Reliability Evaluation For AC/DC Systems Using Hybrid Method

With the development of High Voltage Directed Current (HVDC) transmission technologies, more and more HVAC/HVDC hybrid transmission systems are put into service recently, so, it has important significance for researching how to evaluate its reliability. AC/DC system has a mass of elements and complexity calculation conditions, which lead to the difficulty of its reliability evaluation.In this paper, to the problem of AC/DC system’s reliability evaluation, after analyzing the merits and demerits of FD Analytics method and Monte Carlo simulation Method respectively, a comprehensive method combing the above two basic methods is presented and employed in the reliability evaluation of AC/DC system. Firstly, the paper proposes a AC/DC system reliability evaluation model and calculates its basic reliability indices, Multi-terminal DC (MTDC) system is considered in the model. Secondly, DC power flow method and AC-DC iterative continuation power flow method are adopted to analy the states of the system and calculate the adjustment. Lastly, using comprehensive method to simulate states of AC/DC system and calculate the reliability indices. In order to reflect the actual operation turely, progressive overload elimination method based on sensitivity technique method are used for the problem of line PF beyond the limit when the elements of system failure, which realize reliability and economy effectively. The modified IEEE-24and IEEE-30bus test system are used to verify the presented approach.