CERTS Microgrid Laboratory Test Bed

Abstract

SUMMARYThe objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2) an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources.These techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults.The results from these tests are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field demonstrations involving microgrids that involve one or more of the CERTS Microgrid concepts. Future planned microgrid work involves unattended continuous operation of the microgrid for 30 to 60 days to determine how utility faults impact the operation of the microgrid and to gage the power quality and reliability improvements offered by microgrids.

Renewable energy emulation concepts for microgrids

“…Solutions) [5] or facilities developed by other research centers are defining the specifications of the future microgrid concept [6]. In a laboratory scale, other setups are being built, as for example the IREC microgrid (Catalonia Institute for Energy Research) [7] or the platform proposed by the Energy Systems Research Laboratory, Florida International University [8].…”

Research on the relay protection system of micro-grid

“…5. Figure 5 The protection operation time diagram of distributed protection scheme (2) When a fault occurs within the protected area, the overcurrent protection relay will serve as the main protection and detect the fault in around 200 ms, and isolate the fault. If the fault does not disappear after 500 ms, the backup overcurrent protection, progressively in action, isolates the fault.…”

“…In recent years, the distributed generation (DG) and the Micro-grid (MG) system, represented by photovoltaic generation and wind power generation, have received more and more attention from researchers [1,2]. Since different countries focus on different aspects of MG, there is no universal definition to the concept of MG all over the world.…”

A Review of Power Electronics Based Microgrids

“…For example, in the CERTS microgrid, the plug-and-play feature requires that all DG units have a unified dynamic performance regardless of prime energy source type [27]. This implies that an energy storage module with a bidirectional converter must be included within each DG unit.…”