The Client:
National Grid Electricity Distribution (NGED) in the UK is the regional electricity distribution division of National Grid. It’s the UK’s largest electricity distribution network, serving 8 million customers, with a distribution area of 55,500 square kilometers and 6,500 employees.
Their Needs:
The Chesterfield – Annesley (HR Route) is an existing 132kVdouble circuit overhead transmission line which passes the proposed Newtonwood Solar Farm site in West Yorkshire, in the North-East of the UK.
A single circuit point of connection (PoC) was required to accommodate a new substation compound for the site.
Following the completion of a feasibility study, National Grid Electricity Distribution (NGED) engaged Groundline to conduct the full detailed design works of their chosen option: the installation of a new through condition terminal tower, replacing the existing structure.
Groundline has undertaken dozens of connection studies for NGED in previous years, creating a great working relationship to enable efficient delivery of these popular route modifications.
What We Did:
Groundline was required to provide a full construction package including:
• A model in PLSCADD showing the new tower, complete with structural & foundation analysis.
• Internal & external (in-span) clearance checks.
• Sealing end platform load checks.
• Transient Dynamic Response (TDR) testing of adjacent structures.
• Insulator drawings for the phase wire & earth wire.
• Line profiles.
• New foundation design and drawings.
• Geotechnical investigations comprising of boreholes at the new tower location to obtain soil parameters for foundation design purposes.
Challenges
During construction, it was identified that the underground cable had been installed incorrectly by an external contractor, resulting in 2of the 3 phase colours not matching the proposed overhead line (OHL) design. It would have been a massive undertaking of time and cost to remedy this, so the Groundline team remodelled the OHL arrangement, undertook checks, and issued anew construction package in an arrangement that matched the cable phasing.
The Results:
Groundline provided NGED with a fully compliant point of connection to their new substation compound, within budget and ahead of time. Our nimble response to their installation issue ensured the connection was delivered as planned, avoiding any costly late operational penalties.
