Development of Testing Method for Smart Substations with Prosumers

The paper presents a concept of design and realization of a new testing method for distribution substations which form a microgrid with prosumers. The distribution substation acts as a service provider for distributed resource units in a microgrid and can be used for bidirectional energy exchange between prosumers, such as electric vehicles, battery pack energy storage devices and utility networks. Use of distribution substations equipped with energy storing and bidirectional energy exchange capability enable peak load shaving and demand response, which will reduce the need for new investments into building new power sources or electric power grids to meet peak demand. While the state of the art in the field analyses mainly different theoretical microgrid topologies and integration of unidirectional distributed energy resources, focus in this paper is on practical issues regarding bidirectional energy exchange, which can provide solutions to microgrid manufacturing enterprises. Protection and control functions of the low voltage part of the distribution substation must be tested prior to exploitation. The new testing method for substations includes both computer simulations and practical verifications for automated energy exchange. Simulation results can be used to define and optimize parameters for protection and control functions before constructing a real microgrid. Functions of an experimental microgrid application were simulated with MATLAB, which showed that several prosumers can be served simultaneously and effectively utilized for peak shaving of utility network loads. The results of the simulations were used to develop sample control algorithms and program modules for the substation controller of the experimental microgrid prototype.