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Screening national assets for geohazards

owns and runs a significant network of cables, substations, towers and other electrical infrastructure that is distributed across the country and is sometimes located in remote or challenging conditions that may be vulnerable to hazards. The BGS worked with National Grid to undertake a screening exercise to identify potential geological and flooding hazards that might impact their network.

We were commissioned to provide a hazard assessment for over 30000 assets to determine which were most ‘at risk’ and required further investigation. The locations were evaluated against a number of BGS and Environment Agency datasets, including:

• compressible ground
• collapsible deposits
• flooding
• hazards associated with mining
• landslides
• running sand
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• soluble rocks

The analysis was able to indicate whether there was a hazard directly under, or within the immediate proximity of, an asset (within a 250 m buffer zone around the asset). This data can now be used by National Grid to understand which assets are potentially at risk from specific hazards and to design further investigations or remedial or mitigating action plans.

Site conditions for installing and earthing substations and network assets

and operate thousands of miles of power networks. Earthing is vital for protecting people and animals from electrical currents and also to maintain proper function of electrical systems. Earthing simply connects an electrical circuit with the ground, allowing current to flow harmlessly into the Earth if the network develops a fault or is damaged. We were commissioned to:

• advise on possible earthing array installations given the resistive properties of the ground
• indicate which type of earthing installation system was possible given the physical properties of the ground
• indicate whether current ground conditions for earthing would be adequate given future climate and seasonal variation

Screening buried cables for geological causes of failure

We were commissioned to assess possible correlation between known events of underground cable failure and ground conditions to determine if soil and geology played a significant role in the failure mechanism.

Seventy thousand failure incidents were assessed and compared with a range of soil and geology parameters. Whilst slight correlation with shallow groundwater and certain geological materials was observed, the correlation was too weak to use as a discriminant tool for asset management. We will continue research in this area to determine if other environmental factors are relevant.

Contact

If you want to discover more then please contact Russell Lawley.