Sensitivity Analysis of Dynamic Stability Indicators in Power Systems

Real time stability evaluation and preventive scheduling in power systems offers many challenges in a stressed power system. Through fast simulation of contingencies in real time it is possible to extract suitable information from the data and develop reliable metrics or indices to evaluate proximity of the system to an unstable condition. In this chapter we review the recent applications of the trajectory sensitivity analysis (TSA) technique in developing such indicators. Trajectory sensitivities can be used to compute critical parameters such as clearing time of circuit breakers, tie line flow, etc. in a power system by developing suitable norms for ease of interpretation. Alternatively it can be used along with the notion of Principal Singular Surfaces (PSS) to detect mode of instability (MOI). The TSA technique has the advantage that model complexity is not a limitation and the sensitivities are computed numerically. Suitable metrics are developed from these sensitivities. In addition to computing critical parameters, the TSA technique can be extended to do preventive rescheduling. A brief discussion of other applications of TSA is included as well as future areas of research.