Advanced dynamic control strategies for electrical distribution networks with active stability participation

Abstract

In the last two decades, there has been a global trend away from conventional energy supplybased on fossil fuels and nuclear energy, towards a more sustainable energy supply based onrenewable energies (RE). The governments of an increasing number of countries worldwideare switching to RE and are in various stages of transition. This has meant that the technicaland economic principles relating to the current power supply process structure need to bereconsidered. On the technical side, the supply with volatile RE, e.g. wind and solar power,which is predominantly supplied from decentralised energy sources, can have a significantinfluence on grid stability. On the economic side, the role of a considerable number of gridusers is changing from passive consumers to producers, also known as ‘prosumers’.Conventional power supply principles, which consider mainly classical power suppliers, canlead to a gap in the implementation of non-discriminatory market conditions for all grid users.As a novel concept for future-oriented power supply systems, the Clustering Power SystemApproach (CPSA) has been developed at the Laboratory of Electrical Energy Supply at theSouth Westphalia University of Applied Sciences, Branch Soest under the leadership of Prof.Dr.-Ing. Egon Ortjohann. The CPSA enables the technical control of power systems and takesinto account the economic processes. With the CPSA, the power system is divided into clusterareas, which transfers the interconnected grid structure of the transmission system operator(TSO) level to the distribution system operator (DSO) level, in order to enable an equitablepower supply process in each grid or voltage level. This dissertation therefore makes a specificcontribution to knowledge and is essentially divided into three main parts.The first part of the dissertation contains a state-of-the art analysis of different smart gridconcept and compares these concepts with the CPSA. The CPSA in turn builds also the basisfor the further investigations provided in this dissertation.The second part of the dissertation examines whether the power supply processes and structureof the TSO level can be broken down to the DSO level. These principles need to be consideredfor cluster control operation within the CPSA, which allows independent automation andoperation of each cluster. The current power supply structure and its processes are studiedbased on the European Network of Transmission System Operators for Electricity (ENTSOE) network codes and adapted to a node-orientated approach.The third part of the dissertation is related to the state estimation, which is a key function fordynamic power system operation and control. In order to be operated within the CPSA, the socalled Grid Node-Oriented State Estimation (GNO-SE) is introduced to validate that the gridnode-oriented approach is suitable for power system operation and control based on the CPSA.This research demonstrates that the necessary flexibility, adaptability and efficiency for thedynamic power system operation and control of the power grid can be provided at DSO level