Active harmonic filtering improves reliability at a water treatment plant

A water treatment plant in Galati, Romania, reduced total harmonic current distortion (THDi) from approximately 32.6% to 4.8% with Merus^® A2 Active Harmonic Filters, improving power quality and supporting reliable plant operation.

Challenges in the customer’s water treatment plant

The water treatment plant uses 6-pulse Variable Frequency Drives (VFDs) to control its processes. While VFDs provide efficient and flexible motor control, they are non-linear loads that can introduce harmonic currents into the electrical network.

Measurements at the plant revealed significant harmonic distortion, with the 5^th and 7^th harmonic components causing the greatest impact. High harmonic distortion can increase stress on electrical equipment, interfere with sensitive devices, and increase the risk of operational disturbances.

The plant therefore needed an effective harmonic mitigation solution to improve power quality and meet local harmonic distortion requirements.

Our Merus^® Solution

Four 200 A Merus^® A2 Active Harmonic Filter modules were installed in parallel with the load, providing a total compensation capacity of 800 A. The system was installed with the support of a local integrator.

Merus^® A2 continuously monitor the electrical network and dynamically compensate harmonic currents. In this installation, the filtering capacity was optimized between the dominant 5^th and 7^th harmonic components to achieve effective harmonic mitigation.

The modular solution also provides flexibility for demanding applications where load conditions and harmonic levels can vary during operation.

Results after installation

After the Merus^® A2 Active Harmonic Filters were commissioned, total harmonic current distortion was reduced from approximately 32.6% to 4.8%.

The lowest distortion level was achieved by optimizing the filtering capacity between the dominant 5^th and 7^th harmonic components. As a result, harmonic distortion was brought down to acceptable levels, and the overall power quality of the plant was significantly improved.

Improved power quality reduces electrical stress on sensitive equipment and supports more reliable operation of the water treatment process. For the customer, this means a lower risk of unplanned downtime and maintenance while supporting a longer lifetime for electrical equipment.