Approach to assessing the effective integration of solid-state transformers in LV networks

Solid-state transformers (SSTs) have been recognised as a promising technology that can realise more flexible power and voltage control in distribution networks compared to conventional low-frequency transformers. The flexibility and controllability offered by this technology can be an enabler of DSO functions. Harnessing these additional functionalities of SSTs requires the identification of tailored approaches to understanding the impact of SST integration on LV networks. Therefore, this study presents a methodology that can assist DNOs to assess the potential impact of SSTs and determine whether it is an appropriate alternative to conventional reinforcement. This approach has been demonstrated with an SST model built within PowerFactory applied to a detailed LV network model based on an example real UK LV network and load. The analysis has demonstrated that SSTs in simple schemes can effectively control network voltage and alleviate loading constraints on existing secondary distribution transformers. However, the level of contribution that an SST can offer is clearly dependent on seasonal loading conditions, network location and cable parameters. This work is a component of the LV Engine project being led by SP Energy Network and funded through the UK's Network Innovation Competition.