Decoupled power flow calculation method for low-voltage distribution networks with distributed generation

Given the inherent three-phase four-wire structure and the prevalent three-phase unbalance in low-voltage distribution networks (LVDNs), existing power flow algorithms face challenges such as decoupling difficulties, inadequate consideration of neutral wire effects, and cumbersome iterative formulas. To address these issues, this paper proposes a decoupled power flow calculation method based on matrix order reduction for LVDNs with distributed generation (DG). First, a comprehensive LVDN model incorporating the neutral wire is constructed, encompassing models for lines, transformers, ZIP loads, and distributed PV. Subsequently, a mathematical transformation is applied to the nodal admittance matrix to achieve order reduction, where the neutral wire parameters are reduced to the phase conductors to eliminate the corresponding rows and columns. Furthermore, a phase-sequence transformation is utilized to achieve sequence-component decoupling of the third-order matrix, thereby establishing the decoupled nodal voltage equations. Concurrently, a sequence-component-based forward–backward sweep (FBS) method is designed for power flow solving. Finally, a 22-node LVDN model with distributed PV is built in MATLAB/Simulink for case verification. The results demonstrate that the proposed method can accurately reflect the asymmetric operational characteristics of LVDNs. Compared with the traditional phase-component method, it effectively simplifies the calculation process and significantly enhances computational efficiency while maintaining high accuracy, providing efficient algorithmic support for the precise regulation and optimal operation of LVDNs with DG.