Multi-dimensional load modeling in power system reliability evaluation

The purpose of this investigation is to introduce a new approach to model the bus load correlation in performing a reliability analysis of composite systems. This is achieved by considering different time varying load curves (referred to as the multi-dimensional load profile), corresponding to different types of loads in a composite generation and transmission system and applying the contingency enumeration technique for reliability analysis. The proposed technique determines the appropriate load levels and the corresponding geographical distribution of the loads among different buses (load states) at which the contingency analysis needs to be performed.; TRELSS (Transmission Reliability Analysis of Large Scale Systems), a software package developed by EPRI, is used to perform the contingency analysis on the IEEE 25 bus Modified Reliability Test System. The adequacy indices Frequency of Load Curtailment (FLC), Probability of Load Curtailment (PLC) and Expected Unserved Energy (EUE) are evaluated in this investigation. The accuracy of the results obtained by the proposed load model is determined by comparisons to results obtained by performing a detailed hour by hour contingency analysis of the system. It is shown that the proposed technique produces better results than the existing methods without spending excessive computational time. A set of algorithms and corresponding programs in MATLAB which use TRELSS for contingency enumeration and incorporates the proposed load modeling procedure is developed.