Delivering a 132/33 kV substation, 40 km of 33 kV cabling and grid integration for 20 Nordex turbines
Project Snapshot
| Client | Innogy Renewables |
| Location | Scottish Highlands — ~11 miles south of Inverness |
| Project Value | £2.3 million |
| Project Duration | 15 months |
| Market Sector | Renewable Energy — Onshore Wind |
| Services Delivered | Electrical Balance of Plant (EBoP): 132/33 kV substation, HV cabling, switchgear, protection & control, SCADA, earthing, commissioning |
| DNO / Transmission | SSE (DNO); interface to SHETL (132 kV transmission) |
| Installed Capacity | 48.5 MW — 20 × 2.5 MW Nordex N90 turbines |
| Connection Voltage | 132 kV |
| Energy Equivalent | Electricity for ~100,000 households |
| On‑site 33 kV Cabling | ~40 km |
Client & Site Background
Glen Kyllachy Wind Farm is a key renewable energy project in the Scottish Highlands, designed to contribute materially to Scotland’s ambitious renewable and net‑zero goals. With 20 Nordex N90 2.5 MW turbines (48.5 MW total), the site exports clean power via a dedicated 132/33 kV substation, supporting regional decarbonisation and energy security.
The Challenge
- Deliver a complete EBoP package on a remote Highland site, under challenging weather and terrain conditions.
- Integrate the wind farm at 132 kV, ensuring full grid‑code compliance, robust protection/controls and reliable SCADA communications.
- Maintain programme certainty despite COVID‑19 disruptions, safeguarding health & safety while progressing critical‑path activities.
Our Engineering Solution
Powersystems delivered the end‑to‑end EBoP scope, including:
- 132/33 kV substation: transformer, 145 kV SF₆ dead‑tank circuit breaker (with metering/protection CTs), 145 kV Lucy double side‑break disconnector with dual earth switches and Castell interlocking, busbar supports/conductors, surge arresters, and 132 kV inductive VTs.
- Point‑on‑Wave (PoW) switching: Vizimax Synchroteq Plus controller to minimise inrush/flicker and meet P28 requirements during transformer energisation.
- 33 kV network: ~40 km of aluminium single‑core 33 kV cables with longitudinal water‑blocking; trenchless/plough installation where practical; full jointing & termination.
- 33 kV switchgear: 4‑panel Schneider WS board with busbar VT and protection relays (MiCOM P341), including G99 interface protections.
- Protection, control & SCADA: Interface panels, trip & interlock logic, multi‑core controls; fibre‑optic backbone linking turbines, substation and control systems.
- Earthing: Comprehensive earthing for turbines and substation (earth electrodes, bare copper, step/touch design).
- Ancillary systems: Transformer bund pump with oil detection & SCADA monitoring; 50 kVA diesel generator for LV backup; mains‑failure changeover panel; emergency trip PBs; battery charger.
- Building services: Substation LV fit‑out (lighting, small power, heating), fire & intruder alarms, and communications.
Project Process
- Design & Grid Studies — Load flow, short‑circuit, protection coordination, harmonic and grid‑compliance studies.
- Early Works (Oct 2019) — Site establishment, access tracks, substation platform.
- COVID Suspension (Mar 2020) — Controlled pause; safety protocols embedded.
- Restart & Electrical Works (Jul 2020) — Install major electrical components, progress HV cabling.
- 132/33 kV Substation Build — Erection of primary plant, protection/control panels, LV services.
- 33 kV Cabling & Earthing — Trenchless/plough methods adopted where suitable; tests and VLF.
- Switchgear & Controls — Install/commission Schneider WS board, relay settings, SCADA integration.
- Energisation & Commissioning (from Mar 2021) — Staged grid energisation, turbine erection, pre‑ and post‑energisation checks.
- Completion (H2 2021) — Operational commencement and performance monitoring.
Project Facts & Figures
- 48.5 MW total capacity (20 × 2.5 MW Nordex N90)
- 132/33 kV substation integration
- ~40 km of 33 kV cables + fibre network
- 4‑panel Schneider WS 33 kV switchboard
- Vizimax PoW controller for compliant transformer switching
- MiCOM P341 directional OCEF & G99 protections
- 50 kVA LV backup generator and automatic changeover
- Electricity for ~100,000 homes (equivalent)
Technical Specifications
High‑Voltage (132 kV) Systems
- 132/33 kV transformer and ancillary plant
- 145 kV Lucy double side‑break disconnector + 2 motorised earth switches (Castell interlocking)
- 145 kV SF₆ dead‑tank circuit breaker with metering/protection CTs
- Busbar supports & conductors, surge arresters, 132 kV inductive VTs
- Vizimax Synchroteq Plus PoW controller (P28 compliance; reduced flicker/inrush)
33 kV Cables & Substation
- Aluminium single‑core 33 kV cables with longitudinal water‑blocking
- Ploughed/trenchless installation where suitable; VLF testing and continuity checks
- 4‑panel Schneider WS switchgear with busbar VT
- MiCOM P341 protection (directional OCEF) + G99 grid protection scheme
SCADA, Control & LV
- Fibre‑optic SCADA network linking turbines, substation and control room
- Interface/control panels, trip circuits, local/remote switching
- LV services: lighting, small power, heating; fire & intruder alarms
- Transformer bund pump with oil detection & SCADA monitoring
- 50 kVA standby generator + mains‑failure changeover panel; battery charger
Earthing
- Substation and turbine earthing systems (electrodes, bare copper, specialist design for step/touch)
Partnerships
- Innogy Renewables — Client & project owner
- RJ McLeod — Principal civil engineering contractor
- SSE / SHETL — DNO/transmission interface (132 kV)
- Powersystems — EBoP design, installation, testing, commissioning
Key Risks & Mitigations
- Remote Highland conditions & severe weather – Mitigation: Bespoke logistics planning; weather‑resilient work packs; cold‑weather procedures.
- COVID‑19 programme disruption – Mitigation: Health protocols, resequenced activities, parallel off‑site build of panels and controls.
- 132 kV primary plant switching & grid compliance – Mitigation: PoW energisation strategy, robust ITPs, witnessed tests and staged commissioning.
- Earthing performance on varied geology – Mitigation: Detailed design/modelling; enhanced electrodes; verification testing.
Environmental Considerations
- Trenchless/plough cable installation to minimise excavation footprint.
- Oil‑management & spill containment via bund‑pump monitoring and alarms.
- SCADA‑enabled performance optimisation to reduce losses.
- Long‑term contribution to renewable generation and reduced carbon intensity.
Economic & Community Benefits
- Significant construction employment and local‑supply‑chain engagement.
- Long‑term O&M activity supporting local services.
- Reliable, subsidy‑free‑ready renewable generation strengthening Scotland’s energy mix.
Future Prospects
With robust protection, SCADA visibility and compliant PoW switching in place, Glen Kyllachy is engineered for stable long‑term operation, smooth grid interaction and straightforward adaptation to future regulatory or capacity changes.
Related Projects
- Onshore Wind — EBoP & Grid Connection (33–132 kV)
- BESS — Grid Integration, Control & Protection
- Solar PV — HV Substations & Private Networks
Planning a new wind farm or 132/33 kV substation project?
Speak to Powersystems about turnkey EBoP, grid compliance and high‑voltage delivery for utility‑scale renewables.