Speedy AC drive retrofit for Linz Strom

AUSTRIA: Is modern power generation more about sustainability or delivering reliably? Yes and yes, both are essential. That’s why the Austrian energy provider Linz Strom Gas Wärme GmbH focuses on keeping its power plant operations efficient and environmentally friendly.

Linz Strom operates seven power plants optimized for reliable electricity availability. The primary energy sources gas, biomass, oil (reserve fuel), residues and sewage sludge are converted into energy in the form of electricity and district heating, to power local businesses and homes. One of the Linz Strom plants needed to replace three ageing AC variable speed drives used in control of intermediate pumps. These drives, which were not of Danfoss manufacture, were 250 kW air-cooled types and had reached the end of their reliable service lives.

Harmonic mitigation, time and space limits

Special requirements were that the new drives had to fit into the space made available by removing the old units. In addition, effective harmonic mitigation was required to protect the pumps. Furthermore, the complete replacement process, including the removal of the old drives, must be completed within two days. For long term peace of mind, Linz Strom also required a maintenance agreement to ensure ongoing reliable operation.

After evaluating multiple suppliers, Linz Strom Gas Wärme GmbH finally entrusted the project to Danfoss Drives and Sprecher Automation, an approved Danfoss Drives system builder. The decision was based on Linz Strom’s longstanding relationship with Danfoss, which spans more than 20 years, and the availability of 24/7 support for the new drives, along with the excellent performance, reliability and value for money offered by Danfoss products.

Retrofit completed in less than 2 days

Linz Strom chose to adopt the DrivePro® Retrofit service to streamline the replacement process. VACON® NXP Air Cooled AC drives were selected as the most suitable replacements, thanks to their compact construction, high efficiency, and exceptional reliability.

To protect the pump motors, which were not replaced, the new AC drives were fitted with common-mode core kits. dU/dt filters and RFI filters were also installed. Danfoss supplied the new AC drives on schedule, while Sprecher Automation dismounted the old units and installed the replacements along with other associated electrical work.

The project was completed in under two days, to minimize disruption to operations. To complement its new VACON® NXP Air Cooled AC drives, Linz Strom also purchased a DrivePro® Extended Warranty package. This service provides 24/7 on-site support for 36 months, together with guaranteed availability of spare parts.

Low energy expenditure

The new AC drives from Danfoss are now in regular service and are fully living up to expectations. They are providing Linz Strom with greatly improved reliability and, thanks to their exceptional efficiency, a significant reduction in energy expenditure.

The DrivePro® services proved their worth in this important project, ensuring that challenging requirements for fast completion were met and that the customer has complete peace of mind for the future.

“We chose Danfoss drives due to their dependability, and not least the availability of 24/7 support which we have appreciated over the years” says Josef Aichinger, Head of Maintenance Power Plants at Linz Strom.