AMETEK's largest AC grid simulator

NREL’s advanced energy group plans to use the high power inverter for characterisation and testing of electrical grid systems. Specifically, the systems are being used at NREL’s 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 powerful 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 270kW of power. Eight control chassis allow NREL engineers to remotely configure the system as a single 2MW, two 1MW systems, four 540kW units, two 810kW unit and two 270kW unit or eight separate 270kW 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.

The systems have been customised to allow NREL engineers to control it 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.

HIL 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 analogue 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.