ECN publication
CRISP - Distributed Generation as a means to increase system robustness
Fontela, Miguel; Andrieu, C.; Bacha, S.; Hadsjsaid, N.; Besanger, Y.
Published by: Publication date:
ECN Energy in the Built Environment 14-9-2007
ECN report number: Document type:
ECN-O--07-010 Other
Number of pages: Full text:
168 Download PDF  

The present document is in some parts additional and complementary information to D.1.1. The need to share a common vocabulary with similar terms having different meanings leads us to give and define the usual technical words used in the power electric system and computer science (the reader will find a glossary of some terms). The direction of the works in WP 1.3 and also in other CRISP tasks leads to the definition of more concepts about the transmission and distribution system operation: ways to regulate frequency and voltage (ancillary services), benefits of distributed generation at the distribution level, current indices to qualify the system operation. These questions are defined and detailed to fix a baseline in order to define the robustness criteria which limit the DG insertion. These robustness criteria and indices are proposed and they evaluate the system when faced to major contingencies. They take into account the static limits of the system, the amount of DG insertion, possible load shedding and the dynamic stability. Thus, the indices give an idea about the state of the system and warn the operator to take remedial in a preventive step in order to avoid catastrophic consequences. One main goal of the work involved in WP 1.3 is to demonstrate the improvement of the system robustness when faced to major events, these major events are defined and some specific events caused by DG and susceptible to provoke a catastrophic event are specially detailed. This increase of the robustness is not always enabled by the DG because its dynamic characteristics. Therefore, different scenarios of DG performance are analysed in order to define an appropriate amount of insertion and the limiting factors. These scenarios of DG performance analyse the influence of different parameters such as: DG disconnection protection, intermittence, participation to the frequency control and to the voltage control. The system robustness would be enhanced if DG stands the system in critcal situations, one possibility to increase the robustness it is the islanding operation at transmission and/ or distribution. The ability of islanding is commented and the new required distributed intelligence is detailed. On other side, one critical point to create islands is the protection system which is sited. Finally, special attention is paid to communication and control aspects related to DG integration. A new architecture based on an IP network is proposed to integrate all the services of utilities in a unique network. Then other concepts such as observability, dispatchability, control and coordination are briefly commented e.g: it is necessary an increase of the observability of distribution networks which it is not today the common practice.

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