Power Production Maximization Schemes for Grid-Connected Converters - Case Study: Local Distribution Network Under Unbalanced Voltages

Abstract

Voltage unbalances are frequent in distribution networks. They can be transient in nature or can last for several minutes. Distributed generation units that are connected to the distribution network with unbalanced voltages could suffer from the excessive currents flow if active and reactive power references are kept the same as those that were used during the balanced voltage conditions. In order to maximize active and reactive power production, taking into account converters' current ratings, both during the severe, short lasting, and the less severe, longer lasting, disturbances, different schemes are proposed. The power production maximization could be beneficial for faults mitigation and for optimal resources utilization. The first paradigm enables active or reactive power production prioritization. The second allows for the power factor to stay the same before and during the voltage sags. Algorithms were tested on the hardware-in-the-loop based setup that emulates local20kV distribution network with 26 substations.