Voltage security evaluation by a new framework based on the load domain margin and continuation method

Voltage security is one of the vital concerns especially in competitive electricity markets due to the delineation of the system controller and generation owner. There is a perceived increase in the frequency at which power system operators are encountering high stress in bulk transmission systems and the corresponding need to improve security monitoring of these networks. This paper presents a new framework including a comprehensive model and an efficient continuation method to determine voltage security status of the power system under varying network conditions, loading conditions and generation patterns. Reactive power limits of the generators and various tap changer control mechanisms have been considered in the framework. Moreover, the proposed framework is capable to evaluate voltage stability margin or instability depth of the power system. Results of testing the proposed method on two practical systems, power networks of New Zealand and Iran, confirm the validity of developed approach.