Switzerland’s national grid company owns and operates the country’s entire extra-high-voltage power network. The overhead power lines are supported by approximately 12,000 steel pylons, each supported by four concrete foundations.

A project to investigate the condition and reliability of these foundations was launched in 2023, with the Swiss firm Brenni Engineering SA contracted to plan and carry out the inspection work on 260 pylons in the Tessin region where it is based. In the course of the work, the company is developing a sustainable concept that can be used for the inspection, evaluation and remediation of pylon foundations across the network – thereby minimising the associated costs and enhancing management control while preserving the value of this critical national asset.

Recognising the need to use state-of-the-art NDT technology to develop the concept, and convinced of the benefits to be gained by using a modern cloud-based platform to store and use the inspection data in a structured asset-management way, Brenni Engineering has teamed up with AQUILA and our partner company, Screening Eagle, to provide the required technology and expertise.

THE CHALLENGE

The 1,040 concrete foundations of the pylons included in the pilot project are about 50 years old, and some display minor surface cracking. Although the foundations are considered to be in good enough condition to serve their purpose for many years to come, it is sensible to investigate the extent and the cause of the cracking and thereby gain an understanding of how it might develop in the future – and if appropriate, to carry out strengthening or other remedial work to counteract any such deterioration.

 On a wider scale, the development of a state-of-the-art, cloud-based “asset management” approach to the inspection and maintenance of pylon foundations can facilitate more efficient planning of inspection and maintenance work, avoid safety hazards and disruptions to service, save costly repairs and prolong service life – all in an environmentally friendly way that reduces the asset’s carbon footprint.

AQUILA’S SOLUTION

Both asset management and NDT expertise.

The first priority was to set up an efficient, reliable and user-friendly system to manage the data relating to all 1040 foundations. For this purpose, Screening Eagle’s INSPECT platform was ideally suited. With each numbered pylon created as an individual asset in the system, and each foundation considered one “spot” to which all data (observations, measurements, photos, etc.) could be attributed, it is easy to oversee and manage the entire inspection and remediation project, in real time if desired, from the comfort of the engineer’s or the owner’s offices. Simply logging in and calling up the “spot” relating to any particular foundation enables the engineer or owner to see up-to-date information and images of that foundation, along with the latest conclusions and any current recommendations.

Then, having commenced the inspections to gain an understanding of the need for non-destructive testing – and what specific questions such testing should answer – an initial series of exploratory NDT tests was planned. This testing had three main goals:

1. to provide insights into the design of the foundations, where details were not available,

2. to help form an impression of the condition of the foundations, and

3. to assist in developing a system for deciding how to selectively use NDT in future, depending on the results of an initial visual inspection.

Four foundations, each belonging to a different pylon, were selected to be somewhat representative of the various designs and conditions of the foundations across the network.

CLIENT BENEFITS 

A holistic approach to addressing the client’s needs – now and into the future.

This project demonstrates well how far structural inspection technology has come, adapting to the information technology of our time – in terms of both the NDT equipment used on site and the cloud-based software that can be used to optimally store and manage all relevant data from anywhere in the world. The use of this powerful technology transforms structural inspection work into an asset management exercise, with numerous benefits for the owner – avoiding safety hazards and interruptions to service, optimising the planning of inspection and maintenance work, and maintaining asset value while saving unnecessary costs.

 While the operation and maintenance of any structure or infrastructure can benefit from the use of a modern digital asset management platform, this is especially true in the case of a system that contains many similar individual assets – such as a power distribution grid – because the uniform nature of the individual assets makes them ideally suited to management using such a structured, highly efficient system. In this case, once the system had been set up and used for the first pylon, repeating the process for all the other pylons became a matter of routine – resulting in increased efficiency and improved reliability. And once inspection work has been carried out, the online system facilitates easy review and discussions with the owner and with other parties (engineers, contractors, maintenance staff, etc.) that will play a role in the future. As these other parties undertake further work or make relevant observations, they can add the details into the online system, continually updating the asset’s “health record”.

In principle, any information or data that may be relevant in the future should be stored on a single easy-to-access and user-friendly platform – and INSPECT makes that possible.

A particularly helpful feature of INSPECT on this project, considering the challenges of finding the assets in hard-to-reach mountainous areas, is the way it can help the user navigate to the pylon locations – once the optimal way to get to an asset has been ascertained, the information can be stored in the system to overcome such access challenges in the future.

To support the asset owner even better going forward, the software is currently being adapted to enable the data from multiple assets (in this case, for instance, where each pylon is defined as a single asset) to be compiled and managed automatically – for example, so that the owner can automatically create an overview of the condition and needs of all of the assets.

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