Reliability and Sensitivity Analysis of Composite Power Systems Considering Voltage and Reactive Power Constraints

This work investigates the effects of voltage and reactive power constraints on composite system reliability indices. Four indices have been used to assess the sensitivity of load curtailments to voltage and reactive power constraints. Further, expressions to evaluate the sensitivity of the severity indices with respect to the voltage and reactive power constraints have been developed. Extensive simulations on the IEEE Reliability Test System (RTS) based on the AC power flow model were carried out to correlate the violations of these limits and the loading level of the system. A non-linear, AC power flow based model has been used to accurately represent system redispatch. A state space reduction technique has been utilised to reduce the computation time. A comparison between redispatch models using AC and DC power flow has been provided to illustrate the benefits of the more accurate AC flow model and to investigate the effects of the voltage and reactive power constraints on reliability indices.