Common-mode outage modelling for composite system reliability assessment using sequential monte carlo simulation technique

Abstract

The reliability assessment of composite generation and transmission systems now-a-days has drawn prime interest in the area of power system plamung. designing and evaluation of reliability. As the demand of the modem society is to have electrical energy as economically as possible with a specified degree of reliability, therefore, there is a significant need to assess the reliability of the composite systems. To evaluate the specified reliability of the composite systems it is necessary to include all the operational factors. Power system reliability assessment can be divided into two basic aspects: adequacy and security. Most of the probabilistic techniques presently available for reliability evaluation are in the domain of adequacy assessment. There are two basic techniques available in the literature for reliability evaluation of composite systems: the analytical approach and simulation approach. Analytical approach represents the system by analytical models and evaluate the indices from these models using mathematical solutions. Monte Carlo simulation methods, however, estimate the indices by a simulating the actual process and random behaviour of tile system. When complex operating conditions are involved and! or the number of severe events is relatively large, Monte Carlo methods are often preferable. Power system reliability evaluation by simulation can be applied in two ways: non-sequential or randomly and sequential or chronological order. The available technique for composite generation and transmission system nonnally consider only simultaneous independent outages because usually the conunon.mode failure rate is small i.e. typical values only of the order of 10% of independent failure rates. But such failures might have severe consequence on the system performance. Many utilities are, tllereforc now using common-mode representations for composite system adequacy analysis. AltllOugh the state space transition diagram for conunon-mode outages are well established. But they can only be utilized in random or non-sequential simulation not in sequential simulation. In case of conunon.mode outage. several departure transition may occur from each state, then it is difficult to predict the next transition. To overcome this difficulty a new approach has been developed in this research. This new algorithm is accommodated in the sequential simulation procedmes to evaluate power system with common-mode failures. Several conunon-mode outage groups are considered and thdr effect on reliability indices are shown in tlJis thesis. So the inadequacies associated with common-mode outages in a composite power system are higWighted more accurately in this thesis. Therefore. the results of such a study arc of great importance to the system planner and operator during the design and operation phases of a power system for more exhaustive analysis. In this research IEEE-IUS is evaluated using sequential Monte Carlo simulation technique for numerical evaluation.