CYCLIC SECURITY ANALYSIS FOR SECURITY CONSTRAINED OPTIMAL POWER-FLOW

The security of power system may be enhanced by supplementing optimal power flow model with a N-1 security rule (respect of voltage and powe r flaw limits after any single line or generating unit outage). Includ ing in the Optimal Power Flow model a Security Analysis a Security Con straints Optimal Power Flow model is obtained. This paper deals with t he application of a new contingency screening model to speed-up the Se curity Constrained Optimal Power Flow (SCOPF), which makes possible th e on-line applications. The SCOPF resolution process is an iterative o ne. A cyclic contingency selection model is designed in order to take advantage of the specific characteristics of the optimal power flow pr oblem, such as the lower variations of the control variables between t he SCOPF iterations. The cyclic security approach takes the results of a security analysis carried out at time t(k) and extracts data for us e by another security analysis at time t(k)+Delta t in order to reduce the computational burden. Tests performed show that the inclusion in the OFF of the proposed cyclic security procedure efficiently produces more secure conditions against critical contingencies and considerabl y speeds up the security constraint optimal power flow.