Secondary voltage control based on estimation of reactive power deficit

In this paper an approach to perform secondary voltage control in the transmission network is proposed. The approach is based on the nonlinear programming and has two main features in comparison with the already proposed approaches. The first feature is that the buses where compensation devices are connected are selected as pilot nodes which will be called control buses (CB´s). The second feature of the proposed approach is that the control variables in the objective function are the required reactive power variations at CB´s. This feature allows formulating the optimization problem which yields the deficit of reactive power independent of the used reactive power sources. The IEEE 39-bus test system is used as case study to illustrate the effectiveness of the proposed approach in centralized and decentralized control.