Study On Model And Algorithm For Probabilistic Evaluation Of Power System Operational Risk

This dissertation is supported by Special Found of the National Basic Research Program of China (No.2004CB217908) and National Natural Science Foundation of China (No.50607021).With the rapid growth of china's power demand and the implementation of the'west-to-east power transmission, national interconnected network'strategy, the scale of power grid expanding increasingly and the degree of power network interconnected raising continuously, the operational risks of power system have become increasingly prominent. Therefore, study on the advanced theories, models and algorithms of operational risk probabilistic evaluation to achieve the dynamic identification and early risk warning of operational reliability have become a front-subject which urgent needs to solve.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. 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.To improve the accuracy of operational risk evaluation, this dissertation proposes an algorithm of operational risk evaluation which considers the time-variation of component's operational state and the effect of under frequency load shedding. In this algorithm the components are divided into two types, and the time-dependent outage probability of each type is deduced based on daily generation scheduling.Due to the artificial remedial measure is not taken into account in the analysis of failure consequences, and the impact of dispatcher's subjective experience is avoided in the algorithm, the system's risk can be reflected objectively and factually after it encountering disturbances.In addition, the graduation thesis also studies the relationship between system's operation risk and the real-time power price. By the study it concludes that risk management should adopt the result of the operational risk assessment to rectify the real time electrovalence instead of by traditional reliability evaluation result. And then a new risk management strategy considering real-time electricity price is proposed. In this strategy, real-time price factor is brought in risk management to rectify operation risk level so as to improve system operational reliability.