Approach on optimal generation and load control for enhancing voltage stability margin

In the condition of suddenly increasing load such as summer peak load, contingencies and so on, it is important to ensure voltage stability margin (VSM) for preventing voltage instability as well as voltage collapse. To support active power on the system, some facilities for weak buses, such as ULTC, SC, FACTS (flexible AC transmission system), are controlled and the dispatch of committing generator outputs is also to be a good methods. Moreover DSM (demand side management) is considered in other side for system security and stability recently. DLC (direct load control) is especially effective and simple among a variable of DSM methods. This paper introduces a novel approach considering not only the generation side but also the demand side at a time. In other words, optimal economic dispatch and load curtailment are used for ensuring voltage stability. To do this, loading factor and generating factor are contained in objective function and load model, namely ZIP model, is also considered in equality constraint. Generation power and curtailed load, which is able to make stable state, are solved by an application tool called GAMS and the modified IEEE 6-bus test system is used in this paper.