SPECIAL FOCUS
New innovations can help eliminate power interruptions, transients and noise that stop production and corrupt data
POWER OUTAGES PREVENTING
Detailing common power quality disturbances in metals and mining facilities and exploring the strategies to overcome them
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n any mining operation, the facility’s infrastructure relies heavily on electric power. However, mining’s harsh conditions, non-
linear loads, extensive use of long cables for mobile equipment, complex grounding and the adoption of ever larger machinery with higher power requirements all challenge the reliability of the power mines depend on to keep operations running 24/7, 365 days a year. Here, we address power reliability in
mines and specifi cally, the increased total cost of operations related to power quality issues. There are four types of power quality disturbances mines commonly experience; and identifying power quality problems is the fi rst step towards developing mitigation tactics that can improve a mine’s safety, reliability, productivity, and cost eff iciency.
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www.engineerlive.com Power quality is critical in mining,
since even short interruptions can lead to equipment damage and production losses costing hundreds of thousands of dollars per hour. Besides downtime, poor power quality can pose safety hazards to workers, especially those underground or in confi ned spaces. Without reliable power, ventilation and lighting systems may fail or malfunction, making it diff icult for workers to see or breathe while levels of combustible gases and dusts increase.
MINING POWER SYSTEMS Mines consume tremendous amounts of power, as much as 120MW per 100,000 tonnes of mined product each day. To get a better idea of power demand, consider the variety of electrical equipment and the diff erent
types of loads in mines. In underground mines, the power system must supply locomotives, drills, shearers, crushers, loading machines, belt and shuttle conveyors, roof bolting machines, hoists, chillers, ventilation systems, and pumps. In surface mining, there are power-hungry rope shovels, drills, and excavators. Extracted materials transported to processing plants encounter large crushers, grinding rolls, semi-autogenous grinding (SAG) and ball mills, as well as exhaust and dryer combustion fans. Understanding the diverse nature and complexity of mining equipment sheds light on why power quality problems are so common. Mines generate electric power
from a variety of sources, sometimes resulting in a patchwork system. When AC grid access fi rst became available, operators began purchasing much of their electrical power from utility
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