WITH prospects of acute electricity shortages, load shedding and subsequent blackouts posing the biggest threat to attainment of goals, economic growth and sustainable development, NamPower faces a huge task of keeping the lights on in the next few years.
Essentially the mining sector may prove to be the hardest hit if the crisis does arrive and this too would have serious shock effects on the overall economy. Questions of how this can be pre-avoided have been raised and with a mute responses having dominated this inquiry, the answer may have well arrived with South Africa’s fourth-generation 11 MW fully automated direct current (DC) containerised trolley assist substation – the Siemens E House.
One of the six inaugural in-house-developed units has been reported to be heading to an undisclosed Namibia-based opencast mine when it was unveiled last Friday at Siemens’ headquarters, in Randburg.
Some 90 percent of the components of the mobile substation, used to power a fleet of Komatsu 960E trucks with a load capacity of 214 m2 or 327 t, are entirely manufactured by Siemens, including the control panels, rectifier, DC switchgear and alternate current (AC) switchgear. This was up from the historical 30 percent of components used, as part of Siemens’ effort to target international markets in compliance with the specifications and standards of more mature economies.
Each 11 MW fourth generation unit has 1.8 kV DC voltage and up to 10 000 A, with the capacity to operate two 300 t trucks continuously, three trucks simultaneously for ten minutes or four trucks for one minute along the overhead power lines. This reduces the diesel costs of ore truck haulage, which can account for up to 80 percent of total diesel consumption when moving uphill on ramps, by between 30percent and 50 percent, depending on the mine’s gradient.
The substations, which are assembled in Pretoria with components imported from Germany, are housed in a 6 m x 3.3 m x 3 m container and weigh around 8.5 t when fully equipped with the 1.8 kV DC switchgear, rectifiers, 33 kV ring main unit, Siprotec AC protection device and Sitrase Pro DCFeeder protection device. The substation also boasts PLC control, Profinet interface and HMI touch panels.
Critically, Siemens has delivered two units to the Namibian mine in the past two weeks, with the third unit, which was on show on last Friday, set to be transferred this week. The final three completed substations will follow suit in the next couple of months which could bring about a new era in how mines look to manage activities in the coming years.
Confidente. Lifting the Lid. Copyright © 2015