SG Power Distribution designs high-voltage electrical infrastructure up to 400 kV — connecting renewable generation, data centres, EV charging and development sites to the UK distribution and transmission network. A full turnkey service, from feasibility to energisation.
From the first feasibility sketch through to energisation, every electrical and civil package is produced and checked under one roof.
132 kV primary and secondary distribution design — cable routes, substation layouts and electrical schematics across all voltages, fully compliant with DNO and IDNO standards.
Full distribution compliance studies — G99, G5/5, P28, P29, arc flash, load flow and fault level, and protection coordination.
Earthing and lightning protection calculations, fully compliant with DNO standards, supported by on-site soil resistivity testing.
Substation construction details, structural and busbar force calculations, foundations, compounds, access roads and drainage — coordinated with the electrical design.
Independent technical assurance and design approval for electrical packages, with guidance through every stage of delivery.
Specialist cable route design up to 400 kV — 3D pulling and tunnel-pulling calculations, cable rating, crossings and full thermal (FEM) analysis using advanced software.
400 kV design services — NESO and private network and single-provider reinforcement connections, including full NESO grid-compliance studies.
Connection planning and applications — G99 and load applications, initial studies, network limits, and planning drawings and requirements.
Private HV network solutions — PSC, SCADA and power quality monitoring to IEC and BS standards, integrating private solar sites and interfacing them with the adopted DNO network.
Solar, wind, battery storage and CHP connections.
Resilient, high-load HV supply design.
Developers, landowners and contractors.
Sites, construction and mixed-use.
Charging hubs and supporting infrastructure.
Projects delivered — from hyperscale data centre connections and multi-site renewable grid connections to 132 kV cable routes through a live city centre, plus power system studies, residential and civil schemes.
A 132 kV connection for a hyperscale data centre — a 7 km route delivering 90 MVA through two 132/11 kV transformers (45 MVA per winding) for enhanced security of supply. We designed the 11 kV tails and a bespoke, first-of-its-kind adopted solution: 2500 A / 35 kA rackable 11 kV switchgear with a metered interface to the private network, a portal-frame GIS building and control room, and full protection & control — delivered end-to-end to UK Power Networks standards and adopted by an IDNO.
An 80 MW solar connection spanning three independent generation sites. We designed the grid supply point adopted by Northern Powergrid and the IDNO interface — a 90 MVA 132/33 kV transformer, earthing transformer and dedicated 33 kV metered board — with cabling, SCADA and fibre linking substations up to 8 km away. Full G99, harmonics and distribution-code compliance was approved by the DNO, delivered as a complete turnkey package including all civil works: access roads, drainage, transformer plinths and containerised IDNO buildings.
A 132 kV underground cable connection through congested central Cardiff — a 1.7 km route (1000 mm² Al) carrying 190 MVA from Cardiff East to Central, plus an extended circuit to Cardiff West (1600 mm² Al, up to 200 MVA winter). The scope covered route feasibility and jointing strategy, dynamic cable-rating and cross-bonding assessments, thermal impact on adjacent cables, and pulling calculations to minimise joints — including substation entry through an existing tunnel with bespoke cleat and short-circuit force design. Route-wide hazards were mitigated and the project delivered ahead of programme.
The full civil design package for a 30 MVA data centre substation. We designed the transformer bunds and oil containment (interceptors and fire zones), a Kingspan portal-frame 11 kV switch house to SSEN DNO standards, and the complete compound — steelwork fabrication and baseplate detailing, structural and short-circuit force calculations, foundation rebar scheduling, retaining walls, access roads, drainage, high-security fencing and cut-and-fill. Delivered end-to-end and adopted by an IDNO.
A full grid-compliance study package for the Burtree project, delivered in DIgSILENT PowerFactory to Northern Powergrid and ENA standards. The scope covered G99 and G5/5 (harmonic distortion assessed to the 100th order, with mitigations), P28, load flow and short-circuit studies, reactive and voltage capability, LFSM/FSM inverter and power-park-module compliance, and full protection coordination — including grid harmonic loci across operational and outage scenarios. A challenging G5/5 case was resolved by interrogating and correcting the source parameters.
Master development design and consultancy for a major mixed-use scheme at Wood Wharf, Canary Wharf — an ~53 MVA supply at 11 kV drawing on six boards across three independent sources (Deptford, Simpsons and the Blackwall Way rings) for a high level of supply security. We led the HV ducting and diverse-route strategy, coordinated around 20 primary boards and 28 IDNO-adopted secondary substations (basement and above-ground), and set the phasing strategy to deliver capacity efficiently without disrupting the construction programme or double-handling infrastructure.
An 11 kV bulk-metered DNO connection for a rapid EV charging hub. We designed the private HV infrastructure — 11 kV transformer and ACB — with LV and SCADA cabinets, full SCADA control, LV tails and the hub setting-out, including a TT earthing system for every fast charger. Specialist earthing studies limited the site to a cold (sub-EPR) classification, and harmonic compliance was verified within the required limits.
Share the site, the load and the target DNO — we'll come back with a route to energisation.
Email the team Connect on LinkedIn
