National Grid Gas Transmission (NGGT) aims to move away from predictive asset type modelling towards condition based monitoring of its critical assets. These assets are ageing and many have already reached the end of their intended asset life.
Partnered with two Small Medium Enterprises (Synthotech and Premtech) which have proven records of success in innovation projects, NGGT is seeking to introduce in line inspection of below ground pipework at high pressure installations (AGIs), in order to determine the true condition of these assets. This will allow for pre-emptive fault detection, more targeted planned interventions to be undertaken, thereby extending the life of assets which remain in good condition and cost optimisation.
There is currently no available technology which can in line inspect below ground pipework at pressure above 2Barg. AGIs operate pipework at up to 100Barg. Current methods of inspection for below ground pipework AGIs involve visual inspection via excavation which is both financially and environmentally expensive. As such it does not regularly take place and reliance on survey techniques to target excavations is favoured. These surveys only provide a partial view of asset condition and can be inaccurate leading to unnecessary excavation to investigate potential problems. Not fully understanding the condition of our assets increases the likelihood of an asset failure at a high pressure installation which is also critical to our national infrastructure, such as those which supply power stations.
NGGT has a proven history of developing effective in line inspection technology, evidenced through In Line Inspection (ILI) of pipeline via Pipeline Inspection Guages (PIGs). As such it believes it can develop a robotic in line inspection device which can operate at up to 100Barg. This will allow NGGT to implement an intelligent and proactive asset management strategy, reducing the requirement for inefficient and expensive excavations, extending the life of assets and reducing the likelihood of an asset failure at a high pressure installation thereby securing our national resilience.
Objectives
Traditionally the onshore pipeline industry has only been able to in line inspect high pressure pipelines using PIGs. In line inspection of pipelines provides the most accurate and reliable information on the condition of buried pipelines, other inspection methods external to the pipeline have a number of limitations. This innovative robotic technology will however increase precision in our predictive methods. Ultimately, below ground pipework on AGIs however cannot currently be in line inspected because of a number of engineering challenges associated with complex pipework geometries, lack of access and retrieval points and flow factors.
The project has 4 key objectives:
- To accurately and reliably determine the condition of high pressure below ground pipework at AGIs using an internal inspection robot.
- To generate a proactive, rather than reactive, risk based approach to the management and maintenance of aging assets, based on the knowledge of the actual condition of pipework.
- Minimise the occurence of annual unnecessary excavations and eradicate premature replacement of assets reducing significant carbon emissions and generating cost savings of circa £58m over 20 years.
- Minimise the likelihood of asset failure through proactive asset management, thereby significantly reducing the risk of a high pressure gas release into the atmosphere and the consequential financial, environmental and reputational impact.
Learnings
Outcomes
The purpose of the Project GRAID Network Innovation Competition (NIC) was to design, build and test a robotic platform that can navigate National Grid’s unpiggable pipework during ‘live’ conditions and collect reliable data. By proving the integrity of the pipework the ambition was that expensive and unnecessary excavations and asset replacement activities can be prevented. Following the completion of the four year programme of works, all objectives were met for GRAID with the following key outcomes:
2.3.1 Robotic platform
The robotic platform encompasses the major outcome for the project and includes all of the concept designs, calculations, development sprints and build stages. The resulting output is an operational GRAID robot, Umbilical Management System (UMS), tether, transportation trolley, cable assembly, control desk and kiosk to house the robot operators. The entire platform has been extensively tried and tested and at the end of the project has been handed over to National Grid, ready for operational use.
2.3.2 Launch Vessel
The specially designed GRAID Launch Vessel was designed by Premtech and manufactured by RMA and enables the robot to be inserted into the National Transmission System. The vessel is rated up to 100 bar(g), includes an industry standard quick closure door system,
custom designed rails for the UMS, the through wall shaft for the connectors and significantly the manual pullback mechanism. Ultimately the GRAID Launch Vessel is like a standard PIG trap albeit slightly shorter at roughly 3.5m long.
2.3.3 Offline facility
To test the GRAID robotic platform and launch vessel an offline test facility was required to ensure all the process and procedures along with the hardware itself operated as expected before it was used on the NTS. The DNV-GL Research and Test Facility at RAF Spadeadam was selected as the location of this test rig and following a design phase by Premtech, the rig was built by DNV-GL. The layout which was built using repurposed 30” to 36” transmission pipework included 90° bends, tee joints, a 45° gradient and a vertical section.
2.3.4 Online testing
As part of a separate but parallel activity, NGGT sought to sanction funding outside of the NIC process to build several permanent NTS GRAID connection points. These were located at Pannal Offtake and Bacton Terminal.
2.3.5 Pannal
In order to carry out the first trial of the GRAID robot on the NTS a low risk site was required which offered the ability to test GRAID but without impacting the flow of gas. During the inspection period the output from GRAID included over 1,000 individual wall thickness measurements and several above ground pipe supports analysed in detail to prove the integrity of the pipework encased by the support.
2.3.6 Enhanced NDT
From the beginning of the project it was always envisaged that three online trial locations would be built and inspected, however as the project progressed and further understanding was gained it was decided to carry out a period of Enhanced NDT work to replace one of the online trials. This agreement was made with confirmation from Ofgem and allowed the team to spend some time at the offline test rig in RAF Spadeadam to understand how the Electromagnetic Acoustic Transducer (EMAT) sensors reacted to real defects. The knowledge gained during this time was invaluable as the results from the sensors differ considerably on real defects and the team could record how this was visualised on the output graphs.
2.3.7 Bacton
The final online trial was completed at Bacton Terminal and was seen as a significant step forward for National Grid in accepting internal robotic inspections as a viable option. The inspection period was successful with a full 100 m survey, hundreds of wall thickness measurements, location of previously buried assets and video records of 36” ball valve actuation at site pressure.
2.3.8 Condition Model
A significant part of the original Project GRAID bid surrounded how the data thatwas collected would be analysed and modelled to provide a reliable decision tool for National Grid. The output model takes all the existing data sources available and combines it with known measurements from GRAID to define areas of corrosion susceptibility and the likely corrosion growth rates. This model can be re-run depending on the location in interest with a colour coded output map to be used by the National Grid Asset Health team. As the information and knowledge is built up over multiple connection points the accuracy improves and inferences can be made to prevent unnecessary excavations and early asset replacement.
Lessons Learnt
Sharing the stories, updates, events and news regarding Project GRAID has been a significant part of the NIC journey from the very beginning. With such an ambitious project, many people have expressed a wish to follow the progress either from an academic, commercial or purely curiosity point of view. The following channels have been used to spread the message about
Project GRAID.
12.1 External Channels
The central point for all GRAID communications is the website (www.projectgraid.com) which was set up with the sole purpose of allowing everyone to read about the project, understand any progress that was made and importantly get in contact if required. Based on a WordPress platform the blog style allowed the GRAID website to be split into articles either on News, Documents or Events.
By using this popular platform, the team had access to a huge variety of features and tools including picture sliders and the ability to format the content for viewing on a mobile device. The website receives between 50 and 100 individual hits a month and between 150 and 200 page views and peaks in this trend have been noticed after significant external events. While most of the traffic is from the UK, the website has recorded interest from around the world
including USA, Norway, Thailand, Australia, Canada and the Asia Pacific region. These
statistics show how far a project such as GRAID can reach and the global challenge
that it is addressing. The website also includes a function to be able to subscribe to the GRAID newsletter. The newsletter, which is produced and sent via the MailChimp system, is distributed during the first week of every month and summarises the articles that have been
uploaded to the website in that period. The distribution list has grown throughout the
project and now totals over 2,000 contacts from a variety of sources including academic
institutions, private companies and National Grid. Again, the distribution of this newsletter matches the website with most interest from the UK, Europe and US. The website can also share articles to other social media outlets such as Facebook, Twitter and LinkedIn. These methods have been exploited to allow people to follow the progress of the project. Finally, the external National Grid website has included articles on Project GRAID to promote the work
being completed.
12.2 Internal Channels
Internally to National Grid there are a variety of channels which have been exploited to share messages across the business. A regular email called ‘GTO News’ has featured many of the major milestones for GRAID and is sent to everyone in NGGT. Several pages of the company intranet have also been produced for larger articles about the robot along with slides which feature in a monthly ‘Team Talk’ for all managers to share with their teams. Via the Innovation
team, Project GRAID has been able to attend internal Operations stand down events with a display stand to show the 3D printed models of the robot for context and to explain the project.
See section 12 & 13 of closedown report
