The short-circuit generator system at Ratingen is used to supply heavy duty currents and high power for testing of the ABB circuit breakers, switchgear, insulators, and transformers produced there. The generator, which can supply up to 80,000 amperes with 11,000 volts for short periods, is operated by a prime mover that was previously cooled by three unregulated fans. The fan motors were powered up via the star-delta switch and once they were turned on, they always were running at full load, thereby wasting a lot of energy.
Matching fan speeds to real needs give considerable savings
To improve fan control and eliminate much of the energy waste, three ABB ACS580 drives were fitted on the fan motors last year. Since then, they have been efficiently controlling the prime mover fans in the test lab, delivering many benefits.
"Thanks to the new drives, the speed of the fans is now adjusted according to the real-time needs, making their operation much more energy- and cost-efficient," explains ABB Ratingen test engineer Frank Idaszek, who supervises the test facility and is also responsible for measurement and control technology in the plant.
After Ratingen had decided to do the modification, the ACS580 drives were promptly delivered, and set-up was quick, says Idaszek. The entire project including laying of new cables and integration into the ABB 800xA control system was completed within two weeks.
Now the fans are monitored and controlled by the drives in real time, with the fan speeds based on measurement of the temperature at the bearings and in the windings of the prime mover machine, with the help of six temperature sensors. If temperatures in the bearings and windings are too high the fans speed up, and when temperatures return to normal the fan speeds reduce or stop entirely.
Good experience with ABB drives
ABB's general purpose drives have been used on other applications in the test facility for a long time. For example, the bearings of the prime mover are cooled not only with air, but also with oil that is moved by a pump that is regulated by two ACS580 drives as well.
Regarding drive technology, Idaszek attaches great importance to energy-efficient solutions that also provide both high availability and a long service life. And he has had very good experience with ABB equipment. "I work for ABB but at the test facility we can select whichever equipment supplier that we feel best serves our needs. The fast delivery times and strong support from the responsible ABB unit are real differentiators versus the products of other market suppliers," he states.
Fast payback and big benefits in noise and CO2 footprint too
The main advantage of the ACS580 drives is the significant operating cost savings due to lower energy consumption. As an example of the fast payback, the purchase of the two ACS580s used on the oil pump paid the cost back after just one year. In addition, the drives’ smoother start and stop functions, and the lower pump speeds used, also extend the lifetimes of the motors. In addition, another small but important advantage Frank Idaszek has noticed is that the oil pump of the prime mover has been running much quieter since the changeover to the ACS580 drives.
Furthermore, on the recommendation of the ABB's test engineer, the load curve of the drive-controlled fan systems was changed from constant to square. As a result, the system consumes up to 6% less energy in partial-load operation. Since the Ratingen site aims to be CO2-neutral by 2025, this extra energy savings is another important contribution made by the ABB drives.
ABB in Ratingen
At ABB’s Ratingen facility near Düsseldorf in North Rhine-Westphalia, Germany, more than 1,000 ABB employees develop, manufacture and test medium-voltage products and solutions. This includes system solutions such as medium-voltage switchgear and associated components. In addition to research and development, production, service, sales and an in-house test lab, ABB's global center for vacuum technology is also located at the site.
