Incorporating a fuzzy load model in reliability evaluation of mixed AC-DC supply system: An actual utility case

The uncertainty associated with load forecast is a challenging issue in reliability evaluation and transmission planning. The uncertainty cannot be always represented by a probability distribution. This paper presents a method to include a fuzzy load model in reliability evaluation of mixed AC-DC supply systems. The presented fuzzy load model and three-state probability model for HVDC poles can be easily incorporated into the traditional Monte Carlo simulation process for transmission power supply system reliability assessment. An actual utility planning case is used to demonstrate the application of the presented method. The results indicate that the membership functions of EENS reliability indices can provide a clear insight into the impacts of load forecast uncertainty on system reliability.