Reliability Analysis Of HVDC System Based On Weibull Distribution Simulation Method

With the development of power system and the increasing power load, the advantage of HVDC transmission in high voltage、large capacity and long distance transmission has become increasingly prominent. Because of the complexity and particularity of these projects, it is very important to improve the reliability of HVDC transmission technology. HVDC reliability has been an important topic in the study of the reliability, this paper based on the results of previous studies, Weibull distribution function is applied to the reliability research of HVDC transmission system. We established the subsystem failure rate bathtub curve and Weibull distribution reliability function, by using a sequential Monte Carlo simulation method for HVDC transmission system reliability is evaluated. This paper mainly completed the following aspects of the work:Firstly, the structure and operation mode of HVDC transmission system are studied in this paper. Based on the dividing principle of HVDC transmission system, the subsystem of HVDC transmission system is divided; Based on the reliability parameters of the system components, the reliability evaluation index of HVDC system is established.Secondly, this paper introduces the mathematical theory of Markov and the establishment method of state space diagram and the calculation process of the state transition rate. According to the division of the subsystem of HVDC transmission system, each subsystem state space diagram and equivalent model were established, Through the combination of the equivalent model of each subsystem, the HVDC system state space diagram and equivalent model were established. Based on the Eel River project execution statistics, according to the establishment of HVDC transmission system state space diagram and equivalent model, we assessed reliability evaluation index on the Eel River Engineering.Thirdly, this Weibull distribution function will be introduced to the Monte Carlo simulation method to establish the reliability model. This paper introduced the probability density function and failure rate function of the three parameter Weibull function and analysed the influence of three parameters to Weibull distribution graph. Introduced the estimation of Weibull function parameters in detail:image method, least square method and maximum likelihood estimation. Sequential Monte Carlo simulation method usually has two kinds of sampling methods:component state duration sampling method and interval sampling method. On the base of two sampling method of flow chart, the two kinds of methods were compared and analyzed.Finally, based on the statistical data of Eel River project, using the proposed Monte Carlo Weibull distribution function based on the improved simulation method to evaluate the reliability of engineering. Eel River project of the system failure rate bathtub curve model were established, combining with the repair rate model of subsystem, to sample subsystem operation data in the MATLAB programming; The running state data of subsystem are combined to simulate the running state of Eel River project system and to calculate the reliability index. The result will be compared with the exponential distribution based on Monte Carlo simulation calculation results and data statistics of Eel River project operation, analysis the advantages and disadvantages of the feasibility of the method.