Coordinated control of active distribution networks to help a transmission system in emergency situation

This paper addresses the relevance of using reactive power from Medium Voltage (MV) networks to support the voltages of a High Voltage (HV) rural network in real-time. The selection and analysis of different optimal coordination strategies between the HV and several MV grids is investigated. The algorithms will control the reactive powers that can flow between HV/MV networks after a request from the Transmission Network Operator in case of an emergency situation such as a line outage. From a case study, the relevance of the coordination is enlightened and recommendations are given on how to tune and to combine the optimal algorithms with the advanced Volt Var Controllers of the distribution grids