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7
NEWS
June/July 2012 www.esb.ie/em
New age of fault finding
The ‘old hands’ say that finding faults on low voltage underground electricity cables can sometimes be more of a black art than a science. Particularly when you are dealing with cables that have been in the ground for decades.
AGE OLD METHODS are as valid today as they were twenty years ago but new technology is starting to come to the fore to help pinpoint fault locations with increasing accuracy.
Kevin McDowell, NIE Fault and Emergency Manager has been involved with underground cable faults for the last 20 years. In that time he has seen his share of problem low voltage cables. Last year, he was involved in a trial which ‘road tested’ a new device to improve fault location accuracy. Here he tells EM all about it.
What is your top priority when fault finding?
“Safety and speed is always of the essence. At NIE, we manage our fault response in order to restore electricity to customers as quickly as possible. Underground cable faults are obviously more difficult to locate than overhead line faults as you can’t see where the problem is.
“With the introduction of new Street Works Legislation in Northern Ireland, it is vitally important to accurately locate the fault and minimise the need for multiple excavations. This is especially true in a number of towns where urban renewal schemes have seen decorative stone surface footways laid on top of concrete. Due to the safety, inconvenience and cost issues, we aim to minimise the number of excavations required during fault location.”
Are underground cable faults a big issue in Northern Ireland?
“On average we experience about 300 faults each year on our low voltage mains and service underground cable system. There are others on our high voltage network but fault finding techniques generally provide more accurate locations.”
Are you always trying to improve your service?
“Of course, always. There is a lot of pressure from customers to have electricity back on quickly and we work to demanding standards set out by the Utility Regulator.
“Last year we were approached by a local engineering company involved in research and development of a new cable fault locating device. As existing technology hasn’t changed much in 50 years, I wanted to get involved, test it out and assess its ease of use and its ability to locate faults on our low voltage networks.
“The new device provided a simple distance to the fault. This is a great advantage for low voltage underground cable networks, as the combination of single and three phase equipment can complicate interpretation of results from traditional fault locating equipment. We were provided with a prototype to use on NIE cables.”
Did you see a big difference in fault location accuracy?
“Yes, particularly on three-phase cable faults – it was much more accurate and consistent. Fault and emergency engineers Brian Sinclair from Ballymena and Chris Roulston from Campsie completed field trials with the device over several months, using it alongside our traditional equipment. This gave us the opportunity to compare both devices for accuracy, consistency and ease of use.’’
“In one particular case a customer in Antrim had reported a loss of supply to their house, none of their neighbours were affected. We checked fuses at the substation and none were blown. We then went to the customer’s house and connected conventional fault location equipment and recorded a distance to the fault of 2.5 metres. This differed considerably from the new device which gave a distance of 11 metres. In the end up we went with the 11 metre distance as cable faults close to the source are always difficult to locate on our traditional equipment. It turned out to be right.
“We were really pleased with the results, the device is able to provide a definite indication of the fault location within three minutes, it reduced the uncertainty of the fault position meaning fewer excavations to find and repair faults and it enabled customers to be restored quickly.”
Are you going to roll out this technology across the company?
“Changing technology is an expensive business. The cost of rolling out this new technology would be huge and will depend on investment allowances over the coming years.’’
“We aim to replace some traditional devices that are becoming expensive to repair due to their age with the new type in the near future.
However, we are hoping to be able to prioritise the urban areas which would have higher levels of low voltage cable network.”
NIE has 96 Engineers retained on weekly rostered Stand-By Rotas. Almost 90% of customers affected by a power cut in Northern Ireland, have their electricity restored within three hours.
“Of course, always. There is a lot of pressure from customers to have electricity back on quickly and we work to demanding standards set out by the Utility Regulator.
Engineering for the future
TEAMS FROM TWO Belfast schools, Methodist College and Rathmore Grammar, have been putting their thinking caps on to help design a simple way to check oil levels at electricity substations as part of the Sentinus Team Research and Development Programme.
NIE, the team’s industry mentor, asked the students to design a device to enable NIE engineers to check levels of oil at substations. The team’s worked closely with their NIE mentor to produce an industrial quality report outlining their work and conclusions which they recently presented at the exhibition day in Ballymena.
Andrew Cupples, NIE engineer and the school’s mentor, has been impressed with the students’ enthusiasm for the project. He said; “This was a great project that put learning into practise in real business situations. The problem that was given to the team was very difficult but it has been tackled with innovative ideas and a large degree of practical knowledge. The loss of oil can sometimes lead to faults on our network and this device could be a potential solution that we will look at developing.”
Alex Houston, NIE engineer and Rathmore’s mentor added, “There is a particular shortage of technical and scientific skills across a range of industries and NIE is pleased to be associated with a scheme such as this that nurtures scientific interest and creates practical opportunities to develop valuable career skills.”
The Sentinus Team R&D Programme aims to increase the number of young people choosing science and engineering as a career by giving them an insight into STEM research and development working with local industries.
The two schools will present their projects at the Young Innovators competition where NIE will be presenting a prize to the bright sparks at the event who have demonstrated skills in electrical engineering in their project.
Fun at the fair
NIE TOOK A stand at the Royal Ulster Agricultural Society’s Balmoral Show, which was held on the 16th – 18th May. NIE experts were on hand to talk to anyone interested in installing a renewable technology and provided safety advice to the farming community.
The show offered a great opportunity to speak to the farming community about safety and talk to customers about connecting large or small scale renewable technologies to the electricity network.
Balmoral Show Facts
- Balmoral Show is Ireland’s largest Agricultural and Food show.
- This is the 144th show.
- Around 70,000 people attend the show each year.
- It is held at the Kings Hall in Belfast but there are plans to move it to the Maze site outside Lisburn next year show
