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This paper presents an on-line operational optimization approach to determine the optimal reactive power/volt-ampere reactive (VAr) set points for open unified power quality conditioner (UPQC-O) under varying load demand of a distribution network. The UPQC-O consists of series and shunt inverters. The modeling of UPQC-O is done to provide VAr support to a network, to mitigate supply voltage sag to the downstream buses, and to eliminate harmonics present in the line current. A non-linear optimization problem is formulated to determine the optimal VAr set points for the inverters of UPQC-O in each loading condition. The objective function is the minimization of energy loss. The limits on bus voltage magnitude, line current flow, and maximum VAr support capacities of inverters are considered to be the operational constraints. The optimization is performed with the data of hourly varying load demand for different seasons in a year. The optimization problem is solved using CONOPT solver of general algebraic modeling system. The cost-benefit analysis and the infrastructure required for the real time implementation of the proposed methodology are also provided. The simulation results show the effectiveness of the proposed approach in energy loss reduction. [ABSTRACT FROM AUTHOR]

The study presents the modelling and allocation strategy for open unified power quality conditioner (UPQC‐O) integrated photovoltaic (PV) generation system in radial distribution networks to improve the energy efficiency and PQ. An UPQC is a custom power device, which consists of series and shunt inverters. In UPQC‐O, these inverters are placed in different locations in a network. There is a communication channel to share the information among these inverters to select the respective set point. Two models proposed are: (i) UPQC‐O with battery and PV array (UPQC‐O‐WB) and (ii) UPQC‐O with only PV array (UPQC‐O‐WOB). In UPQC‐O‐WB, the energy generated by PV array is stored during its operation hour to utilise it during peak hour. However, in UPQC‐O‐WOB, the energy generated by PV array is directly injected to the network. The proposed models are incorporated in the forward–backward sweep load flow to determine the operational parameters such as bus voltage. An optimisation problem is formulated to determine the optimal placement of UPQC‐O with PV array in distribution networks. The objective function includes the investment and operational costs of inverters, battery and PV array, and the cost of energy loss. The particle swarm optimisation is used as the solution strategy. [ABSTRACT FROM AUTHOR]