Online Split-Phase Identification of Asymmetric Parameters Between Distribution Lines and Ground for Unbalanced Voltage Compensation Based on Power Electronics

Most of the phase-to-ground parameters induced between distribution lines and ground are asymmetric, which can result in the generation of unbalanced voltage, shifting the neutral point voltage. For compensated distribution networks, the existence of an arc suppression coil can increase the influence of asymmetric parameters and exacerbate the deviation of neutral point voltage. Maintaining the balance of three-phase voltage is a prerequisite not only for the stable operation of the distribution networks but also for improving the reliability of single-phase ground fault detection. This article proposes a novel online split-phase identification of asymmetric parameters between distribution lines and ground for unbalanced voltage compensation based on power electronics. First, an adaptive active current-type compensation method based on power electronics is proposed; it can adapt to compensate for three-phase unbalanced voltage with different neutral point grounding styles. Second, particle swarm optimization is used to realize the online split-phase identification of the phase-to-ground parameters of the distribution power lines. The identified parameters are used to calculate the reference value of the compensation current and the asymmetry of each phase-to-ground parameter. Finally, the feasibility and effectiveness of the proposed method are verified by simulation and experiment.