Mobile and modular Substations for the provision of more sustainable and efficient Grid Connection of renewable Generation

This paper will propose two innovative design and delivery systems that aim to reduce this burden through efficiency and standardisation, with the added benefit of being more environmentally sustainable.

The first system is a mobile substation; with the TO proud to have purchased of one of the first transmission voltage, single trailer, full mobile substations in northern Europe. The TO is indicatively planning to use this for transformer replacement projects, allowing for in-situ replacements to occur with reduced outages to the connected customers. The challenges associated with the design phase are detailed, such as specification of the hybrid switchgear and non-standard specification of the power transformer. Furthermore, the detailed planning for site connection are explored, including specification of the trailer for transport to site and onward movements across the network, as well as vector group compatibility, provision of earthing, and split of commissioning activities across factory and site.

The second system is a modular substation, consisting of gas insulated switchgear (GIS) & control modules, which the TO has made significant efforts to standardise and introduce to the business for the majority of future new-build single circuit radially connected renewable generation connections. Due to the compactness afforded by the modular design and the prefabricated nature both the substation size and the duration of site construction works could be halved. The engineering department has led efforts to collaborate closely with a breath of departments; including procurement, design and specification authority, operations, project management and regulation. This collaborative approach has allowed for an efficient and accelerated rollout of a highly complex initiative for the maximum benefit of renewable customers. The specification of the module and equipment within, and additional interfaces to substation construction contractors, as well as construction safety risks are detailed.

Furthermore, the benefits of standardisation are explored, namely, economies of scale through reduced variation in future design, procurement and manufacturing work and consistent experience for operations staff, which improves performance and reduces risks.

Both innovative design and delivery systems better utilise resource, both factory and construction site, which is a more sustainable approach and will only become more critical as the global push for NetZero tests the limits of the skilled resource pool.

The findings in this paper will seek to advance the electrical utility industry’s understanding and adoption of both mobile and modular substations, to provide more efficient and sustainable substation design and delivery, for the benefit of the wider energy industry and global NetZero efforts.