Protection study for SST-integrated LVDC networks with multiple feeders

To enhance the adaptability of low voltage (LV) networks and release additional network capacity towards enabling the wider uptake of low carbon technologies, SP Energy Networks’ (SPEN) LV Engine project aims to design and trial the first UK solid state transformer (SST) for deployment within secondary substations (11/0.4kV). This project aims to form the first LV direct current (LVDC) trial at a utility scale in the UK. The SST and the introduction of low voltage DC (LVDC) supplies will present fundamental changes in the operation of existing secondary substations and will introduce new LV fault profiles for the associated LVDC distribution networks. This paper presents the results of joint work between the University of Strathclyde, SPEN and WSP with the primary objectives of identifying suitable DC protection and fault discrimination approaches for LVDC networks with multiple feeders and DC loads. This work intends to reflect the challenges and potential solutions for LVDC protection.