August 12, 2002

Steel Fabricator Keeps Rolling Thanks to PureWave AVC™.

Background

A steel fabrication facility in east Texas specializes in the manufacture of steel pipe for the petroleum industry. Several years ago, the facility replaced its aging motor-generator sets with variable-speed drive motors.

As large ingots were reduced in size, the instantaneous load on these motors created significant increases in the immediate and short-term demand for reactive power. Peak reactive power demand was close to 11 MVAR.

The primary source of the problem was the “2Hi” rolling mill, where most of the size reduction was performed on the ingot. When in operation, this mill created voltage sags of up to 8% on the 13.8-kV East Mill Motor Room bus . . . severe enough to trip off 480-V motor loads fed from this bus, and causing poor overall power factor for the entire facility.

What Did They Do?

The facility procured a 5000-kVAR PureWave AVC Adaptive VAR Compensator. The device was connected to the 13.8-kV East Mill Motor Room bus, to provide reactive power as close as possible to the primary source of the demand, the “2Hi” rolling mill.

Results

The PureWave AVC was installed and commissioned in January 2000, and has performed extremely well, exceeding all customer acceptance criteria. Voltage variation on the 13.8-kV bus is now maintained within ±3.2% of nominal, and power factor is now typically above 92%. Total voltage and current harmonic distortion are now less than 10% and 5%, respectively. The aforementioned problems with mill equipment have all been eliminated.

The facility is now evaluating additional reactive compensation to further improve performance.

Single-line diagram of electrical distribution system with
PureWave AVC Adaptive VAR Compensator installed.