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

Abstract

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.

Advanced building energy management based on a two-stage receding horizon optimization

“…A microgrid laboratory equipped with wind turbine and photovoltaic panels, passive and active loads and grid voltage, sag and impedance emulators based on power converters has been presented in [45,46]. The environment in [47] is organized in two microgrids that integrate distributed generators, storage systems and loads and controlled by a hierarchical control structure.…”

Simplified distribution grid model for power quality studies in the presence of photovoltaic generators

“…Additionally, in integration studies, the TEC is chosen randomly according to the needs of the investigation or on an empirical basis (taken from survey data [34]) giving useful but general results which may differ from real case scenarios. Furthermore, despite the fact that online methods for defining TEC do exist [35,36], they can only utilise the capabilities of an already installed distributed generator (as the aforementioned methods are incorporated into the inverter control circuit) and cannot contribute in distribution grid expansion and planning. This contribution moves one step forward using a validated/accurate TEC for voltage quality studies and for evaluating voltage regulation schemes based on the actual distribution grid dynamics at the PCC.…”