Voltage sag vulnerability study in power system planning

In current power system planning practice, system security and reliability issues are addressed. Deregulation of the electric power industry has forced utilities to evaluate the cost-benefit implications of providing acceptable quality services for customers. In this study, the fault position method is used to study the effects of network changes on the area of vulnerability of voltage sag problems at some industrial parks that have various types of sensitive loads. Comparison of exposed areas before and after a major system expansion is presented. Knowing which primary components are within the vulnerable area is helpful from system planning and operations points of view.