Experience over the last year has taught South Africans the importance of a stable, reliable power supply. An extensive contract awarded to GE Consumer and Industrial in January 2006 is nearing completion, and will go a long way towards ensuring Eskom is able to reach its goal of supplying uninterrupted electricity in South Africa.
When Kriel was completed in 1979, it was the largest coal-fired power station in the Southern Hemisphere. One of the first stations to be supplied with coal from a fully-mechanised coal mine (from both underground and surface open-cast operations), Kriel is unique in that each turbine generator set is separate, as opposed to Eskom's other stations, where all the turbines are housed in a single turbine hall.
"Thirty years is a long time in the electricity generation business, and the refurbishment had become essential," says GE Project Manager Fred Barkhuizen.
"The replacement of the equipment originally installed in most cases had become obsolete and to extend the life of the station this had become a necessity.The overhaul by GE Consumer and Industrial extends the station's period of service by 25 years," explains Barkhuizen.
There are six units at Kriel, all of which feed into the national grid. Eskom wanted the units which were most in need of refurbishment to be replaced as quickly as possible, but they had to be dealt with one at a time to keep power generation and supply optimal. GE Consumer & Industrial was tasked with replacing the Low Voltage Switchgear with new technology.
Low Voltage Switchgear motors drive different applications in the turbines, such as cooling fans and heating systems for water.
"The low voltage switchgear being supplied and installed at Kriel is fully-withdrawable - designed, manufactured and installed in Eskom power plants. (The first Eskom contract for this type of equipment was Majuba Power Station which was commenced in 1992 and completed in 2000.) GE Consumer & Industrial was the first manufacturer in South Africa to supply it," says Barkhuizen.
"The biggest benefit with this type of switchgear is that it cuts down the outage time. So if any maintenance is required the draw-out drive can be replaced with another, limiting any stoppage in the plant and the drive to be repaired can be taken to the workshop and done there."
The process followed during refurbishment was designed to keep the power station ticking over as efficiently as possible. While each unit was still being assembled at GE Consumer & Industrial, Eskom started with the cabling at the power plant. A team of Eskom personnel was sent to GE Consumer and Industrial for about two months' training, with hands-on, on-site work at GE Consumer & Industrial to learn about the operation of the equipment. This empowered Eskom employees with skills and experience, which is not only of direct benefit to Eskom but also to the country, broadening the skills available to other potential employees in the future.
"They get first-hand knowledge of how the equipment works, which can help them with fault-finding if it occurs after the plant is in operation," comments Barkhuizen. "This training will improve productivity, cutting down the maintenance time, which of course can affect the plant's efficiency and productivity."
GE Consumer & Industrial handed over the equipment after functioning and operational testing of switchgear, which was then taken apart and transported to Kriel for re-assembly. Eskom connected cables to the switchgear in phases and tested each section. GE Consumer & Industrial was intimately involved with the process, with site engineers standing by when Eskom energised the plant.
"Unit 6 was installed and commissioned in July 2006, followed by Unit 1 in August 2007. Unit 5 is currently being installed and commissioned. Kriel Power Station will be all set for another 25 years of power generation to South Africa," Barkhuizen concludes.
Ends
About GE - Consumer & Industrial
Industrial
The Industrial division of GE- Consumer & Industrial in South Africa is a leading supplier of products and solutions for the safe and efficient distribution of electrical power for industrial, commercial & residential facilities. The business provides products and solutions for industrial applications such as motors, drives and automation applications. Their systems and products are applicable in the iron and steel, paper and pulp, materials handling, water and public utilities sectors to mention a few.
Power Controls (the European arm of the Industrial division) operates a facility in South Africa for Low Voltage Switchgear and Motor Control Equipment, and distribution of electrical components.
Their Multilin range of equipment is widely used in the management of power systems in South Africa. The Industrial business furthermore serves the requirements of oil industry facilities in Nigeria and Angola.
About GE
GE is a diversified global infrastructure, finance and media company that is built to meet essential world needs. From energy, water, transportation and health to access to money and information, GE serves customers in more than 100 countries and employs more than 300,000 people worldwide. For more information, visit the company's Web site at http://www.ge.com. GE is Imagination at Work.
Justus Waimiri
Kendal Hunt