Iccles

Project Overview

Enabling Grid Stability Services

DACI Utilities Engineering Consultancy supported the Battery Energy Storage System through a detailed earthing design package covering the BESS site, the 400kV compound and harmonic filter interfaces. The project required coordinated design across high-voltage plant, battery infrastructure, civil constraints and above-ground connections.

Engineering Challenges

Critical Obstacles

Transmission-level interfaces, late-stage coordination actions and dense earthing requirements across adjacent high-voltage and BESS compounds.

Interface Risk 400kV Compound Integration

Earthing continuity across the AIS/GIS interface, CSE structures and adjacent plant required detailed coordination.

High Complexity BESS / Filter Interfaces

The BESS compound, 33kV distribution, harmonic filter and capacitor bank introduced multiple plant-specific earthing requirements.

Technical Depth Above-Ground Earthing

Designs covered transformer, surge arrestor, CVT, CT, EMVT, CSE and disconnector/earth switch arrangements.

Construction Constraint Installed Compound Works

A bespoke assessment was undertaken for the high-frequency earthing rods, as the prevailing ground conditions prevented the installation of standard-depth rods.

DACI Solution

DACI iterated the earthing package to support safe construction and operational reliability across the BESS, 400kV compound and harmonic filter plant.

Integrated earthing layouts from overall site down to plant-level details
Above-ground earthing drawings for 400/33kV transformer, surge arrestors, CVTs, CTs, EMVTs and CSEs
Harmonic filter compound, harmonic filter and capacitor bank earthing drawings
Installation support on bonding lead size, link box earth connection, cleating and lug details
Constructability focus around 400kV compound blinding and earth rod/tape interfaces

Outcome

A coordinated earthing showcase that demonstrates DACI capability on transmission-connected storage schemes, with clear treatment of BESS, 400kV compound and harmonic filter interfaces.

Wider Impact

Supporting the UK's Low-Carbon Future

The scheme supports the transition toward a more flexible, low-carbon power system by providing large-scale battery storage connected to the transmission network. The earthing package reinforces DACI's capability in technically demanding, interface-heavy EHV infrastructure.

Supports large-scale storage connected to the 400kV network
Strengthens stability and flexibility by integrating BESS infrastructure
Demonstrates DACI capability across EHV earthing, bonding and plant interfaces
Captures reusable methods for future BESS and harmonic filter schemes
Builds confidence in complex transmission-connected storage delivery

Conclusion

Technical Expertise, Delivered.

The scheme demonstrates DACI's ability to deliver detailed earthing design for a complex BESS site with a 400kV compound and harmonic filter. The project combines design control, constructability awareness and iterative stakeholder coordination.

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