Research On Reliability Evaluation Of The Composite Generation And Transmission System Based On The Hybrid Method And The Contrl Variable Method

With the increasing number of electric generator of large capacity and the UHV AC demonstration project successfully put into operation, power grid construction in our country has reached a whole new level. Especially after the12th five-year plan, State Grid Corporation further accelerated the subsequent construction of the UHV AC project. Therefore, further improving the reliability of the composite generation and transmission system has inevitably placed in front of us.Being an important part of reliability evaluation for power system, the reliability evaluation of generation and transmission system involves various electrical equipments and complicated structures. Its fault mode is always overlapped and has a very important impact on load point reliability. Therefore, the reliability evaluation of generation and transmission system has become one of the important research topics of the power system.In this paper, on the basis of previous work, the reliability evaluation of generation and transmission systems is further researched and discussed. Some corresponding improvement algorithm has been put forward. The main content is as follows:(1)The basic concept of reliability evaluation of composite generation and transmission system, together with the course and prospect of development has been introduced. It summarizes various methods of reliability evaluation of composite generation and transmission system, and their application status in power system reliability evaluation.(2)The basic principle of analytic method and Monte Carlo method has been summarized, on the basis of which a reliability assessment method based on the hybrid method and the controlling variables method has been proposed. Sampling was carried out on the system by using the Monte Carlo method, after which rapid analytical judgment is adopted to the system. Then, the condition that does not need cutting load is eliminated, and the condition that needs cutting load is adjusted. The corresponding reliability index is calculated combined with the control variables. Thus it can greatly reduce the calculation time of reliability index and accelerate the speed of convergence.(3)The mathematical model of reliability evaluation of composite generation and transmission system has been established. The corresponding algorithm is studied. The neglect of DC power flow method without reactive power and active linear optimization method based on simplex method in the trend is adopted. Reliability evaluation program has been composed according to the proposed algorithm. Not only can the program be used in the composite generation and transmission system for adequacy assessment and reliability evaluation, it can also be adopted in analysis of power system and transmission system on the reliability of the whole power system.(4) The reliability index of the system IEEE-RTS79has been evaluated with the above method respectively. The results show that:with the same precision, this method has obvious advantages in speeding up the calculation of reliability index.