Industrial Overview of Back-to-Back VSC Power Links in MV Distribution Networks

This paper presents an overview of Back-to-Back-VSC type power links as a promising technology, yet little deployed, to enhance the operational flexibility of MV distribution networks. It provides a technical insight of four cornerstones that Distribution System Operators could consider from a planning perspective: power electronics, backhaul network characteristics, dispatching control strategies and protection requirements. Details on power electronics and protections are given with an industrial approach, differential with information available in academic works and generic reviews. The paper showcases figures of multi-megawatt size converters and uses a real 30kV distribution network model to assess converter capacity selection and protection requirements. Additionally, different control strategies of Back-to-Back VSC power links are introduced showing the influence that backhaul network can have over them. Seen from a dispatching perspective, an overview of different control strategies is presented describing options available for MV grids that account for different digitalization levels. The overview given in this paper allows to have a clear vision of technology readiness, integration requirements and technical limitations of Back-to-Back VSC power links for its deployment in MV distribution networks.

Automated summary

This paper provides an overview of the Back-to-Back-VSC type power links, which are a promising but underutilized technology for enhancing the operational flexibility of medium voltage (MV) distribution networks. It outlines four key aspects that Distribution System Operators should consider in their planning: power electronics, backhaul network characteristics, dispatching control strategies, and protection requirements. The paper offers detailed insights into power electronics and protections, focusing on an industrial approach rather than academic works and generic reviews. The study presents figures of high-capacity converters and uses a real distribution network model to evaluate converter capacity selection and protection requirements. It also introduces various control strategies for Back-to-Back VSC power links, highlighting the impact of the backhaul network. From a dispatching perspective, the paper provides an overview of different control strategies available for MV grids with varying levels of digitalization. Overall, this paper offers a comprehensive understanding of the technology readiness, integration requirements, and technical limitations of Back-to-Back VSC power links for deployment in MV distribution networks.