Mälarenergi replaced resistors and slip-ring motors with four ACS 1000 variable speed drive systems, which improved the efficiency of the power and district heating plant. The production of electrical energy was increased by about 35 GWh per year.
This case note explains how Malarenergi AB replaced resistors and slip‑ring motors with four ABB ACS1000 variable speed drives, each rated at 1765 kW, to control district‑heating pumps. The upgrade reduced heat losses, increased electricity production by about 35 GWh per year, and lowered CO₂ emissions.
The document also details the technical data of the ACS1000 drives, the automatic differential‑pressure control achieved, and the overall benefits such as higher plant efficiency, reduced maintenance costs, and improved customer satisfaction.
| Rated power per drive | 1765 kW (2365 hp) |
|---|---|
| Voltage options | 2.3 kV, 3.3 kV, 4.0 kV, 4.16 kV (optional 6.0‑6.6 kV with step‑up transformer) |
| Motor type | Induction motor |
The plant’s electricity production increased by about 35 GWh per year.
Malarenergi has seven ACS1000 drives and one ACS6000 drive installed.
The ACS1000 supports 2.3 kV to 4.16 kV, with an optional 6.0‑6.6 kV range using a step‑up transformer.