The dry-type transformers, with a total rating of more than 397 MVA, are scheduled for installation in the South African hard-coal-fired power stations Kendal, Majuba and Matimba. In terms of rating, the Kendal power station is the world's biggest coal-fired plant.
ABB's project manager in South Africa, Herbie Collignon, explains that Eskom requested a turn key solution for its variable speed drive (VSD) application in three of its major coal fired power station. For this reason Eskom opted for the RESIBLOC dry-type transformer as the preferred solution for the application. The selection was based on the following principals:
- Proven reliability and track record world wide
- Low maintenance life cycle cost
- Conformance to International standards and tests
- The equipment will suit the harsh operating environment
- Equipment standardization across Eskom
"This protects them from inclement weather conditions, like heavy rain or strong winds. Moreover, the transformers are interchangeable, so that the customer can deploy them flexibly in the three power plants to suit the load situations involved," said Collignon.
A total of three RESIBLOC transformers were each filmed over several days of acceptance testing in Brilon, with a live fed to the customer online. An inexpensive and convenient alternative: those responsible for the project in South Africa didn't need to embark on the lengthy flight to Germany. "We were able to clarify any questions arising directly, or afterward in a telephone conference", relates Gabriele Luckey, the responsible project manager in Brilon.
The videoed acceptance test was a premiere for the transformer experts from Brilon - but the procedure definitely has potential: "We were very satisfied with this video-conferenced acceptance test. It's a procedure we shall certainly be using quite often in the future - considering also the environmental benefits," added Luckey.
Because of the harsh weather conditions involved, such as heavy rain and strong winds, and the stringent reliability and safety requirements required, the customer opted for the RESIBLOC transformers. When fitted with an IP54 enclosure, the transformers will be protected from the external conditions. Moreover, the air-to-air coolers installed in 16 transformers provide dependable operation even at high temperatures.
Eskom is responsible for generating, transmitting and distributing almost 95 percent of South Africa's electricity - and this country alone accounts for around three-fifths of the total power consumption on the African continent.
The utility company placed an order with ABB in the autumn of 2009 for upgrading energy-efficiency in three of its largest power plants. ABB is supplying its equipment for a complete turnkey package comprising drives, motors and transformers, all the way through to final installation. The order is worth a total of $54 million, and originated in a shared project from ABB in South Africa and in Switzerland. Within this order, ABB in Brilon is responsible for supplying 34 RESIBLOC transformers.
