Integrated Local and Coordinated Overvoltage Control to Increase Energy Feed-In and Expand DER Participation in Low-Voltage Networks

Abstract

Large amounts of active power injection by inverter-interfaced distributed energy resources (DER) is a common cause of overvoltage in low-voltage networks. Hence, local active and reactive power control (i.e., Volt/Watt and Volt/VAR, respectively) are adopted to limit voltage rise, leading to active power curtailment. This paper proposes an automatic control strategy to steer non-dispatchable (nd-DER) and dispatchable (d-DER) inverters in low-voltage networks, mitigating overvoltage through integrated local and coordinated Volt/Watt and Volt/VAR functionalities. Moreover, active power curtailment is avoided whenever possible. The method does not require <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</i> ) the implementation of optimization algorithms or <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ii</i> ) knowledge about line impedance parameters or the location of DERs. The control approach exploits the power flow dispatchability of low-voltage networks comprising one point-of-common coupling with the distribution grid, allowing DERs close to the distribution transformer to also contribute to voltage regulation by only using a low-bandwidth communication link. Simulation results show the flexibilities of the proposed approach and demonstrate that active power injection can be increased by up to 25% for the considered scenario in comparison to conventional local Volt/Watt or Volt/VAR schemes. Experimental results based on a laboratory prototype with three inverter-interfaced DERs certify the applicability of the approach to real-life implementations.