphical expression method of sensitivity analysis,this paper calculated the sensitivity index of reliability index after fault clearance and after fault restoration to active failure rate,passive rate and rejection rate of primary equipment.The results can provide reference for works,such as substation planning and design,operation maintenance,and aging update.