IN a process that minimised disruption to the customer’s plant, Zest WEG has supplied one of its locally manufactured MTW05 Medium Voltage (MV) switchboards to a gold producer in Gauteng.
According to Zest WEG executive Bevan Richards, the choice was based on the panels’ compact dimensions, safety features and internal arc classification. With a 17.5 kV voltage rating, basic insulation level (BIL) of 95 kV and a fault level rating of 31,5 kA, the switchboard also has a high internal arc classification of 31.5 kA BF ALR 1sec
“The changeout was facilitated by an extension of the substation to allow both the existing panel and our new MTW05 MV panel to be accommodated in the same room,” says Richards. “This allowed for our panel to be installed and energised, so that loads could be moved from the existing panel to the new panel at opportune moments.”
The customer was able to complete the termination of cables from the national utility, from the standby generator set and from numerous feeder overhead lines in this phased approach. This avoided hours of downtime, Richards explains, which would have cost the customer dearly in terms of lost production. The job was conducted after detailed engagement with mine management, to arrive at an optimal solution within the operational demands of the plant.
“The project consisted of numerous phases, including the addition of a MV power factor correction (PFC) system,” he says. “With the plant planning a number of upgrades, the new state-of-the-art panel provides a safer solution that will accommodate all the required modifications and extensions going forward.”
The order included the supply of a battery tripping unit (BTU), a cabinet for tools and equipment, and a new distribution board, as well as the completion of internal control cabling. Zest WEG also supplied, installed and commissioned a fire suppression system inside the MV substation and PFC room.
“Another element of our solution was to give the customer enhanced monitoring capacity, by fitting the incoming panel with a power quality meter with GPS and GPRS capability,” says Richards. “This allows for the off-site monitoring and recording of power quality and energy consumption, so they can pick up any spikes in the grid supply that might expose the plant to damage in the long term and determine the cause of power outages.”
