High Voltage

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MEP Middle East speaks to newly-appointed Ducab HV Cable Systems CEO Jon Vail about the JV’s plan to make the UAE self-reliant in terms of its HV requirements.

At present, DEWA is contracting out most of the UAE’s high voltage (HV) cable requirements to international players like ABB of Switzerland, Areva of France, Siemens of Germany and Riyadh Cables of Saudi Arabia. Ducab HV Cable Systems – a joint venture between DEWA, ADWEA and Ducab – aims to slash supply-chain costs and lead times by meeting all the UAE’s requirements locally.

Its products will range from 66 kV to 400 kV, covering the highest voltage used in the GCC at present, and hence becoming the region’s first dedicated high-voltage facility. “We will focus on 66 kV and 132 kV cables in our initial start-up, and then move gradually onto 400 kV, where the test cycle is about one-and-a-half years,” says Vail.

“Ducab currently supplies 50% of the UAE’s low- and medium-voltage requirements. Once fully operational, Ducab HV Cable Systems plans to sell over AED1 billion worth of cable and associated services annually, of which about 60% will be consumed in the UAE. The remainder will be exported to the GCC and nearby Asian and North African areas,” says Vail.

The total cost of the new facility is AED500 million, including working capital. It is being built on a 22 000 m² area adjacent to Ducab’s existing facility in Jebel Ali.

The groundbreaking ceremony was in November 2009, with Khansaheb as the main civils contractor and MACAir as the main MEP contractor. The piling contractor was Dutco Balfour Beatty, while the new facility was designed by Holfords, the architectural division of Hyder Consulting.

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“From a construction point of view, the factory will be completed early next year, by the end of January. Khansaheb has agreed to a time-saving schedule for us to install the machinery in parallel. This will allow us to start installing machines probably by Q2 and Q3 this year. Some of the machines have arrived already, so we just need to get the foundation details sorted out on-site,” says Vail.

“All the equipment has been sourced from major European companies. It is very similar to the equipment we have already, only bigger. The lead time is ten to 14 months. The build time for the factory when we started was only 12 months, so we had to order the equipment in advance. The equipment defined the size of the building. It is not as if we have a building of a predetermined size and will then try and fit everything in; the building was designed to accommodate the specific equipment we need,” says Vail.

It is these specific requirements that have resulted in some specific architectural features of the new facility. “It is unusual for a factory because it has a very tall tower over 150 m high, or the equivalent of a 40-storey building. This is necessary for the vertical extrusion process, which we think is the best way to make high-quality cable. There are alternatives involving horizontal extrusion, but we do not think the quality is as high. This means we have invested more capital in the facility itself, but the end result will be a better-quality product,” says Vail.

He points out that the conductors of these 400 kV cables are 2 500 mm², which is a thousand times bigger than a standard household wire. The reels these cables are wound onto are 5 m in diameter.

“The major issue with such big cables is the electrical stress, which is just voltage divided by distance. More stress means that the slightest weakness or defect can cause the cable to break down – and no one can afford to take a risk with these cables.

40-year lifespan

“If a building wire does not work, a light goes out. If a low-voltage cable fails, a street may be without power. However, if one of these high-voltage cables goes wrong, you take half of the city out, so you cannot afford to take any risk.” This is why these cables, which are designed to be in use for 40 years, require a one-year test as a representative sample of the intended lifespan.

Vail explains that vertical extrusion is the preferred method for insulating high-voltage cables.

“On a medium-voltage cable, say 11 kV, you may need up to 3.5 mm of insulation. Then if you go up to 400 kV, you need 40 times that. Thus you have to reduce the overall size of the cable by making the insulation thinner, which conversely increases the electrical stress. The real challenge is to be able to make this layer withstand such added stress, which means the extrusion conditions have to be absolutely pure and precise. The good thing is that Ducab, right from the outset, has always had a reputation for quality. This then is really just going that one step further,” says Vail.

“Once we have installed the machines, there is still commissioning to do, and of course there is quite extensive quality testing. Without the quality being good, we will not let it out of the factory. We are building a laboratory facility specifically for high-voltage testing, including a Faraday Cage, which is like a big metal box to stop any interference from radios and mobile phones, for example, so we can pick up any potential defects in the form of very tiny electrical impulses. In the future we hope to use this laboratory for facility for R&D work in collaboration with universities,” says Vail.