Voltage control using a combined integer linear programming and rule-based approach

An expert system which combines operators´ dispatching rules and the integer linear programming (LP) routine is designed for voltage control of the Taiwan Power Company. To reach the control actions at one time and to avoid the need of rounding off the control actions for capacitors/inductors and transformer taps, the efficient integer LP routine is developed using the branch-and-bound algorithm. The operators´ heuristic rules and sensitivity factors are used to reduce the number of variables and constraints in the integer LP formulation in order to reduce the computational time and to make the approach feasible in real-time situations. The expert system was applied to correct abnormal voltages during emergency conditions. It was found that the proposed expert system is a valuable aid to system operators for voltage control