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Power Quality Solutions for Water/Wastewater

MTE Corporation helps many water/wastewater treatment facilities by delivering a wide array of optimized, power quality solutions. These facilities require carefully controlled flow rates and chemical dosing to ensure safe processing of fresh and grey water, respectively. Water/wastewater facilities and pumping stations use a variety of pumps in their operations, that are driven by variable frequency drives (VFDs), to propel the water through the many stages of purification along the way.

Water treatment plants use pumps to pass fresh water through a filtration process that reduces sediment and purifies the water to ensure safe public consumption.

Wastewater, or sewage treatment plants, use pumps to transfer water between clarifying treatment tanks to accurately apply additives, bacteria, and chemicals. Once completed, the water is reintroduced into the environment.

Pumping stations play a critical role in managing flow across the water ecosystem – from the source to treatment plants, for fresh water distribution, and to deliver grey water to wastewater treatment sites.

Power Quality Challenges for Water/Wastewater Treatment Facilities

VFDs can generate harmful harmonic distortion that, when left unchecked result in equipment damage, costly downtime, nuisance tripping, and reduced efficiency. Power quality issues in water/wastewater applications can lead to hazardous operating conditions resulting in critical disruptions to business and municipalities.

For decades, 18-pulse VFDs have been used to reduce harmonic distortion throughout the water industry. However, as the infrastructure inside these facilities begins to age, the cost to repair or replace these multi-pulse drives due to unscheduled downtime and equipment failures result in extensive losses in revenue and productivity.  Premature motor failure and transformer damage, as well as sensor signal interference are also a result of unwanted harmonics caused by VFDs. MTE solutions provide peace of mind when it comes to the many power quality challenges water/wastewater treatment facilities face.

  • Cost of Downtime – The majority of shutdowns are unplanned and result in significant monetary losses.
  • Assurance of Supply – Safe and continuous water supply is critical to municipalities, hospitals, and businesses.
  • Safety and Welfare – Over 75,000 sanitary sewer overflow events occur in the US each year creating financial and human risk.
  • Sensor Interference – Unmitigated harmonics and noise can corrupt sensitive signals required for proper operation.
  • Multiple Non-Linear Loads – Non-linear loads include VFDs, uninterrupted power supplies (UPS), ozone generators, and UV lights.
  • Motor Protection – Differential and common mode voltage and currents lead to cable damage, premature motor failure, and pitting, frosting, and fluting of the bearings.

Matrix AP outperforms 18-Pulse Drives

While multi-pulse drives have been the standard, 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.

A 6-Pulse drive with Matrix AP harmonic filter outperforms an 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 in nominal conditions: 1-2% better THID performance for 25% – 75% loads and equal performance for loads greater than 75%.
  • Superior performance under line imbalance conditions: At 3% line imbalance the Matrix AP is over 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.

MTE Featured Water/Wastewater Solutions

Whether you’re looking for IEEE-519 utility compliance or you need to protect your motors from costly downtime, MTE’s broad range of solutions for both the line and load side of VFDs help mitigate, and in some cases eliminate, the majority of the power quality issues that arise.

Line Side Solutions

Load Side Solutions