Reliability evaluation of a small area in a composite power system using branch-cutting method and load uncertainty

In many applications, the requirements of static data and large computation times are still major concerns. This paper presents a practical equivalent model of a small area in a large scale system which needs less statistical data of system equipments with acceptable level of accuracy. The proposed technique is designated as the branch-cutting method in which tie lines between the area of interest (AI) and the other parts of the network are cut and the network behavior is modeled with some load and generating units in marginal load points. The load at marginal load points is represented as a multi state load model with the associated state probability. Load uncertainty is modeled using the multi state load model considering the correlation between the load curves of marginal points. The applicability of the proposed technique is illustrated using Iran Power Network and results are presented and compared for various cases