DH Route FEED Study for National Grid Electricity Distribution

The Client

National Grid Electricity Distribution (NGED) is a major UK electricity distribution operator, managing critical infrastructure across the country.

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The Need

NGED engaged Groundline Engineering to conduct a Front-End Engineering Design (FEED) study for the DH Route—a 132kV double circuit overhead line between Chesterfield and Goitside. Built in 1967, the line required refurbishment to meet modern performance, safety, and capacity standards. The goal was to identify an optimal upgrade solution, including new conductors and earth wire, while addressing structural, clearance, and access challenges.

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What We Did

Groundline developed a 3D model of the DH Route using PLS CADD and LiDAR data, simulating the proposed upgrade with AAAC Rubus conductors and Keziah equivalent OPGW . Electrical and structural analyses confirmed the new system could achieve a 217MVA pre-fault winter rating at 50°C, exceeding the existing capacity.

A site walkover identified pulling positions, scaffold locations, and vegetation clearance needs. Non-intrusive Transient Dynamic Response (TDR) testing was conducted on 17 tower legs, with most foundations found in good condition. One tower (DH04) was flagged for intrusive investigation due to shallower-than-expected foundation depth.

Deliverables included detailed clearance diagrams, access maps, and a comprehensive FEED report to support contractor tendering.

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Challenges & Solutions

• Vegetation Infringements: Clearance checks revealed vegetation infringements in all spans. These were mitigated through targeted lopping and removal.
• Foundation Uncertainty: TDR testing identified one tower requiring further inspection. Groundline recommended intrusive testing and geotechnical boreholes at DH04.
• Access Constraints: Dense vegetation and terrain complexity were addressed through tailored trackway planning and vehicle recommendations.

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The Results

The study confirmed the feasibility of the proposed upgrade. All towers met structural and clearance requirements, and the new conductor system significantly improved capacity. NGED received a validated design, a clear construction roadmap, and actionable recommendations for vegetation and foundation management.

This FEED study equips NGED with the insights and documentation needed to proceed confidently with the DH Route refurbishment.

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