Stability analysis and assessment of integrated power systems using RTDS

Stability is naturally desirable during integrated power system (IPS) operation. A methodology is proposed to analyze and assess IPS stability. Detailed IPS models are simulated on an RTDS real-time simulator and can be completed within a reasonable time frame with the large number of parallel processors on the RTDS. When a system becomes physically unstable, divergent or sustained oscillations appear in the system response after it is disturbed. The stability of the system then is determined by analyzing oscillation modes in the system response using Prony analysis. Based on results from detailed simulation and Prony analysis, an algorithm is developed for the automated approximate detection of stability boundaries. The algorithm is realized in the environment of the RTDS script language and MATLAB. The effectiveness of the automated detection of stability boundaries is demonstrated on a one-machine-infinite-bus (OMIB) system. In a further case study, the stability of an example IPS with different magnitudes of pulsed load switched into the system is studied. The maximum allowable pulse magnitude for a stable system is found as the stability boundary of the IPS. The phase portrait of the system with the maximum allowable pulsed load shows periodic traversals in state space. The periodic traversals plot limit cycles and thus the stability boundary of the example system.