October 30 - Vanguard, South Africa's heavy rigging and lifting specialist, is currently completing a turnkey contract to transport transformers, reactors and accessories from port to various sites throughout the country. The items were shipped from manuf
This contract forms part of a larger project being carried out to upgrade the electricity grid to meet rising demand for power in South Africa.
The project includes transportation and installation of six 667MVA single phase power transformers, each weighing 255 tons with an additional 60 tons of accessories, and 15 of133.3 MVA single phase reactors, each weighing 82 tons. The equipment is destined for power utility Eskom's substations in the Free State and Mpumalanga provinces. This contract was awarded by Sumitomo Corporation, a main contractor to Eskom.
The electric substation equipment is to be installed at each 765 kV transmission grid substation which is supplied with power from multiple coal-fired power stations in Mpumalanga.
The project has been underway for two years with Vanguard's first step researching and establishing a viable transport route.
"This included a comprehensive route survey and bridge analysis to ensure that the weight could be handled, as well as ensuring there were no overhead structures along the way," says James Robinson, Vanguard project engineer. "We also used a liaison that managed Telkom, the country's fixed line operator, and Eskom for us, to ensure that power and communication lines could be lifted or lowered accordingly."
Vanguard designed a trailer specifically to suit the transport requirements of the project, with the transformers measuring 10m in length, 4.9m in width and 5.25m in height. In order to optimise the trailer, Vanguard had to procure additional equipment. The trailer is 30m long and 5m wide and is driven by three 610hp Mercedes Benz horse tractors in a push-push-pull configuration.
"However, a huge obstacle presented itself just before the first shipment was due to arrive," says Robinson. "The proposed and approved route included portions of the N2 towards Pongola in the KwaZulu-Natal province which was due for road works as part of an upgrade project. The road was closed in February and would remain so for the next two years.
"Working on a deadline we investigated other routes but nothing suited our purposes. But after some research and some creative thinking, we opted for a route through Swaziland."
The route runs parallel to the N2 and includes a highway that is relatively new and in good condition. It also has no bridges which ensured that Vanguard was able to obtain clearance relatively quickly.
"There was a lot of additional pre-preparation work which involved us working with the Swaziland's communications company and electricity company to ensure that the telephone and power lines are not an issue."
"Once the first four transformers arrived in Richards Bay, we handled all the customs clearing and harbour staging," says Robinson. "The transformers are extremely sensitive pieces of equipment and cannot be bumped or jostled in any way. We elected to use gantry equipment, which is safer and lessens the likelihood of bumps and knocks. We also used a staging trailer within the harbour which is smaller and more mobile. Once offloaded, the transformers were stored in a lay down area. This ensured efficient handling, allowing us to offload all four in one day."
The remaining two single phase transformers will be arriving by December 2009.
From the harbour, the transformers are being transported to the various sites where they will be offloaded and slid into final position. This involves turning each transformer 90 degrees before sliding and final
alignment. To accomplish this, Vanguard designed and built a turntable to make the turning process safe and impact free.
"The offloading is accomplished using a combination of the turntable, 1000 ton gantry system and jacking tools. While using gantries in this type of application is not common practice, especially with transformers of this size, we established that this was the best method for the project, as it is safer and quicker."
The project is expected to be completed in 2010.