Marthinusen & Coutts, a division of Actom, has been awarded the contract for a second 70 MVA synchronous condenser unit for the Société nationale d’électricité (SNEL) in the Democratic Republic of Congo (DRC). The latest contract forms part of Marthinusen & Coutts’ long-term strategy to become a preferred integrated electrical and mechanical services provider for the mining industry and other industrial sectors in Africa. It commenced work in March this year and is aiming for completion by December.
Richard Botton, Divisional CEO, Marthinusen & Coutts said “Our initial contract was a stator rewind for Unit 1, in addition to some minor repairs to the pole coils and complete damper (amortisseur) winding change out. Based on the success of the first unit, we were awarded the second unit. We have completed the stator rewind for Unit 2 and are in the process of manufacturing four new pole coils and reconditioning a further four in our Cleveland, Johannesburg premises.”
“This is a significant achievement and boost for Marthinusen & Coutts’ presence in the power generation industry in Africa.”
“What gives us the leading edge in terms of these contracts is that we can leverage the other companies of the Actom Group to provide us with additional manufacturing capability and expertise. For, example the group has its own laminations department. We are utilising a Group company to manufacture the actual pole shoes while we ourselves manufacture the pole coils, with the final product assembled in our premises. This not only speeds up the manufacturing and integration process but also ensures rigorous control of quality and costs,” Botton explains.
Marthinusen & Coutts had to integrate a range of other suppliers and OEMs in this complex project. The stator coils were imported from National Electric Coil of Texas in the US, with additional components sourced from GE Canada. A modular arrangement was adopted due to the size of the machines, with full assembly taking place on site.
“The rotor components will be delivered this month while the assembly is earmarked for November,” Botton confirms.
The synchronous condensers are critical components of the DC/AC converter station in Kolwezi in the DRC. Power is transmitted from Inga hydroelectric power station in the north, and converted from AC to DC. This is then transmitted to Kolwezi and converted back to AC, with the power feeding the energy-intensive Copperbelt in the Katanga Province.
The synchronous condensers supply the necessary reactive power, which cannot be transmitted via the DC transmission line nor provided by the converter station. The inertia of the rotating assembly of the condenser provides the necessary energy to stabilise the power system in the region, which aids the overall stability of the grid.
The condenser has a stator inner diameter of 2.4 m and a core length of 3 m, while the rotor weighs 95 t and the stator weighs 98 t. This immense weight and size meant that Marthinusen & Coutts had to supply an on-site solution for SNEL. Challenges included the total lack of facilities on site, with no access to either cranage or workshop facilities.
All the necessary equipment and tooling was shipped up from Johannesburg in four containers, which Marthinusen & Coutts will leverage over the long-term to provide an integrated service for power generation and mining clients in Africa.
“With the constraints on power supply being experienced in the DRC in particular, we are now in a unique position to become a preferred solutions provider for such critical projects. This means our customers will have access to our technology, skills base and experience in a one-stop service,” Botton concludes.
