Improving welding quality by reducing flicker and load unbalance with real-time reactive power compensation

Challenges in the customer’s metallurgical plant

Welding is an important process in the customer’s metallurgical plant. The welding cycle length was approximately 120 ms. The demand for higher current for such a short period of time resulted in a power quality challenge commonly termed as flicker. As the distribution board was also supplying other customers in the industrial area, other plants were affected by flicker as well.

Apart from unpleasant human experience, the flicker also impacted sensitive equipment such as PLCs and computers. A detailed power quality analysis not only confirmed high flicker values but also revealed load unbalance.

Our Merus^® Solution

Low-voltage Merus^® Active Harmonic Filters were installed parallel to the loads. Excellent flicker reduction and load balance were key criteria for the customer’s preference for Merus^® Active Harmonic Filters over conventional technologies. While conventional technologies tend to respond too slowly to fast and instant reactive power compensation requirements, Merus^® Active Harmonic Filters respond in less than 1 millisecond.

Merus^® Active Harmonic Filters are configurable according to various customer requirements. Configuration is simple and only a few clicks away, thanks to the modern touchscreen Human Machine Interface (HMI).

Results after installation

The customer’s metallurgical plant is now running smoothly without any sign of flicker, thanks to the effective and fast response time of Merus^® Active Harmonic Filters. Flicker values are well below 1 and are now in full compliance with parameters defined by global standards such as IEC 61000-2-2 and EN 50160.

Merus^® Active Harmonic Filters not only reduced flicker but also balanced currents in the 3-phase system. Sensitive equipment in the plant is now protected against any future damages and the plant runs at optimum efficiency.