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Projects: Projects for Investigator
Reference Number NIA2_NGET0010
Title Non-intrusive Tower Foundation Inspections using UGW (NITFI)
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 October 2022
End Date 30 September 2023
Duration ENA months
Total Grant Value £257,000
Industrial Sectors Power
Region London
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , National Grid Electricity Transmission (100.000%)
  Industrial Collaborator Project Contact , Western Power Distribution (0.000%)
Web Site https://smarter.energynetworks.org/projects/NIA2_NGET0010
Objectives This project aims to adapt the Ultrasonic Guided Wave (UGW) Testing technology to monitor concrete OHL tower foundations. It is a non-intrusive monitoring technique that uses a portable probe, pulser-receiver, and customised software. The probe is mounted on the foundation-steel interface of the OHL tower, and an ultrasonic pulse is sent through it. Reflection of the pulse wave is received by the receiver and analysed by the custom software to detect presence of cracks, changes in thickness caused by corrosion. Given the fact that a number of non-intrusive methods currently exist but do not provide satisfactory assessments on OHL foundation condition, this project aims to explore an alternate method. UGW testing has been chosen in particular as it is portable, and the concept has been successfully proven for the case of corrosion assessment in mains steel gas pipeline. The method was found to have easy to handle hardware, covering larger inspection area and providing instant data relating to condition of the asset with good confidence level. This project aims to adapt the UGW method to apply to OHL tower foundations with modifications such as change in cross section of the probe and associated measurement kit along with lab trials and field trials conducted at locations with different soil conditions to validate the method. 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 6 (low)TRL Steps = 2 (3 TRL steps)Cost = 1 (£257k)Suppliers = 1 (1 suppliers)Data Assumption = 2 (Assumptions known but will be defined within project) The scope for this project is broken down as follows:Task 0 – Array Acceptance Criteriaa. Knowledge sharing on OHL tower foundations and current practicesb. Review of NGETs requirements specific to foundation inspection c. Development of acceptance criteria to assess the performance of a prototype array during the course of the project Task 1 – System Specification and Requirementsa. Review of wave propagation properties and existing standards to aid the design specification of the prototype probe arrayb. Design of prototype linear probe array in order to implement an ultrasonic guided wave (UGW) inspection of the condition/structural integrity of the tower foundation encased steel work (interface between tower leg and stub). This scope of work will require the design and development of the prototype probe array to ensure back-cancellation of the signal, beam focus and suitable excitation frequency to achieve penetration depth. Task 2 – Manufacture of Prototype Arraya. Completion of detailed drawings of the prototype probe array in order to aid manufactureb. Assembly of component parts of the prototype probe array in a laboratory and preliminary testsTask 3 – Laboratory Testinga. Integration of the prototype probe array with data acquisition hardware in order to collect datab. Development of signal processing algorithms/control scripts to analyse the collected datac. Testing the prototype in laboratory conditions and resulting refinement to the probeTask 4 – Field Testinga. Development of Risk assessment and method statement (RAMS) for field trials at trial locations identified by NGETb. Field trials conducted at predefined OHL tower locations covering different soil conditions along with resulting refinements to the probe Task 5 – Demonstrationa. Field demonstration of the refined prototype to demonstrate the capability to detect defects such as cracking and thickness loss due to corrosion The objective of this project is to adapt UGW testing for OHL tower foundation inspection and validate the same through lab and field trials. The following elements will need to be achieved to satisfy the overall objective:To define inspection system requirements, particularly for required minimum defect sizesTo develop a prototype (guided wave) probe array for the inspection of tower foundation legsTo conduct laboratory verification trials of the developed UGW arrayTo trial the method on in-service tower foundations under different soil conditionsTo undertake refinements to the prototype as necessary including analysis of which environmental factors affect the measurement and reportTo conduct demonstration of the prototype at one location after refinements from prior trials.
Abstract Overhead line (OHL) towers have foundations for each tower leg that are typically 4m deep and are a mixture of pad and chimney, and piled designs. To avoid the failure of OHL tower foundations, periodic and accurate inspection of these buried assets is essential. Currently, there is a significant reliance on intrusive methods of inspection involving digging up of the foundations to collect samples which is a carbon and time intensive process. Although several non-intrusive methods exist, getting precise and reliable results with a single measurement is a challenge. This project aims to adapt Ultrasound Guided Wave (UGW) testing to function as a portal inspection kit for condition assessment of overhead line tower foundations. 
Publications (none)
Final Report (none)
Added to Database 14/10/22