Prototype Microgrid Design and Results

Microgrids can be considered as a tool to improve the power distribution system reliability and a platform to integrate renewable energy into the power grid. In the absence of large rotating synchronous generators, often microgrid voltage waveforms are formed by power electronic converters. These converters operate at constant voltage (constant V -f) mode operation when the microgrid is in islanded configuration and operate at constant power (constant P-Q) mode when the microgrid is connected to the main power grid. It is important to understand the performance of converters in terms of managing power balance within the microgrid both when they are connected to the main power grid and at stand-alone. Results of an experiment conducted with a prototype microgrid are presented. The prototype microgrid is purely formed by a three-phase converter bank. It is a three-phase unbalanced AC-DC network with a connected single phase Battery Energy Storage System (BESS), AC load and a DC load. Details of all network elements of the microgrid are included in the paper. By comparing voltage measurements to power flow analysis results, it was concluded that converters could manage the microgrid power balance.