ETF Update: PV Emulator and Fault Emulator

ETF Update:  PV Emulator and Fault Emulator

Work in ACEP’s Energy Technology Facility (ETF) recently has been focused on bringing a PV emulator and fault emulator online.  Once complete both of these new pieces of technology will be very useful additions to the lab.

The fault emulator will allow researchers to see how equipment responds to fault conditions (short circuits) between phases (phase to phase faults) and between phases and ground (phase to ground faults). Such faults could be triggered, for example, by a tree fall, or a car accident involving a distribution line. The fault emulator is designed to generate faults of up to 10 kA at 480 VAC for a quarter cycle, or lesser faults for longer periods of time. Researchers will be building a control loop to time the fault to an exact moment within the voltage sinusoidal wave.

Understanding fault behavior in weak grids, particularly grids heavily relying on power electronics-based equipment (PV, modern wind turbines, energy storage systems) is important for protecting equipment and the grid sufficiently based on the fault behavior of grid components. 

A PV emulator will mimic up to 100 kW of modern PV panels by using a special DC power source capable of providing voltages up to 1000 VDC and changing power output very quickly, just like a PV array when a cloud passes over. The DC power source will be setup such that researchers will be able to flexibly connect various types and sizes of PV string inverters. Researchers are currently specifying a baseline model inverter (>30 kW) to act as the standard inverter.

Installation of the fault and PV emulators will add to the Power Systems Integration Lab's existing research, development, and demonstration capabilities offering   a full range of R&D environments to support the Alaska Center for Microgrids Technologies Commercialization project, funded by the US Economic Development Administration and ACEP in equal parts. Both emulators are expected to be operational by the end of Q1 2016.

Photo: Image of 100 kW power source for PV emulator in ETF.  Photo credit M. Frey, ACEP/UAF.