NOJA Power has been awarded a contract from Ports Corp. of Queensland (PCQ), Australia, to design, manufacture, test and deliver Low Voltage Motor Control Centers for the Abbot Point Bulk Coal Terminal upgrade. The X25 upgrade program is designed to increase the capacity of the coal handling facilities to 25Mt per annum. NOJA Power is manufacturing Intelligent MCCs, incorporating DOL motor drives and variable speed drives, interfaced to a plant wide control and monitoring system. The upgrade is a major project for PCQ, a government-owned corporation, with engineering to the project provided by Connell Hatch.
The MCCs are designed to AS/NZS 3439.1 and pass comprehensive factory acceptance testing and pre-commissioning process carried out as a joint effort by NOJA Power and Connell Hatch. Monitoring and control of the motor drives is by way of Devicenet and Controlnet protocols over an RS-485 communications bus facilitated by Allen Bradley DYN42R starter auxiliary units. Variable speed motor control is achieved using Allen Bradley Powerflex drives installed together with Line Reactors in fan cooled enclosures mounted separately from the main MCC. This design solution satisfies the 'brown fields' nature of the work, which involves installation in existing buildings and presents equipment installers with significant space constraints. The NOJA Power MCC provides the designer with flexible options including full-depth cable ways used to accommodate the control and monitoring hardware without requiring additional tier space.
The Safety interface to the control system uses Silbus equipment, PILZ relays and Dupline carrier for conveyor safety and control. Each motor drive cell door is fitted with a Voltage Vision device to provide unambiguous indication of an energised motor drive. Earth Leakage protection is provided by the new Terasaki ZS range of Tembreak 2 Moulded Case Circuit Breakers. The ZS range MCCB provides standard thermal-magnetic overload functionality but has the advantage of not requiring a separate EL toroid. Terasaki's Tempower2 ACB's are fitted with AGR-31 over current relays to provide the specified under voltage protection on an individual phase basis. The AGR-31 OCR also provide full power management functions accessible locally from the large LCD or remotely via the MODBUS communications interface, making a separate PM relay and CT's redundant, which assists in minimizing the space requirements. To cope with the harsh environment of a coal handling facility, the MCCs are manufactured with a high Ingress Protection index, all busbars are fabricated using tinned copper and each tier is fitted with oxidation and corrosion inhibitors.