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Alstom boosts safety and reliability in high and ultra-high voltage equipment

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Alstoms resin impregnated paper transformer bushing has passed an impressive, first of its kind internal arc test. This test demonstrates the bushings capacity to improve the safety and reliability of power transmission equipment and grids. While this type of test is typical for other electrical components, it is an absolute first for transformer bushings. In developing this new technical solution for high and ultra-high voltage equipment, Alstoms experts aim was to improve safety. Tests on the 420 kV resin impregnated paper transformer bushing prototype were successfully conducted in October 2013 at ZKU, the independent high voltage and high power test laboratory in Prague, Czech Republic. 

Bushings are designed to control the electric field and allow a secure passage of electricity through transformer tank walls. The recent tests demonstrated the resin impregnated paper bushings resistance to explosion in the event of a severe internal electrical fault and subsequent pressure build-up. While rare, such events can endanger staff and equipment. The resin impregnated paper bushing utilises state-of-the-art composite insulators, which are designed to break down rather than explode. This greatly reduces the risk of injury and fire. 

While many traditional bushings rely on a ceramic enclosure, utilities are increasingly turning to composite insulators, such as Alstoms resign impregnated paper, for greater safety. Compared to oil impregnated paper bushings, resin impregnated paper technology is fire and explosion safe. Further, due to the fact that the bushing is oil free, its environmental impact is significantly reduced. 

The internal arc test reproduced the heat and pressure of a fault related to an internal short circuit. To do this, Alstoms 420 kV resin impregnated paper bushing was subjected to a short circuit current of 63 kA for 0.5 seconds. The value of the total injected energy during the test amounted to an impressive 13 MJ the equivalent of a 1000 kg mass launched at a speed of 580 km/h. Captured on film, the bushing successfully resisted explosion thereby passing the safety test. 

In 2011, Alstom was the first in the world to perform an internal arc test on a 420 kV bushing based on traditional oil impregnated paper technology. Today, it has repeated this achievement with the new 420 kV bushing using resin impregnated paper technology. 

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About Alstom

Alstom is a global leader in the world of power generation, power transmission and rail infrastructure and sets the benchmark for innovative and environmentally friendly technologies. Alstom builds the fastest train and the highest capacity automated metro in the world, provides turnkey integrated power plant solutions and associated services for a wide variety of energy sources, including hydro, nuclear, gas, coal and wind, and it offers a wide range of solutions for power transmission, with a focus on smart grids. The Group employs 93,000 people in around 100 countries. It had sales of over 20 billion and booked close to 24 billion in orders in 2012/13. 

Alstom Grid has one clear vision: to develop innovative solutions for a flexible, reliable, affordable and sustainable electrical grid, everywhere. We design, manufacture, install and service the power transmission and distribution products and systems that empower the planets low carbon economy... for now and for the future.

Alstom Grid has over 130 years experience and ranks among the top three in the electrical transmission sector with an annual sales turnover of more than 4 billion. Alstom Grids 19,000 employees are spread across 88 manufacturing and engineering sites worldwide and have one common mission: be our customers trusted partner, from the source to the city.

We are energising a smarter world with Alstom. 

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