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TD4 - Emergency Functions - Islanding with several Microgrids and Blackstart

Regarding islanding the effectiveness of a coordinated voltage and frequency control strategy needs to be investigated. At the MV level these studies will exploit the equivalent dynamic models developed in TD2, since the multi-Microgrid will assume a complexity level and dimension that requires such an approach. The provision of primary and secondary reserve needs to be studied in a coordinated way having in mind the control capabilities of MV connected DG and the operational limitations of Microgrids. Load shedding strategies will be included here to assure the survival of the multi-Microgrid. Dynamic simulations will be performed, testing different control strategies, under a pre-defined dynamic simulation environment. Microsource models and their controls, developed in the Microgrids project, will be adopted here. These studies will be developed by ICCS/NTUA with the participation of INESC Porto and ABB. Results from TD3.3 and TC2 will be exploited here.

For black start, the identification of the sequence to be followed that minimizes loss of supplied energy needs to be investigated, considering the characteristics of controllability of the DG units installed in the MV level and having in mind the type of control existing in the different Microgrid cells. These sequences should involve the synchronization of Microgrids at MV level, assuming that a black start in the LV was well succeeded (results from the Microgrids project will be exploited). A two stage approach will be tried, involving the use of an EMTP-RV platform (or equivalent) to analyse initial fast transients that exist during the energization and synchronisation stages and a dynamic simulation platform to take care of the next steps. Protection relay settings of the DG, microsources and load shedding will be taken into account. Identification of new relay settings will be tried, exploiting a concept of adaptive relay for which settings can be centrally modified for specific scenarios. ICCS/NTUA and INESC Porto will participate in these studies and developments.