This paper proposes a dynamic intelligent method for voltage violation management in high-renewable-penetration distribution networks. The method employs a dual-agent architecture: DERMS_Agent coordinates task scheduling, data management, and computational resource allocation, while Solution_Agent performs three-phase unbalanced power flow calculation and MIQP-based voltage violation joint optimization. Four key technical contributions are presented. (i) An asymmetric nodal admittance matrix is developed to incorporate transformer tap-phase-shift and capacitor branches within a unified formulation. (ii) Five categories of analytical sensitivities are systematically derived, covering transformer tap, phase shift, and capacitor compensation effects for both voltage regulation and harmonic suppression. (iii) A three-parameter MIQP joint optimization model is constructed with voltage deviation minimization as the objective and three-phase unbalance and resonance avoidance as constraints. (iv) A two-stage hybrid solution strategy combining Ipopt continuous relaxation with Gurobi neighborhood enumeration is designed to achieve real-time solvability. Validation on a real 10 kV feeder with 91 transformer areas over 768 time sections (8 days) demonstrates a 95.6% voltage violation resolution rate within the first three polling cycles and an average single-section solution time of 0.83 s, satisfying the real-time requirements of 15 min operational control cycles.
Hua Zhang, C. Long, Xueneng Su et al.· Processes· 0 citations
Parallel-inverter microgrids are prone to PCC voltage distortion during islanded operation with nonlinear and unbalanced loads. Virtual-impedance methods can reshape inverter output impedance, but they also add control complexity and may introduce extra voltage drops. This paper proposes a droop-based PI-QPR control strategy to improve PCC voltage quality in islanded parallel-inverter microgrids. The droop scheme generates the fundamental voltage and frequency references, and the PI-QPR voltage outer loop regulates the fundamental, negative-sequence, and dominant low-order harmonic voltage components in the dq synchronous reference frame. The PI regulator is used for the fundamental component, while QPR branches at 2ω0 and 6ω0 compensate the negative-sequence component and the dominant fifth- and seventh-order harmonics. No additional virtual-impedance loop is introduced. Two-inverter hardware-in-the-loop (HIL) tests were conducted under nonlinear and unbalanced load conditions. Compared with the traditional voltage controller, the proposed controller reduces the measured three-phase PCC-voltage THD from 5.79–6.02% to 2.41–2.79%, confirming improved PCC voltage quality in the tested islanded condition.
Jinhao Shen, Hua Zhang, Xueneng Su et al.· Applied Sciences· 0 citations
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