Reactive Power Compensation for Reliability Improvement of Power Systems

This paper investigates the effects of reactive power support limits on power system reliability. In evaluating the reliability of power systems, several load curtailments are caused by voltage limit violations which can be alleviated using reactive power support. The existing methods of estimating the effects of voltage limit violations and reactive power limits do not provide the amount of reactive power support that is required to alleviate the violations. The presented work provides a quantitative measure of reactive power compensation for reliability improvement. This measure is based on constructing a probability distribution function for the required reactive power compensation. Reliability indices of Loss of Load Expectation and Expected Unserved Energy are used to estimate the lack of reactive power support. A non-linear, AC power flow based model is used to accurately represent system load curtailment remedial actions. A state space reduction technique is utilized to reduce the computation time. The proposed method is applied on the modified IEEE RTS and results show the improvement of power system reliability due to reactive power compensation.