#InsideDCDYNAMIC – James Oxford

Alongside two postdoctoral students from Manchester, we are ageing crosslinked polyethylene (XLPE) under mechanical and thermal stress to see the effect on DC electrical tree initiation and growth, which is a key breakdown mechanism in HVDC cables. Alongside this we are testing the effect of in situ mechanical strain on DC electrical treeing for both the static and dynamic case, and testing model cables under the expected electrical stresses with dynamic mechanical bending for 1.5 million cycles. I’ve handled the design and construction of bespoke rigs, the ageing of samples, and had my share of HV electrical testing. I am also attempting to create an embedded soft or liquid-like electrode which can flex with the polymer under mechanical strain. These electrodes would prevent the creation of voids or loss of electrical contact during applied mechanical strain which is common with inserted steel needles. These soft electrodes have the potential to improve existing electrical treeing methodologies and, through the removal of the airgap at the needle tip, challenge the leading explanations for the fundamentals of electrical treeing.

We all know climate change is a huge issue which will not only affect our lifetimes but that of anyone we’re hoping to bring into the world. DC dynamic cables are a key technology for unlocking the offshore wind capacity of the world’s more treacherous waters and expanding our renewable energy production, lowering our dependance on fossil fuels. While I have pursued physics and engineering my whole life, chemistry and materials were subjects I was interested in but left behind. Having the opportunity to further your understanding of topics which you are interested in, while knowing your niche topic could one day contribute to something much bigger – all as part of your day job – is a privilege I very much appreciate.

Reliable subsea power transmission in the GW scale can be a significant challenge for static cables. When we introduce floating substations, we also introduce the dynamic cable section. The combination of electrical, thermal, and mechanical stress on XLPE has not been investigated, and may yield a mutually destructive relationship. Even in a perfectly made cable a defect may arise overtime, and provide a site for electrical tree initiation, leading to premature cable failure. This research provides an opportunity to delve into the fundamentals of electrical treeing, which are still unexplained phenomena, and further evaluate the behaviour and effectiveness of state-of-the-art polymeric cable insulation for HVDC GW power transmission. The results should confirm XLPE’s suitability for these cables while highlighting exactly how future materials can improve upon it.

Collaborating internationally with other institutions has been an exciting development. Presenting and discussing in monthly meetings to people far more experienced than myself from all over Europe has significantly accelerated my personal development. Joining the project after my bachelor’s degree at 22 years old I understood the amount of work that lay ahead of me just to get in the game. To be able to now confidently discuss the possible fundamental behaviours of our findings at length with experts in the field is both the most challenging and rewarding aspect of working on the project.

From my previous experience in mechatronic engineering working almost exclusively in low voltage, to now working in power transmission under extra high voltage; the project has provided me the opportunity to drastically improve both the breadth and depth of my skillset across all areas; From the basics of presentations and communication to the more complex understanding of nanomaterials and their behaviours under high voltages (and the practical skills for building and running those experiments), involvement has driven my personal development across the board.

Yorkshire tea, always. Strong with a dash of milk. A black coffee in the morning to get things going.

Both, then a big rest at the weekend.

Autumn for me. Lots of birthdays, Halloween, bonfires, fireworks, the run up to Christmas, late nights with mates, hot drinks, cool dry days, and the best comfort foods. You’ve got longer sunsets, purple hills over the wheat fields, and everyone’s winding down for winter. Perfect time for a pub garden and a steak pie in the countryside.

It’s certainly a challenge, but I like to squeeze as much as I can around the working day. I like delving into older music, finding obscure records or songs with a great story behind them or a unique sound to them. I play a little guitar and piano though admittedly not as much as I’d like to. I enjoy cooking, drawing, and painting, and for exercise weightlifting, hiking, or fishing. I’m currently redecorating my house and designing my next tattoos. On nights when I’m not feeling too productive, I’ll hop on a game with some old friends from home. During my undergrad I helped to start and ran the kitchen for a student volunteering group in Stockport which cooks 50+ meals a session for families from in-between housing who suffer from homelessness or domestic issues. Originally running a session once per week, I’ve had to hand over the project to younger students so I can focus on my work, though I still attend as a volunteer cook. I’ve also gotten into fishing lately but will let you know when I catch something.

I’ve just finished ‘Babylon: Mesopotamia and the Birth of Civilization’ by Paul Kriwaczek. Its not exactly a light read but it’s fascinating to see how little people have changed over 10,000 years.