Welkom Industrial Controls

System Integration & Control Systems Design

Systems - process or technology specific suppliers

July 2012 System Integration & Control Systems Design

When Harmony Masimong Mine purchased three surface water chiller plants from Trane, Welkom Industrial Controls (WIC) was contracted by Redbase Projects to do the electrical installation and bridge the gap between the Trane plant controllers and the mine’s existing PLC and scada network. The mine is currently running Wonderware Intouch and its standard PLC system is Schneider Electric’s Quantum and Momentum, using Concept.

The first challenge faced was the medium voltage switchgear. WIC partnered with Actom SA to manufacture the 1250 A 12-tier system. A panel had to be designed for two feeders: one feeder was not sufficient for all three plants, but there had to be a method of isolating the feeds. This was achieved with two bus sections on the breakers, enabling the middle plant to be fed from either incomer.

The 6600-550 V transformers were then manufactured and installed and now feed the three LT MCC panels, which were built with energy conservation in mind. The 1250 A panels included 4x22 kW fan feeders, 2x110 kW pump feeders and an additional 75 kW pump feeder, all using Schneider Electric’s ATS22 range of soft starters. A Schneider Electric Momentum PLC controls all starting.

With regard to automation, WIC interfaced through the BACnet protocol of the existing controllers and converted the I/O to Modbus TCP, which could be recognised by the mine’s scada system. The engineers then created the necessary pages on the scada to provide the relevant information to the control room. This included plant overview, instrument and plant trending, manual LT drive control, communication overview and detailed diagnostics.

The building lighting was designed and installed with energy saving in mind, including LED lighting in the offices, MCC room and medium voltage substation. In addition, 4-foot tubes were installed instead of conventional fluorescent tubes. This reduced the potential energy usage by up to 66%. In the main plant area, energy saver high bay light fixtures were also used. In the medium voltage switchgear, the LT MCCs and the two main distribution boards, WIC installed Schneider Electrics’ high quality PM range of power meters to enable the client to monitor their power usage with accuracy.

The installation of the electrical portion of the contract commenced in November 2011 and by February 2012 the plants were operational and producing water chilled to the required 4°C.

Welkom Industrial Controls is currently involved in various other energy saving projects. These include air optimisation on the underground levels of three different Harmony shafts, as well as the automation of seven compressors. These projects are being conducted in conjunction with HVAC International and IST Otokon. Additional to this, WIC offers a variety of renewable power generation solutions including solar grid tie systems, standalone systems and power generators.

For more information contact Llewellyn Coveney-Winter, Welkom Industrial Controls, +27 (0)57 357 5724, llewellyn@wic.co.za, www.wic.co.za

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