Problems of voltage collapse, voltage stability, unsatisfactory voltages, and network branch over loading are caused by contingencies in network. Contingency effects have to be estimated in order to maintain system security. Stability and security of system are improved by this measure. Fuzzy logic composite criteria are used in this paper to rank contingencies in network. Effect of masking is also eliminated by this. Ranking of network contingency is evaluated using generators reactive power and load buses output at post-contingency voltage stability indices in proposed fuzzy method. Under network contingency and normal operation, problems of OPF are solved by using proposed memetic differential evolution algorithm (MDE). Active power output of generators optimum value is computed by proposed MDE algorithm. Reactive power control devices are adjusted. IEEE 30 bus test system is used for simulation. Results of simulation are compared with existing methods in literature. In computing optimal solution, robustness of proposed method is validated and tested by various cases. When compared with classical DE and other methods in literature, better results are produced by memetic differential evolution algorithm.
Volume 11 | Issue 11