Integrated electrical and mechanical services provider Marthinusen & Coutts has successfully completed the critical stator rewind for the N’Zilo hydroelectric power station, in the Katanga province of the Democratic Republic of Congo (DRC), following a stator failure.

The company was contracted by State electricity utility Société Nationale d’Électricité for the stator rewind of a 30 MVA 18-pole vertical alternating current synchronous generator at the power station.

Marthinusen & Coutts divisional CEO Richard Botton says the power plant forms a critical component of the power generation network for the entire DRC, where electricity supply is generally under severe pressure and is of great concern, particularly to the mining industry.

Units 2 and 4 were recently refurbished, but Unit 3 had a stator failure that required immediate repair.

“The rehabilitation of Unit 3 at N’Zilo became quite a critical element for the power projects in Katanga. While the average life of a stator is between 25 and 30 years, those at N’Zilo had been operational for 40 years. Generators usually run under arduous conditions, with a high demand placed on the machines, but they cannot run forever.”

Botton adds that N’Zilo had to deal with “ageing and stressed infrastructure that, ultimately, was unable to cope with the demands”.

The long distance between the nearest town and the power station, the difficult terrain and the large equipment posed a challenge for Marthinusen & Coutts, who then decided to undertake on-site repairs.

Fortunately, the company had the necessary skills and equipment in the DRC to effectively carry out the repairs.

However, the repairs required specific testing equipment, which Marthinusen & Coutts had to buy for the repairs to be done. The service provider hopes that the equipment would eventually be relocated to its Centre of Excellence in Cleveland, Johannesburg.

“While the project entailed some serious decisions for us in terms of capital investment, it extends our overall capability and expertise, especially as we grow our business as an integrated electrical and mechanical service provider for power generation and motors,” states Botton.

He adds that diligent planning and the company’s resources in the DRC helped to ensure that repairs were carried out successfully.

Botton believes that Marthinusen & Coutts is well positioned to carry out similar types of critical projects, owing to its resources in Johannesburg and at its Zambian facility.