Study On The Power System Operational Reliability Evaluation Based On The Theory Of The Risk

As the scale and capacity of power system and the length of the transmission line is increasing, the problem of the power system reliability problem is increasing prominently, especially the traditional reliability evaluation can only reflect the system reliability level for a long time, can not predict the possibility of accident and its severity in the short term, it is necessary to study the short-term risk assessment theory in order to meet the needs of the electric power system short-term reliability evaluation.Combining with the characteristics of operational reliability, a time-varying reliability model of component which suitable for operational risk probabilistic evaluation is established in this thesis based on traditional reliability evaluation theory and method. Namely introducing the component instantaneous state probability based on markov process; Introducing the outage factors of components based on operating conditions and the outage rate models of components based on the single operating and multi operating conditions are theoretically established.And then introduced the selection method of system status:state enumeration method and simulation method. The difference between the two methods is the access methods and its probability distribution of random access method. State enumeration method with the method of fault state enumeration acquisition system random state, and through the analytical method to calculate the probability distribution of the fault state; Simulation method usually refers to the monte carlo method, through random sampling system for random state, based on sample statistics random state occurrence frequency, and then estimate the probability of system random state.Then introduces the basic link of the system state analysis, the power flow calculation of the system, power generation scheduling and cutting load theory, which providing theoretical basis for system reliability assessment process.Aiming at the fault of traditional reliability indices, this thesis construct the index system of operational risk from three aspects that is expected interruption demand,the off-limit extent and the probability of system state. These indicators can reflect the probability of system accdient and its severity in the short term and can reflect the system in real-time operation risk level completely.Finally, using the IEEE-RTS79system as example to verify the effectiveness of the proposed reliability model and the reliability index of risk, the system’s risk can be reflected objectively.