A Power Hardware-In-The-Loop Simulation Facility for Testing Grid-Connected Storage Systems

A power hardware-in-the-loop (PHIL) facility for grid-linked energy storage is evaluated in this research in terms of communication latency, and power system model performance. The PHIL consists of a 240 kVA 180 kWh Siemens SieStorage battery energy storage system (BESS), which via a dSPACE real-time platform is interfaced using TCP/UDP Ethernet to a real-time digital simulator (RTDS). The communication latency has been monitored at the dSPACE and RTDS side, and for the ramp signal used in the loop-back test the average latency was only 2.32 ms, and 99.8% of the transitions analysed had a 2 or 3 ms latency. The RTDS was then demonstrated to command the BESS, and the overall time delay in this test was 646 ms, of which, over 50% is due to the communication between the dSPACE and SieStorage system. The Ethernet comms latency is several orders of magnitude smaller than the BESS response time, and so this enables the PHIL to be used in future studies requiring a fast system response, such as frequency regulation, with a high accuracy. The RTDS was then used to command the operation of the BESS, and the measured real-time data from the BESS was used to impose changes on a basic power system model running in real-time on the RTDS.