Emergency Adjustments to Var Control Variables to Alleviate Over-Voltages, Under-Voltages,and Generator Var Limit Violations

A method of determining the minimal adjustments to the reactive power (VAR) control variables required to alleviate over-voltages, under-voltages, and generator VAR limit violations has been developed and is presented in this paper. Because the method minimizes the overall adjustments to the control variables, it is particularly suitable for emergency situations. The algorithm uses the sensitivity relationships of power systems to determine the linearized sensitivity relationships linking the dependent and control variables. Then, it uses a dual Linear Programming technique to solve the problem.