S&C PureWave DSTATCOM Solves Voltage Flicker Problem for Mining Operation

Power quality problems continually arise in various industrial applications. An S&C PureWave DSTATCOM Distribution Static Compensator improved power quality for a mining operation, as well as helped to increase the capacity of the local utility's distribution feeder line, providing consistent power to all customers on the feeder line.

The Challenge: 800 Utility Customers Demand Reduced Voltage Flicker

An Indiana mining operation utilizes powerful rock crushers to produce raw material for agricultural and construction use. This equipment was causing significant voltage variations on the feeder from the local electric utility. More than 800 other customers served from the feeder were experiencing voltage flicker far exceeding the 4% maximum considered acceptable. The company could either operate at less-than-full capacity or fund the building of its own distribution substation. Neither option provided an affordable solution.

Technical Considerations

The heavy mining equipment takes material a foot or more in diameter and reduces it to five inches or less -- or even powder, depending on the application. Seventeen 480-volt motors, ranging in size from 75 hp to 250 hp, combined with a considerable number of fractional horsepower motors, are used in the machinery for this operation. The simultaneous starting of this large motor load caused voltage variations of 8% to 12% on the feeder serving the mining operation and the other customers.

The Solution: A Cost-Effective Static Compensator

An S&C PureWave DSTATCOM® Distribution Static Compensator rated ±2 MVAR was selected and installed along with a 2-MVAR capacitor bank in parallel. Together, they provide a controllable reactive range of --2 to +4 MVAR. The PureWave DSTATCOM is a medium-voltage system that protects the distribution substation from problem loads by means of reactive power management.

The PureWave DSTATCOM extends the reach and increases the capacity of distribution feeders by up to 50%, improving power quality for remotely located users. Systems are modular in design and applicable to loads up to 60 MVA.

Results: A Good Neighbor" Running at Full Capacity

Actual field measurements of system voltage 1.5 miles upstream of the rock crushing operation confirmed voltage flicker is now less than ±1% -- well within the utilitys allowable parameters. The PureWave DSTATCOM practically eliminated flicker on the feeder, and delivered a cost savings of over $600,000 compared to a new distribution substation. This solution enabled the mining operation to co-exist with its neighbors on the same feeder and operate at full capacity with room for growth.

S&C Electric Company, headquartered in Chicago, IL, specializes in the development and manufacture of innovative products and services for the electric power industry. S&C's family of PureWave® Power Quality Systems have been installed at critical-process facilities worldwide to deliver reliable protection from the power quality problems that can disrupt operation. Information about S&C is available at www.sandc.com/PQ/PR.