Many companies in the water and waste-water sector use Variable Frequency Drives (VFDs) to efficiently control the electrical power needed to run motors, pumps, and other mechanical systems. While the VFDs provide greater control over the output, they also have a tendency to introduce harmful harmonic distortion into your electrical system. When this occurs, you can experience overheating of components, equipment malfunction, nuisance tripping of circuit breakers, and inaccurate measurements on sensors.
In the water industry, it is quite common to see the use of multi-pulse drives to reduce harmonic distortion. However, there are better options. MTE has worked with a number of companies in the water industry to control harmonics using a six-pulse drive with the Matrix® AP passive harmonic filter. In addition to helping them meet IEEE-519, standards, the solution is smaller, more efficient and more cost effective over other low harmonic drive solutions.
The 6-Pulse drive with Matrix AP harmonic filter outperformed the 18-pulse drive in the following important areas*:
Power loss: 40% – 73% depending on the size of the VFD and the component manufacturer.
Overall efficiency: 0.5% more efficient (99.0% vs. 98.5%).
Harmonic performance under balanced line conditions: 1-2% better THID performance for loads 25-75% and equal performance for loads greater than 75%.
Harmonic performance under line imbalance conditions: Significantly better performance. For example, under 3% line imbalance, performance was 32.5% better (17.5% vs 50%
THID) at 25% load and 13% better (12% vs 25% THID) at 50% load.
Power Factor: Better to equal performance for loads 50-100%.
*These findings are based on the performance of a 100 HP 18-pulse drive with the performance of a standard 100 HP 6-pulse drive equipped with a 128 amp Matrix AP harmonic filter.