When electrical equipment runs poorly or erratically without any seemingly good explanation, the problem could be due to harmonics. Typical problems associated with harmonics include overheating of DOL (direct-on-line) motors and other equipment, flickering lights (including UV lights in the water treatment process), false readings of water flow meters and instrumentation, generators and circuit breakers that trip, fuses that blow, capacitors that fail, or even flow interruptions. In some cases, there might even be a risk of incurring a fine from the power company due to excessive consumption of reactive power in the power network.
When using variable speed drives to control the speed and torque of a motor driving a water application such as a pump, compressor or mixer, the traditional way of managing harmonics has been to install external filters or to use multi-pulse transformers. This reduces the incidence of harmonics, resulting in less disturbance. It is also common to over-dimension the transformer, generator, power cable or fuse used to ensure continuous operation of the water application. However, difficulties with this set-up include less space for installing the equipment, as there are several wearing parts and unnecessary costs when investing in over-dimensioned equipment.
Tackling harmonics
The water-dedicated ACQ580 ultra-low harmonic VSD produces exceptionally low levels of harmonics (even below 3% THDi), helping to keep water sector power networks clean, stable and IEEE519 compliant. The VSD eliminates the need for installing external filters or multi-pulse transformers. It also offers several built-in functionalities for ensuring optimal pumping of water or wastewater. Using an ACQ580 VSD can lower the energy bill, reduce wear and tear of the equipment and save time for operating the application. The VSD can be accessed remotely for condition monitoring, and is supported locally by ABB’s channel partner network and global services.