Voltage stability improvement technique by optimal transformer tap changer setting using evolutionary programming technique

Reactive power loading has been known to be one of the factors, which caused a power system to be in a stressed condition. As a result, system may be operating close to its voltage stability limit leading to voltage decay at a particular load bus. Hence, some measures should be taken in order to support for the reactive power loading and thus improves the voltage stability condition of the system. This paper presents an optimal transformer tap changer setting based on Evolutionary Programming (EP) optimization technique for voltage stability improvement in power system. The objective function is to increase the voltage stability condition utilizing a line-based index as the fitness function. Improvement of voltage stability condition is indicated by the reduction in the values of this index. Results obtained from the test implied the new transformer tap changer setting values for voltage stability improvement in the system. It was revealed that the use of EP optimizing technique for improving the voltage stability condition using the line index as the fitness is simple, fast, accurate and reliable; indicating it as a feasible technique for further reactive power planning scheme. The proposed optimization technique was validated on the IEEE Reliability Test System (IEEERTS) and results are included to realize the effectiveness of the proposed EP optimization technique.