Sensitivity analysis and contingency evaluation by adjoint network-based methods

Abstract

Tellegen's theorem and the concept of adjoint networks have been applied to power systems by making use of the DC load flow model and/or by considering only first-order sensitivity analysis. In this paper we make use of these tools to develop generalized, higher-order AC sensitivity formulae. Of special relevance are the formulae directly applicable to contingency simulation, namely to the simulation of branch outages. Single and multiple branch outages are considered. We test for the existence of solution and, if it exists, a non-iterative solution is computed. Branch-oriented and bus-oriented formulae are presented. We also describe how to handle PV buses in the adjoint network context. The approach proposed leads to acceptable good results and is robust. It also gives analytic insight into the problem of load flow solution and system response to branch perturbations.