Major repair work has been completed by Marthinusen & Coutts at Eskom’s Ingula pumped storage hydroelectric plant in what is described as the largest winding installation ever conducted in South Africa.
Marthinusen & Coutts, a division of ACTOM, has completed the stator rewind without incident at the Ingula plant. The contract involved the complete rewind of a 373MVA stator for one of Ingula’s four 14-pole motor generators.
According to Richard Botton, managing director of Marthinusen & Coutts, the 342MW unit is among the biggest in South Africa with a core diameter measuring 5 metres, a core length of 3,2 metres and a rotor mass of 500 tonnes.
“As the stator was located deep in the turbine floor, all the winding was required to be conducted on site,” says Botton.
“In this complicated repair, each replacement coil set was fitted, connected and brazed on-site from pre-manufactured and pre-packed components supplied by the OEM. The most painstaking process, conducted to the highest standards, was the resistive brazing on 1,824 joints.”
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Marthinusen & Coutts undertook extensive prep work
The company carried out the work with a 14-man team, completing the work in November 2018 after 100 days on site. Their extensive preparation included the establishment of training jigs at its Johannesburg facility, allowing customised training for all technicians involved in the mammoth project.
“We also conducted detailed testing, and refurbishment where necessary, of all the winding equipment we would use on site,” explains Botton, adding: “This contributed to smooth and uninterrupted operations, making us self-sufficient in rolling out the contract.”
Working closely with OEMs and Eskom, the company took full ownership of the rewind project from start to finish, he notes. The contract was successfully completed on-time with all test criteria well within specification.
Find information on the Ingula Pumped Storage Scheme here.
“With our in-country expertise, supported by our Centres of Excellence in Benoni and Cleveland, the project showed the world-class capability of Marthinusen & Coutts,” says Botton.
“We could also contribute our specialised equipment and supply chain – elements that often present a challenge to foreign service providers trying to conduct this kind of project work in South Africa,” he concludes.
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