Perturbation- and Observation-Based Power Decoupling Method of Rotary Power Flow Controllers for Distribution Lines

The rotary power-flow controller (RPFC) is capable of regulating line power flow. However, the traditional RPFC power-decoupling method is associated with power coupling issues in high-resistance-ratio lines. To address these issues, this study investigates an RPFC power-decoupling method for high-resistance-ratio lines. First, the power-coupling relationship of RPFC is analyzed based on the power-regulation model after integration with RPFC. Different power flow contour lines are plotted using different line impedance parameters, and the response characteristics of line flow to the two phase-shifting angles are investigated. Second, a dual-input-dual-output perturbation and observation method aiming at RPFC power decoupling is proposed to achieve power decoupling control, which involves perturbing two phase-shifting angles and determining the next regulation direction based on the changes in power before and after the perturbation. Finally, the proposed and traditional methods are compared based on experimental validation tests on the 380V/40kVA RPFC test platform. The experimental results show that the proposed control strategy demonstrates good decoupling effects under different resistance-reactance ratio conditions, thereby verifying the correctness and effectiveness of the established model and control strategy.