ADF Secure Food Production by Mitigating Harmonics
Processes with high automatization often contain VFDs, which cause harmonics in the power supply. This can affect machineries and could cause downtime in production lines, as was the case at REWE in Dortmund.
REWE Dortmund Großhandel eG is a federation of over 300 independent retail dealer and supplies approx. 540 grocery stores. The center is the 100.000 m² warehouse and distribution center in Dortmund-Asseln with affiliated butcher. After a fire destroyed the butcher in 2009, it had been rebuilt and expanded in 2011 into an 18.000 m² large butcher shop. Since the end of 2011, REWE produces 250 tons of meat for the grocery stores and up to 25 tons of sausages every day. The new butcher shop contains state of the art logistics and meat processing systems.
The new meat cutter and the included VFDs created the typical current harmonics of a six-pulse-converter (5th, 7th, 11th, 13th, etc). These harmonics resulted in commutation notches in the voltage which influenced the whole process. It caused disturbances in the light and blackouts. Furthermore it influenced the sausage stuffing and caused long production stops, which disturbed the process flow. Occasionally up to 50 % of the employees had to be sent home for the day due to disturbances in the process.
Solution – ADF Active Dynamic Filter with Harmonics Compensation
REWE decided to use a Comsys ADF Active Dynamic Filter to eliminate the problems in the power supply. The installed system consists of one ADP P300-300/480 with a capacity of 300 A harmonics compensation to provide the needed harmonic power for the meat cutter.
- High harmonic current distortion
- Large disturbance of production
- Low harmonic current distortion
- No disturbance of production
After the installation and short commissioning, all disturbing harmonics were canceled and the commutation notches disappeared. For the first time it was possible to start all meat cutters at the same time, without any effect on the light or the sausage stuffing process.