Stochastic reactive power planning in distribution systems considering wind turbines electric power variations
Optimal reactive power planning in the distribution systems is a very significant issue which can reduces the amount of power losses and increase the power quality of the electrical services, effectively. Nevertheless, by the rapid growth of the renewable power sources especially wind turbines (WTs) this problem has been affected greatly. The stochastic nature of WT and its output variable power has become a challenging issue for optimal reactive power planning of the distribution systems such as capacitor placement problem. In this way, this paper suggests a new stochastic framework based on point estimate method (PEM) to solve the capacitor placement problem considering several WTs in the system. The PEM makes use of the first few statistical data of the random variables to find the expected value of the output, here the system total costs. The uncertainties of the forecast error in the WT output power as well as the active and reactive loads are modeled in the proposed framework. Meanwhile, a powerful optimization algorithm called Krill Herd (KH) algorithm is used to solve this problem suitably. The performance of the proposed method is examined on the IEEE distribution test system.