Cables Are so Brilliant They’re Boring

By Kathleen Davis, Senior Editor

Cables remain a singular mainstay of power transmission and distribution. Even though Nikola Tesla toyed with massive power transfer through the bare air at the turn of the previous century, the infrastructure of pylons, poles, insulators and cables still dominates electric delivery today.

To get an insider’s view of cables, POWERGRID International spoke in April with Simon Sutton, European end use marketing manager at Dow Wire & Cable. Sutton discussed the trends and research involved in power cabling, what’s on the horizon and why no reader should think of cables as a dull topic.

PGI: Some of our readers think cable is one of the most boring parts of the power industry. What’s most exciting about cable?

Simon Sutton, Dow Wire & Cable

Sutton: Some people may perceive cables as a bit boring, but that’s simply because they are out of sight and generally so reliable. Assets that fail make utility engineers excited, but for all the wrong reasons. What a cable looks like hasn’t changed much in the last 40 years. However, what’s exciting is the number of advancements made during that time, including improvements in cable design, material quality and manufacturing practices. Cleanliness of insulation and semiconductive materials is a good example. It’s no trivial feat to achieve and maintain the extra-high-voltage (EHV) materials that we offer with no contaminants larger than 70 micrometres (µm).

PGI: What are the most important aspects a utility should keep in mind if shopping for transmission cable?

Sutton: The key aspects here are quality of cable materials, manufacture and installation, including commissioning. All of these are required to achieve high circuit reliability and low life cycle costs. If you get any one of these wrong, you can expect poor reliability from the cable in service. It’s also important to ensure that the cable complies with at least the minimum of national or international standards.

PGI: What about distribution cable?

Sutton: It’s a similar story for distribution cable: Focus on quality in materials selection and manufacturing to high standards. The utility engineer’s job is more complicated for medium-voltage (MV) cables than high- or extra-high-voltage (HV/EHV) cables from two broad aspects. First, there are more material choices available in the market and far greater variability in quality if we look globally. Second, current MV cable standards in many parts of the world are not robust enough.

PGI: Dow Wire & Cable supplies materials for EHV, HV, MV and LV power cables. What’s the biggest seller, and where’s it all headed?

Sutton: The volume of material in any cable depends on a variety of factors including conductor size and electrical stress level, so there is progressively more material per meter of cable as you move from LV to EHV. Conversely, cable length installed increases as you move from EHV to LV. Overall it’s a complex issue.

Looking to the future, adequate energy infrastructure is a global issue. Many developed regions are facing the prospect of asset replacement of decades-old power systems, whereas emerging regions are building new networks. All need reliable long life cable.

PGI: What are the biggest hurdles cable makers have overcome recently in the power arena?

Sutton: Similar to many other industries dependent on petroleum-based feedstocks, price is the biggest hurdle. There continues to be strong volatility in feedstocks and cable makers, as well as material suppliers like Dow Wire & Cable, have to price their materials and products accordingly. Another hurdle is simply perception. It goes back to what we talked about earlier. Just because cables look the same doesn’t mean they are the same. Long-term performance matters and cable material selection decisions should be made accordingly.

PGI: What does the future look like for cable?

Sutton: The future is bright. Energy infrastructure needs increase largely in line with economic growth, hence the industry continues to focus on Brazil, Russia, India and China. Also, with so much emphasis on alternative energy, particularly wind farms, we see a lot of growth potential here. After all, no matter how the power is generated, power cables, transformers and other network assets will still be needed to transmit and distribute the electricity.

PGI: A lot of people wouldn’t see cable as having a variety of quality aspects because it’s not all that high-tech. How would you dispel this belief?

Sutton: Simply put, utilities’ needs and expectations for very long-life cables dictate very high-quality cables in terms of performance. As a matter of fact, Dow Wire & Cable invests a significant amount of time and resources on R&D, testing and validation before our materials even arrive at the cable maker. Significant advances have been made in insulation and semicons in recent years, but to the naked eye the materials look the same; insulation is still white, semicons are still black. Where these advances are seen is in the performance of cables made with these materials.

PGI: What area of the European power market will Dow Wire & Cable focus on for the next couple of years?

Sutton: In Western Europe we’ll be concentrating on the MV market, mostly in regard to system expansion and opportunities in the renewable sector. We also expect significant activity in HV and EHV cable. In Eastern Europe and Russia we are emphasizing the importance of high-quality materials for distribution and transmission cables. We are also taking some strategic steps to expand our overall presence in the energy marketplace and will be launching some new products in the months to come.

PGI: Do you see other industry trends?

Sutton: Yes, more and more EHV cable is being installed in both cities and as part of long overhead lines (OHL) away from towns. This trend for undergrounding is also seen at MV and HV. This is happening for several reasons: underground cables often require a smaller right-of-way vs. OHL, are more resilient to weather threats like storms and ice, and enhance property values through better visual aesthetics.

PGI: You’ve just been appointed to CIGRE’s Strategic Advisory Group (SAG) for solid insulating materials. What does this group do? And what is the scope?

Sutton: The SAG for solid insulating materials operates within CIGRE Study Committee D1 (Materials and Emerging Test Techniques) and is responsible, amongst other things, for proposing new topics for study and developing the terms of reference for the working groups. This SAG covers all insulating materials such as polyethylene, epoxies and silicones. I’d be more than happy to receive suggestions for future topics from readers of this article.

PGI: What are you most interested in?

Sutton: I’m currently on a CIGRE working group looking at polymer nano-composites and the possible application of these interesting materials to the power sector. The group has carried out a review of what is state-of-the-art in this field and some round-robin testing of nano-filled silicones, epoxies and cross-linked polyethylene has occurred.

In addition, I’m looking forward to using my background and experience in the industry to work with the other members of the SAG to establish working groups that will benefit utilities globally.

PGI: You spent 11 years with National Grid in the U.K. Does that experience help you in your role at Dow?

Sutton: I held a number of positions in my years at National Grid, and it gave me a good grounding in the way that a utility thinks and operates. I also had the chance to participate in international working groups and research collaborations, which meant I got to meet utility engineers from Europe and beyond. This gave me the opportunity to understand what business and technical factors were driving their utilities. All of these insights help me today work closely with the utilities of Europe.

PGI: If you could impart one piece of advice about cables and insulating materials to the power utility industry, what would it be?

Sutton: I’d like to choose two pieces of advice. For cables, I’d say demand cables that surpass standards, not cables that just meet standards. Material selection is such an important factor in achieving this. For insulating materials, in general, I’d say don’t forget about them. The power industry relies on their performance every day and yet we so often take their performance for granted.

Simon Sutton joined Dow in 2007 after having spent 11 years with National Grid. He has a bachelor’s degree in physics with subsidiary mathematics and a doctorate in physical properties of polymers, both from the University of Reading (U.K). He was appointed to the CIGRE Strategic Advisory Group (SAG) for solid insulating materials in March.

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