The influence of topology changes on inter-area oscillation modes and mode shapes

TitleThe influence of topology changes on inter-area oscillation modes and mode shapes
Publication TypeConference Paper
Year of Publication2011
AuthorsYousu Chen, Jason C Fuller, Ruisheng Diao, Ning Zhou, Zhenyu Huang, Francis K Tuffner
Conference NameIEEE Power and Energy Society (PES) General Meeting
Date Published07/2011
Conference LocationDetroit, MI, USA
ISBN Number978-1-4577-1000-1
KeywordsAA07-001, AARD, Automatic Switchable Network (ASN), damping, power grid operations, Power system stability, WECC

The topology of a power grid network is a piece of critical information for power grid operations. Different power grid topologies can change grid characteristics, inter-area oscillation modes, mode shapes, and even the robustness of the power system. This paper presents some preliminary study results, based on an approved WECC operating case and a modified low damping WECC system, to show the impact of topology changes resulting from N-1 contingencies on power system modes and mode shapes. The results show that topology changes can have very different impact on modal properties in a power system: some result in an unstable situation, while others can improve small signal stability. For the former, the studies show about a 4.5% damping reduction, so a 5% damping margin would be required to ensure the system can sustain the contingencies. For the latter, those topology changes could be used as a control method to improve small signal stability. Mode shapes normally do not change when there is an N-1 topology change. These observations suggest that the inclusion of topological information is useful for improving the accuracy and effectiveness of power system control schemes.