Meeting current and voltage distortion limits in a district cooling plant

Challenges at the customer’s building

Power requirements were met by 11 diesel generating sets each of 1.6 MW at the customer’s residential complex. The main loads in the district cooling plant are centrifugal and absorption chillers, as well as pumping stations along with a sewage and water treatment plant. The loads are mainly fed by AC drives.

The short-circuit level was low at the district cooling plant, e.g., 11 KA on a 13.8 kV bus. The AC drives were a source of high harmonic currents which eventually result in higher RMS currents. Upon commissioning of the project, a number of tripping of the generation sets was observed at the facility. High harmonic distortions at the plant also resulted in the failure of one diesel-generating set. The maintenance manager also complained about frequent instrument breakdowns.

Our Merus^® Solution

Based on the loads in the facilities, Merus Power’s technical team performed a simulation and proposed 1000 A of harmonic compensation altogether. Merus Power offered 5 sets of 200 A Merus^® A-series Active Harmonic Filters.

These filters were installed in parallel to the loads on two separate busbars. They were configured to the operation mode where all the harmonics in the system up to the 50th order were being mitigated.

Results after installation

Harmonic cancellation response created by IGBT-based power electronic technology has proven to be very effective and brought elevated harmonic distortion levels below the maximum limits specified by IEEE 519 power quality standards. Individual harmonics which were quite high earlier are now negligible at the residential complex.

Tripping of the diesel generating sets has completely stopped with no further diesel generating sets failure. No further complaints about the unexplained instrument failure were given. The residential complex enjoys maximum availability and reliability and provides premium customer experience.