AWJ13: Rio Tinto Alcan ISAL Smelter in Iceland Expansion Project

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Rio Tinto Alcan ISAL Smelter in Iceland Expansion Project

220kV AIS Footprint

Introduction The power intensive industry, which is characterised here as manufacturers needing more than 7 MWh/t of their output product, is highly dependent on the technological development of the manufacturing companies in the areas of products conveying, transforming, switching and controlling power at medium and high voltages. It is of mutual benefit to these companies to cooperate for continuous improvements of quality and efficiency of their products and processes. For Rio Tinto Alcan (RTA), HSE (HealthSafety-Environment) aspects of their equipment and production processes are paramount in their evaluation for construction and operation potential. The engineering and production technique of ABB in the field of SF6 insulated switchgear, has presently reached such a level that smelters

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with high HSE-demands combined with high demands of availability and reliability of equipment, can take confidence in choosing medium voltage switchgear.

economical considerations in many cases for voltage levels of 33 kV and higher.

The specific properties of SF6 are further outlined below.

SF6 can be heated to 500째C without decomposition in the absence of catalytic metals. SF6 is nonflammable. Therefore, the risk of ignition caused by an SF6 switchgear malfunction is practically zero, as well as the risk of damage caused by an external fire is as limited as possible. The fault current interruption capability of SF6 is excellent. In its pure state, SF6 is nontoxic, and this is regularly confirmed on new gas prior to delivery, by placing mice in a gas mixture of 80 % SF6 and 20% oxygen for a period of 24 hours (biological test recommended by IEC 376).

Electrical Properties The excellent dielectric properties of SF6 are attributable to the electronegative character of its molecule. It has a pronounced tendency to capture free electrons forming heavy ions with low mobility, making the formation of electron avalanches very unlikely. The dielectric strength of SF6 is about 2,5 times higher than that of atmospheric air under the same conditions, and this leads to space demand of only 1/10th of conventional air insulated switchgear. This fact is decisive for

EPC AND INDUSTRY PROJECTS

Chemical Properties


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AWJ13: Rio Tinto Alcan ISAL Smelter in Iceland Expansion Project by GMC Online - Issuu