A composite framework for synchronous and voltage stability in power systems

Energy function methods have been used to separately assess both synchronous stability and quasi-static voltage security of power systems. The authors demonstrate the linkage between the different applications. The energy function used for synchronous stability is based upon either the classical model or the structure preserving model, with the stability boundary determined by energy of the controlling unstable equilibrium point (UEP). For the voltage stability problem, the use of the structure preserving model is essential. The main difference between two applications lies in the system models used for calculating the UEPs and system trajectories. These differences are based upon the different time frames of the two problems. A new framework for unifying the two separate applications is explored