To facilitate the connection of Distributed Generation (DG) from renewable sources at the distribution level, the network needs to be capable of withstanding the consequential increase in fault level.

Strategically placed Superconducting Fault Current Limiters (SFCLs) could provide distribution networks with improved capability by limiting the fault current to within the rating of existing switchgear. The installation of SFCLs may allow for the accelerated connection of both renewable and non renewable generation whilst reducing the need for major network reinforcement which is often required to cope with the increased fault level, typically before new DG can be connected.

Currently, a significant proportion of primary and supply point substations on Northern Powergrid's GB network have been identified as having a maximum switchgear duty greater than 95% of the make / break duty rating and this would be typical for GB network as a whole. The connection of additional DG to these sites may increase the fault level beyond the switchgear rating.

Objectives

This project trials a specific piece of new equipment that has a direct impact on the operation and management of the distribution system.

The first phase is to identify suitable locations for the installation and undertake a feasibility and systems readiness study to analyse the network, outlining the optimum application and specification, and confirm the business and carbon cases.

The second phase is to design, build, install and commission a three-phase 33kV superconducting fault current limiter on the Northern Powergrid distribution network. It is proposed, subject to site surveys and agreement with partner organisations, that the unit is installed at a 275 / 33kV substation in South Yorkshire to limit the fault current to within the rating of the 33kV switchgear. This is currently managed through an operational management switching procedure which in some circumstances may increase the risk of loss of supplies to customers.