On the Optimality of Voltage Unbalance Attenuation by Inverters

In this paper, we investigate the control of inverter-based resources (IBRs) for optimal voltage unbalance attenuation (OVUA). This problem is formulated as an optimization program under a tailored dq-frame, which minimizes negative-sequence at point common coupling (PCC) subject to current, active power, synchronization stability, and feasibility constraints. The inherently nonconvex intractable. So, guarantee optimality, rigorous optimality analysis performed by leveraging analytical optimization. divided into two cases: full mitigation VU partial VU. For former case, directly solve original since resultant immediately deducible. latter one, solving becomes very hard. Thus, reformulate equivalent but more tractable form certain conditions, optimum can be derived. It found that trajectory has three stages (O1–O3), depending on critical boundary conditions (C1 C2). We implement with photovoltaic (PV)-storage system developing OVUA controller. proposed approach demonstrated dynamic simulations different compared several existing practices. Finally, discuss extension solution in multi-IBR system.