A Fast Loop-Based Algorithm for Automatic Contingency Selection

Abstract

In order to speed up on-line security assessment, a fast loop-based automatic contingency selection algorithm is presented in this paper. A linearized active power flow model is built up and loop analysis method with introduction of series potential compensation is used to compute the distribution of the flows after occurance of outages, thereby the change of active power performance index due to outage is calculated, and from which an outage list is constructed. Instead of using detailed AC (or DC) load flow calculation for each outage case, only one m-dimensiona1 forward/backward substitution solution is required to construct the outage list, where m is the number of loops which is much less than the number of buses. Therefore, this method is very fast in speed in contrast with the node-based method. Several digital examples are carried out and the calculated results show that the proposed method is more accurate than that by using a single P-Q iteration of FDLF, at the same time, the calculation speed is hundreds of times faster than the latter. Simultaneous multi-outages can also be simulated and their formulas for calculation are also given.