AMETEK Programmable Power announced that the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has placed an order for its second regenerative AC/DC high-power source.
When installed in parallel with the previous California Instruments RS Series units purchased in 2013, the new system will have the capability to supply up to 2 MVA, making it not only the largest system built by AMETEK Programmable Power, but the largest known AC grid simulator in the world with the bandwidth and modularity of the RS system.
NREL’s advanced energy group plans to use the high-power inverter for characterization and testing of electrical grid systems. Specifically, the systems are being used at NREL’s Energy Systems Integration Facility (ESIF), the nation’s first facility that can conduct integrated megawatt-scale research and development of the components and strategies needed to safely move clean energy technologies onto the electrical grid.
The California Instruments RS Series of high-power AC/DC power systems provide controlled AC and DC outputs for a wide variety of research, ATE and test applications. The RS Series provides a combination of high power density and simple installation without the need for elaborate cooling schemes.
Each of the two systems consists of four RS270 units, each capable of generating 270 kVA of power. Eight control chassis allow NREL engineers to remotely configure the system as a single 2-MVA unit, two 1-MVA systems, four 540-kVA units, two 810-kVA units and two 270-kVA units, or eight separate 270-kVA units. This capability will give NREL the flexibility it needs to simulate power grids to better understand how different renewable energy technologies interact with each other.
In addition, the systems have been customized to allow NREL engineers to control them in real time via external drive signals. These modifications bypass the system controller and allow the external signals to directly control the high-power source. This eliminates processing delays and allows the system to be used with NREL’s hardware-in-the-loop (HIL) simulators.
Hardware-in-the-loop simulation is not a new concept, but adding megawatt-scale power takes research to another level. In a power hardware-in-the-loop (PHIL) experiment, portions of a power system being studied are modeled in software, while other portions exist as actual hardware.
The hardware components interact with the software model via an interface, which includes a power amplifier capable of converting digital or low-level analog representations of modeled quantities into electrical power waveforms. In this way, the power amplifier can be controlled to apply the same electrical waveform to the hardware components that those components would have seen had they been connected to a real-world power system instead of a model. NREL will use the AMETEK grid simulator(s) as the power amplifiers for MW-scale PHIL experiments.
Other key features of the RS Series include
- Power regeneration. The RS Series can return up to 85% of the power generated by an inverter, meaning the ESIF consumes 85% less energy during testing. This approach eliminates the need for traditional AC source and load combinations. The result is a simplified system configuration while offering up to 85% less heat dissipation. That not only reduces energy costs but also drastically reduces air- conditioning requirements.
- Sophisticated signal generation and measurement. The RS Series uses a sophisticated digital signal processor-based arbitrary waveform generator and power analyzer. This integrated, multi-instrument approach effectively eliminates the need for additional equipment to create a complete AC power test system.
