Use of frequency-scan techniques for subsynchronous-resonance analysis of a practical series-capacitor compensated AC network

Several utilities in the Mid-Continent Area Power Pool (MAPP) have planned to build the MANDAN Project, a proposed series-capacitor compensated 500 kV AC transmission international interconnection to be run from the Dorsey Substation near Winnipeg. Manitoba, Canada, to the Hoskins substation near Norfolk, Nebraska, United States, with intermediate taps in the United States in North Dakota near Valley City and in South Dakota near Huron. The MANDAN project will be the first application of series-capacitor compensation in the eastern United States. The paper describes the results of a frequency-scan study conducted to investigate subsynchronous resonance (SSR) and potential torsional interaction problems associated with 35 turbine-generator units located at 27 generating plants existing and projected in the area traversed by the MANDAN project. Provided in the paper is a description of the frequency-scan technique and its use in analysis of SSR problems, network model used, system and machine data required, MANDAN line simulation, and study methodology and case list developed particularly for the MANDAN SSR study. This information should be of great interest to utility planners and engineers studying the SSR problem on other series-compensated systems.