Apr 2013
Electricity Transmission
Understanding and Mitigation of Hazards Related to Transmission Tower (TT) Bases
Apr 2013
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Health and Safety
The project is to enhance risk assessment methods from the effects of step/touch potentials generated during transient surge conditions. This will allow National Grid to more effectively target resource for mitigation, avoiding unnecessary expenditure and, more significantly, approaches from third parties.
This project investigated the response of towerbase earthing systems under transient conditions and, in addition, considered the effect of transmission lines on nearby pipelines and parallel lines. Such research work helps to clarify the safety issues concerning tower lines and the extent to which these hazards are expected. During the project period, the following deliverables were achieved:

  • Guide notes for monitoring and maintaining integrity of earthing systems including terminal towers

  • Quantification of effect of earthwire isolation on hazard limitation and system performance

  • Quantification of transmission lines on buried metallic objects under flashover conditions

  • Methods for limiting hazards at tower bases using insulation techniques

  • Recommendations for working practices near transmission lines

  • Better understanding of current distribution on tower lines under fault and surge

  • Characterisation of tower lines and associated step and touch voltages under impulse conditions

  • Guidelines for mitigation of earthing hazards along transmission lines.