Power Hardware-in-the-Loop Verification of a Cold Load Pickup Scenario for a Bottom-up Black Start of an Inverter-dominated Microgrid

Black start capability is one of the challenges in the future grid, to be dominated by distributed power electronic converter systems. A bottom-up multi-master black start scenario based on droop-controlled grid-forming inverters was earlier introduced as a response to this challenge. With reduced reliance on the availability of smart loads, this paper adapts this scenario so that a minimum change in the current configuration of the low voltage residential load sector is required. Moreover, with a focus on the cold load pick-up response, the power-sharing among two grid-forming inverters in the presence of high inrush currents is investigated using Power Hardware-in-the-Loop tests and detailed load models. The results confirm the formation of a laboratory-scale islanded Microgrid through grid-forming inverters where smart meters coordinate an autonomous dynamic partial loading only based on local measurements.