Distribution networks increasingly require advanced technologies to enhance supply reliability and strengthen fault-recovery capabilities. Flexible interconnection devices represent a promising solution by enabling looped feeder operation and optimized power flow, but their performance in real-world networks with high harmonic distortion remains a significant technical challenge.
Researchers have now proposed a novel medium-voltage flexible interconnection device featuring a star-connected topology designed specifically to address harmonic-rich operating environments. The device combines a compact power-module structure with a sophisticated three-tier control architecture. The primary control components include a phase-locked loop for synchronization, hierarchical capacitor-voltage regulation to maintain stable DC-link operation, and an inner current-control loop for precise power delivery.
A key innovation is the dedicated harmonic-current compensation strategy, which works within the overall control framework to actively suppress current harmonics—a persistent problem in distribution networks with nonlinear loads and distributed energy resources. This multi-layered approach ensures stable operation even when background harmonics exceed typical utility standards.
To validate the proposed technology, engineers constructed a comprehensive hardware-in-the-loop testing platform that simulates realistic distribution network conditions while allowing real-time measurement of device performance. Testing confirmed that the device successfully facilitates flexible interconnection of distribution feeders while maintaining robust harmonic suppression. The control strategy demonstrated stable operation across various high-harmonic scenarios without requiring component redesign or manual tuning.
These results indicate that the flexible interconnection device could significantly enhance distribution network resilience by enabling faster fault isolation and restoration through looped topology operation. The harmonic compensation capability addresses a fundamental challenge limiting deployment of power electronics in harmonic-polluted networks. Further field trials would help establish optimal deployment locations and integration procedures with existing protection and control systems.
