摘要：At the present time, there is a worldwide tendency to clustering the electrical power systems at LV and MV levels – creating the micro-grids. In this connection, numerous of technical issues appear in control approaches in general and in particular in emergency and post-emergency control. As micro-grids are meant to operate both in interconnected and islanded modes, the ability to steadily island and backward synchronize with an upper grid provides reduction of the negative impact of failure rate of electrical power system’s elements, as well as power quality parameters influence toward operation regime of the loads. The consequence of previously described features is particular requirements for the following emergency automatics: overload-preventing automatics for overhead lines, cables and transformers; out-of-step automatics and under-frequency load shedding. Low inertia constants of some distributed generation units and low time constants of electromagnetic transients of generating units and ESS, interconnected with a grid by means of power-electronics, provide an ability to realize additional (fast) control signals in overload-preventing automatics, dispatching generating units and ESS with an aim to prevent considered elements tripping.
