Research Of Models & Algorithm For Bulk Power System Reliability Assessment Using Monte Carlo Methods

With the increasing of contradiction between supply and demand of electric power as well as advancing of power market mechanism, the application of quantitative reliability evaluation in electric power systems has now evolved to the point at which most utilities use these techniques in one or more areas of their planning, design, and operation. However, most of the techniques in use are based on analytical models and resulting analytical evaluation procedures. Improvements and availability of high-speed computers with large-capacity storage have created the opportunity to analyze many of these reliability problems using stochastic simulation methods and made Monte Carlo simulation a preferable option for many power system reliability applications. With the study of the existing models and algorithms for power system reliability evaluation and the nonce application of Monte Carlo simulation to reliability engineering, this thesis is work on Models and Algorithm for Bulk power system reliability assessment considering many practical factors by Monte Carlo simulation. The main results are as follows:1. For Bulk Power System reliability assessments, Monte Carlo system state simulation method is utilized to sample system state and Dagger Sampling is used for reducing sampling variance. Making a contingency analyze is involving DC power flow calculation, Depth-first Search for recognise of system islanding, and load curtailment calculation. The program based on models and algorithms above is developed and its effectiveness and availability are verified from the test on the IEEE RTS and RBTS. 2. Study the question for considering optimal load curtailment in bulk power system adequacy evaluation. A minimization model of load curtailment is utilized for the contingency states which may have load curtailment. In order to calculate realistic bus indexes, two practical load curtailment philosophies are incorporated in the minimization model of load curtailment, which is achieved in computer program developed for bulk power system reliability evaluation. The minimization model of load curtailment, correlated algorithms, and flow chart of program are given in this paper. The effectiveness and availability of the model are verified from two case studies.3. Study the question for incorporation of the annual load curve and calculating annual indices to assess the adequacy of Bulk power system. The cluster technique is used to create a multi-step model of the annual load curve, and the annual reliability indices can be obtained by weighting the annualized indices for each load level by the load step probability. Case studies show the effect of the number of steps in a load Mode, and thatdifferent load level steps make different contributions to the total annual indices. 4. Study the question for incorporating weather effects in bulk power system adequacy evaluation. A transmission line model considering diverse weather condition is constructed. Using Monte Carlo method to sample region-divided weather state, the method in this paper can recognize the situation in which transmission lines traverse several geographical regions which undergo different weather conditions. Finally, case studies using the program developed by authors show that considering of weather effects has a great importance for system adequacy comparing with neglecting them.