Assessment of the Structural Characteristics of Electrical Transmission Systems Using a Graph Theoretic Measure

Conference: International ETG Congress 2017 - International ETG Congress 2017
11/28/2017 - 11/29/2017 at Bonn, Deutschland

Proceedings: ETG-Fb. 155: International ETG Congress 2017

Pages: 6Language: englishTyp: PDF

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Scheufeld, Oliver; Kalisch, Lukas; Moormann, Andreas; Krahl, Simon; Moser, Albert (Forschungsgemeinschaft für Elektrische Anlagen und Stromwirtschaft (FGH) e.V., Aachen, Germany)

European Transmission System Operators (TSOs) experience significant changes regarding the use of their networks in recent years. Due to the climate policy of the European Union (EU) and the corresponding implementation of strategies to achieve its objectives defined by the member states, the installed capacity of generation units based on renewable energy sources (RES) has made a significant development, particularly in Germany, in recent years. Furthermore, the integration of national energy markets towards one common European market creates an increase of power flows between control areas. These changes have an impact, among others, on operational planning and real-time operation processes given the fact that these processes benefit from experience gained by TSOs in past decades, which is not fully compatible with the new situations arising. Hence, additional tools to support the assessment of the state of the system during both processes can help to mitigate the challenges caused by those situations, which did not appear in the past. The methodology presented in this paper provides the basis for the assessment of the structural characteristics of all branches of a transmission network. Using a graph theoretic measure and considering electrical characteristics such as the impedance as weights, the lines are assessed regarding their relative sensitivity to potential violations of operational limits. The result of the assessment is a ranking of all lines for a defined configuration (i.e. switching state) of the network. This ranking can serve as an input for various applications e.g. for the comparison of different switching states in the operational planning process. Given the fact that the use of the system has a direct impact on the loading of lines and is not considered by methodology presented, the ranking can support but not replace calculations and analyses determining the state of the system. Exemplary analyses are carried out on an IEEE 118-bus test system. The ranking is evaluated by comparing it with the ranking obtained from load-flow calculations for different system use cases. The results obtained show that the methodology provides a valuable input for operators. However, the final proof of the concept has to be provided by testing the methodology on a system of realistic size and with realistic system use cases and switching states.