A locally manufactured switchboard was recently supplied to a gold producer in Gauteng, in a manner that was aimed at minimising disruption to the plant.

The choice of a Zest WEG MTW05 medium voltage (MV) switchboard was based on the panels’ compact dimensions, safety features and internal arc classification, notes Zest WEG executive Bevan Richards. With a 17.5 kV voltage rating, basic insulation level 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 was done to avoide extended downtime, which would have resulted in costly lost production, explains Richards.

“The project consisted of numerous phases, including the addition of a MV power factor correction system (PFC),” 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, 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.”