Research laboratory for grid integration of distributed renewable energy resources - design and realization -

The growing amount of electric energy generated from distributed energy resources (DER), mainly of renewables, requires their appropriate integration into the electrical grid. These distributed renewable power sources are mainly feeding-in the power via converters and can be controlled well. Investigation of their grid integration means investigating their control and hardware concept in the dedicated grid environment. Measurements at downscaled systems in a laboratory environment are a time- and cost-efficient way to investigate this. The properties of the electrical grid, voltage amplitude, frequency and phase as well as the grid impedance can vary substantially by time, the grid impedance moreover is frequency dependent. These properties have to be emulated for the measurements of the grid integration. A dedicated research laboratory test-bench has been developed. The laboratory comprises special developed systems for grid voltage emulation, sag generation, grid impedance emulation, grid voltage correction and grid impedance analysis. Here, the design and realization of these systems in the laboratory test-bench for investigations on grid integration of distributed renewable energy resources are presented. Representative measurements for each system prove their functionality.