DEVELOPMENT AND OPERATION OF ACTIVE DISTRIBUTION NETWORKS

CIGRÉ Working Group C6.11 “Development and operation of Active Distribution Networks” started its activity in August 2006 during the CIGRÉ General Session. The objectives of the Working Group (WG), as defined in the Terms of Reference were: • Provide a shared definition of active distribution networks; • Identify the enabling technologies; • Identify limits/barriers; • Assess the actual status of implementation of active distribution networks worldwide; • Provide recommendations/requirements for the integration of Distributed Energy Resources (and transition towards more active distribution networks). Firstly, the WG started setting the scene (Chapter 1) in the context of a deeply changing concept of “old” (i.e. passive) distribution networks. At the time, no clear idea of what an “active” distribution network represented was in place, and debate among different stakeholders led to differing views. Bearing this in mind, it was decided amongst C6.11 members to submit a questionnaire to all relevant stakeholders (distribution companies, research organisations, manufacturers, and customer groups) in order to review the present status of implementation of active distribution networks and provide a global, shared definition of active distribution networks (Chapter 2). Survey results indicated that there was no single definition of active distribution networks. However, key concepts could be extracted and, from these, and the following shared global definition emerged: “Active distribution networks (ADNs) have systems in place to control a combination of distributed energy resources (DERs), defined as generators, loads and storage. Distribution system operators (DSOs) have the possibility of managing the electricity flows using a flexible network topology. DERs take some degree of responsibility for system support, which will depend on a suitable regulatory environment and connection agreement.” The second action of the WG was to review the actual status of implementation of active distribution networks, using the answers to the questionnaires and through a review of the most relevant projects worldwide demonstrating active distribution network concepts. (Relevant projects were selected based on criteria agreed amongst the working group.) This exercise allowed the following to be identified: (i) key features of active distribution networks; (ii) enabling technologies; and (iii) how the researchers and stakeholders at the forefront are addressing the integration challenges. The results are presented in Chapter 3.The majority of respondants agreed that the proliferation of distributed generation was one of the key triggers for a change in operating philosophy of distribution networks. Moreover, they identified integration of distributed generators into system operations, to the extent that they take some degree of responsibility for the reliability and operation of the network, as a vital step for the success of the concept. These results are highlighted as part of the WG’s recommendations, which are provided in Chapter 4. Also is this chapter, recommendations to different stakeholders (distribution companies, manufacturers, decision makers, regulators, DG developers) are provided. These recommendations cover what actions should be taken, in terms of system operation, system planning, regulatory activities, and in general to foster adoption of technologies in the transition towards more active distribution networks. The added value of this document is that it provides a snapshot of the state-of-the-art of the active distribution network concept, how it is perceived by the industry, and then proceeds to identify the priorities of what should be done to facilitate its deployment by utilities. The document addresses not only skilled, technical people but also decision makers, in developed as well as developing countries, so that each might to benefit from what is being done worldwide on the subject.