Affinely Adjustable Robust Counterpart Approach for Local Dispatching of the Inverter’s Reactive Power

An electrical distribution system with high penetration levels of photovoltaic (PV) generation is exposed to degradation in power quality due to voltage fluctuation beyond the acceptable levels; this is caused by the rapidly varying generation levels from the PV generators possibly causing reverse power flows. Currently installed regulation equipment like under load-tap changing transformers, step voltage regulators, and switched capacitors are slow; they cannot provide an adequate response to the fast varying generation levels. A proposed solution is the introduction of fast-reacting PV inverters that can consume or supply reactive power to account for the voltage sags and swells on the distribution network, and that also provide the network operators with the opportunity to optimize thermal losses. This paper presents an affinely adjustable robust counterpart (AARC) approach for the optimal local dispatch of reactive power from the PV inverters; it accounts for uncertainty in the photovoltaic generation levels and aims to minimize the maximum absolute voltage magnitude deviation from the nominal voltage level. Numerical results confirmed the effectiveness of the proposed approach in reducing both the maximum absolute voltage magnitude deviation and the system power loss.