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Reference Number NIA2_NGET0011
Title Alternative Approaches to Tower Painting Preparation
Status Completed
Energy Categories Other Power and Storage Technologies(Electricity transmission and distribution) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
National Grid Electricity Transmission
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 February 2022
End Date 31 January 2023
Duration ENA months
Total Grant Value £238,880
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , National Grid Electricity Transmission (100.000%)
  Industrial Collaborator Project Contact , National Grid Electricity Transmission (0.000%)
Web Site
Objectives NGET are commissioning a study to investigate the viability of two alternative approaches to preparation of OHL towers for painting. To employ an alternative practice, NGET must be satisfied that there is no risk to working parties of flashover from live conductors and thus the work can be carried out safely. Towards this, the alternate methods would be tested extensively using samples from the network, under HV laboratory conditions.This project will benefit NGET and our stakeholders by committing to deliver a better preparation standard to its towers, using faster and more sustainable methods. It is estimated that if the new practice is proven to be viable, it could be employed on 80-90% of towers on the network (access issues may prevent adoption on 100% of the network). Data Quality Statement (DQS): The project will be delivered under the NIA framework in line with OFGEM, ENA and NGGT / NGET internal policy. Data produced as part of this project will be subject to quality assurance to ensure that the information produced with each deliverable is accurate to the best of our knowledge and sources of information are appropriately documented. All deliverables and project outputs will be stored on our internal sharepoint platform ensuring access control, backup and version management. Relevant project documentation and reports will also be made available on the ENA Smarter Networks Portal and dissemination material will be shared with the relevant stakeholders.   Measurement Quality Statement (MQS): ​ The methodology used in this project will be subject to our suppliers own quality assurance regime. Quality assurance processes and the source of data, measurement processes and equipment as well as data processing will be clearly documented and verifiable. The measurements, designs and economic assessments will also be clearly documented in the relevant deliverables and final project report and will be made available for review. In line with the ENAs ENIP document, the risk rating is scored Low.TRL Steps = 1 (1 TRL step)Cost = 1 (~ £290k)Suppliers = 1 (2 suppliers)Data Assumption = 1 (data supplied by suppliers for analysis) The study will cover:1. Review of literature and standards to summarise all available evidence about the behaviour of HV electricity in vicinity to water spray/dry ice.2. Development of a working hypothesis on the level of risk that can be expected using water spray/dry ice in comparison to atmospheric conditions.3. Agreement of a test arrangement to be deployed within the laboratory.4. Assessment of the effectiveness of the following methods for surface preparation prior to painting:High Pressure Water JettingDry-ice cleaningWire brushing5. An initial assessment of the likely carbon footprint of the above activities.6. Evaluation of the technical/commercial/environmental impact of the differing approaches.Subject to the availability of samples provided by NGET, it is proposed that the above assessment is carried out for the following:Algae removalPreparation of grade 1-3 steelworkPreparation of grade 4 steelwork (required for dry ice cleaning only)For high pressure water jetting: 1. For a given configuration of free-issued water jetting equipment, establish the limits and conditions for which a flashover occurs, when considering the associated switching transients/impulses voltages for the following HVAC ET systems:400kV275kV132kV2. Determine the impact (if any) of varyingatmospheric conditions on the required electrical safety clearance, including varying intensities of precipitation. Lightning events do not need to be considered.3. Provide recommendations on alterations to the configuration/specification of the free-issued equipment to reduce the required electrical safety clearance.For dry ice cleaning:1. Determine the parameters for effective surface preparation; including pellet size, blast pressure and rate, nozzle type, configuration, etc. It is assumed this will be established as part of the deliverable above.For high pressure water jetting and dry ice cleaning:1. Feasibility study covering:Application of the process in an operational environmentSourcing of sufficient quantities of CO2 to allow adoption for NGET assets2. Assessment of the implications of implementing the use of high-pressure water jetting and dry ice cleaning as operational practices. The objectives of this project are to:Assess the viability of high pressure water jetting or dry ice cleaning as viable alternatives for the preparation of entire tower structures.Establish optimal ranges of variables in these methods (conditions related to flashovers in water jetting method and pellet size, blast pressure, rate, nozzle type etc. in dry ice cleaning) for use in operational environments.If found feasible, establish procedures conforming to NGET safety standards, carbon impact and techno commercial aspects relating to these alternate methods.
Abstract Corrosion causes material loss from steelwork on lattice OHL towers, which can be minimised through the application of an optimal painting regime. Approximately 1,200 towers are repainted every year on NGETs network of OHLs. Current NGET policy dictates that high pressure water jetting may only be employed up to a height level with the bend line of a tower (i.e. a height beneath the lowest phase conductors). Above the bend line, preparation requires wire brushing and anti-fungal treatment (where required) due to concerns about the use of high pressure water jetting in proximity to live conductors. This project investigates the viability of adopting alternative approaches for surface preparation of steel lattice towers prior to painting, specifically: High pressure water jetting and Dry ice (CO2) cleaning.
Publications (none)
Final Report (none)
Added to Database 14/10/22