Optimal Operation of Active Distribution Network Involving the Unbalance and Harmonic Compensation of Converter The massive accessing of unbalance and nonlinear loads to a power distribution network may cause serious problems on power quality and result in additional power loss and safety risks. Distributed generation (DG) with a converter interface has a flexible adjusting ability and can provide certain unbalance and harmonic compensations to power distribution networks. In this study, an optimal operation method of an active distribution network (ADN) involving the unbalance and harmonic compensation of a converter was proposed. First, the power regulating characteristics of DG were analyzed. Second, an optimization model was constructed to minimize ADN power loss, sum of harmonic voltage squares, and total unbalance of the negative sequence voltage, and multiple constraints, such as converters and network, were considered in the model. Third, the optimization model was transformed into a semidefinite programming model based on the characteristics of the nonconvex and nonlinear original model, thus assuring global convergence and decreasing difficulties in problem solving. Finally, the validity of the proposed algorithm was verified by using IEEE 33node and 123node test systems.

A Control Strategy for Voltage Unbalance Mitigation in an Islanded Microgrid Considering Demand Side Management Capability Inverterbased distributed generators (DGs) have been customarily used for voltage unbalance (VU) mitigation in microgrids. The sole dependency on DGs for VU mitigation may not be justified, particularly in islanded microgrids. Demand side management (DSM) can be a potential candidate for VU mitigation in microgrids. Therefore, this paper presents a new VU mitigation scheme for an islanded microgrid by coordinating photovoltaic (PV) gridtied inverters, and thermostatically controlled loads (TCLs). A negative sequence compensation loop working in parallel with a positive sequence compensation loop is designed for PV inverters for VU mitigation. Also, a voltage dependent model of TCLs, unlike the conventional one, along with the control strategy for VU mitigation is presented. The proposed control of TCLs not only minimizes VU, and hence increases the dynamic reactive power reserve of the inverter based DGs, but also effectively maintains the customersu0027 thermal comfort. The proposed VU mitigation scheme is studied with comprehensive simulations in PSCADEMTDC, and is verified using a realtime digital simulator, OPALRT. Simulations and realtime results of the proposed scheme demonstrated the regulation of voltage unbalance factor (VUF) within the permissible range defined by IEC and CIGRE Working Group 36.07.