Design of secondary voltage and stability controls with multiple control objectives

The purpose of the proposed research is to design a Decentralized Voltage/Stability Monitoring and Control System to counteract voltage violations and the impact of disturbances/contingencies on power system voltage stability. A decentralized voltage and stability control system is designed to coordinate the controls of the local secondary voltage control devices and necessary load shedding without requiring information about the rest of the system.;A brief review of the voltage stability monitoring and control applications in power systems is presented. The existing secondary voltage control applications rely on the automatic/manual control of individual secondary voltage control devices whose time constants are approximately three minutes in length. The design of a fast secondary voltage/stability control system is important to mitigate the impact of disturbances on system stability. A literature survey of the applications in the Wide Area Measurement System (WAMS) is performed. Based on the infrastructure of the WAMS, upgrades in voltage and stability controls are one of the most important options.;The voltage/stability control can be formulated as a multi-objective optimization problem. The control objectives include, but are not limited to: minimization of system active/reactive losses; maximization of the system stability margin; and minimization of the control actions. The constraints of the optimization problem depend on the specifications of the actual system components.;For the first time, margin sensitivities of the control actions are included in the control formulation. The concept of using margin sensitivity to evaluate the post-control load margin is presented as a fast and accurate way to assess potential voltage and stability control options. A system decomposition procedure is designed to define the disturbance-affected zone as an independent control subsystem. A normal constraint algorithm is adopted to identify the most suitable control solution in a shorter timeline than the typical utility voltage-control practice. Both steady-state and dynamic simulations are performed to compare the proposed system with typical utility control practices.