Power System Optimization

Chapter 6Power System Reactive Power Optimization

6.1 Space Decoupling for Reactive Power Optimization

Recently, reactive power dispatch has received ever-increasing interest from electric utilities because of its significant influence on the secure and economic operation of power systems. In order to improve the voltage profile and to decrease the active power losses along the transmission lines under various operating conditions, power system operators can select a number of control tools such as switching reactive power compensators, changing generator voltages, and adjusting transformer tap settings. The objective of optimal reactive power dispatch (ORPD) is to allocate reactive power generation so that the active power transmission loss is minimized and the voltage stability margin is maximized, while satisfying a number of constraints. The problem is a combinatorial optimization problem with various characteristics: multi-objective, multi-uncertainty, multi-restriction, multi-extremum, and nonlinear property. Under real-time circumstances, ORPD algorithms are faced with the challenges of solution quality, response speed, robustness of the start point, infeasibility detection and handling, and discreteness of control variables.

Extensive computational experience indicates that the nonlinear programming technique is a very demanding task, especially for large-scale power systems [206]. An artificial neural network-based approach has been used in a 62-bus network for reactive ...