The Most Trusted Name in Power Factor Correction and Harmonic Filtering

Successful Commissioning of Filter Banks for Vale Canada Ltd. Long Harbour Processing Plant (LHPP)

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Monday December 1, 2014

Northeast Power Systems, Inc. (NEPSI) is pleased to announce they have completed the commissioning of four 13.8 kV, indoor, 11,734 kvar, multi-tuned, metal-enclosed harmonic filter systems at Vale Canada Ltd. Long Harbour Processing Plant (LHPP). The filter system was designed and built by NEPSI to provide plant wide power factor correction and harmonic filtering.

The LHPP makes use of four 6.6 MW rectifiers in an electrolysis process to recover high quality electronickel from Vale's Voisey Bay Mine. "Filtering harmonic currents produced by these loads was a challenge as the rectifiers could operate at full power in a 12-pulse configuration, or at half capacity in a 6-pulse configuration," said Peter Steciuk, Vice President of NEPSI. These configuration changes result in two widely different harmonic spectrums, both requiring significant amounts of attenuation at their characteristic harmonic frequency's to meet IEEE 519 current and voltage distortion limits.

A rectifier operating in a 6-pulse configuration will produce significant harmonic currents at the 5th, 7th, 11th, and 13th harmonics (harmonic currents at 6n±1 where n=1,2,3,4…). The high magnitude current at the 5th and 7th harmonics requires robust 5th and 7th branch filters.

When operating in a 12-pulse configuration, the rectifier produces significant harmonic currents at the 11th, 13th, 23rd, and 25th harmonics (harmonics currents at 12n±1 where n=1,2,3,4). The absence of significant 5th and 7th harmonic currents in this operating mode shifts the filter burden from the 5th and 7th harmonics to the 11th and 13th harmonics. This shift requires more robust 11th and 13th harmonic tuned branches and nearly removes the requirement for 5th and 7th branches. The challenge was to design a cost effective harmonic filter that would not overcompensate for all operating modes, but yet have the filter capacity to attenuate the rectifier harmonics in each operating mode to IEEE 519 current and voltage distortion limits.

Vale Canada Limited (formerly Vale Inco), is a wholly owned subsidiary of the Brazilian mining company Vale, headquartered in Toronto, Ontario, Canada. The Long Harbour Processing Plant began operations in 2014 and is part of an integrated operation with Voisey Bay Mine. Nickel concentrate from Voisey Bay is shipped to Long Harbour to be processed into finished Nickel and associated Copper and Cobalt products.

NEPSI is the leading global provider of medium-voltage, metal-enclosed, conventionally switched and thyristor switched, power capacitor banks and harmonic filter banks. Founded in 1995, the New York based company has grown to be the world's market leader and most trusted name for the supply of medium-voltage metal-enclosed power factor correction and harmonic filter systems

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