Ensuring power quality and reliability at largest provincial hospital

The energy transition is making electrical power indispensable and quality of electricity supply is of the utmost importance. In industrial installations, for example, power quality ensures optimal usage of power consumed, and reduces electrical component aging. In certain electrical installations, good power quality can even save lives. Hospitals require minimal electrical network pollution to ensure electrical installation reliability. With large numbers of patients being treated, continuous supply of power to medical equipment may not be compromised. Ensuring good power quality minimises the possibility of a power quality event occurring and makes hospital power supply reliable.

2 x 240A – Size of the suggested active harmonic filter 48% and 25% - Current harmonics in the 5th and 7th order measured before solution EM133– PQ meter used for monitoring for extra layer of information

The Challenge

HyTEPS was approached to ensure good power quality during installation of two new cooling compressors at the largest hospital in one of the Netherlands’ provinces. Cooling consumes significant electrical power (over 500kW). Use of switching semiconductors meant the possibility of harmonic injection was quite high. In addition, with higher harmonic power drawn, transformers are burdened with a higher load. To prevent unexpected interactions with the electrical network and reduce the load on the transformer, HyTEPS was asked to perform measurements and recommend a solution. At the location in question, ambient temperature is generally several degrees above the recommended operational temperature, due to the presence of boilers. As continuity of supply is critical, the solution also had to be redundant.

Goals

  • Perform measurements at the electrical installation and assess power quality.
  • Provide a solution to ensure new electrical machines operate without introducing power quality-related risks.
  • Ensure the solution is comprehensive and provides feedback in case of unexpected measurements.

Solution

HyTEPS engineered an ingenious solution. “After performing measurements for the cooling compressors, significant 5th and 7th order harmonic distortion was seen in the current, with total harmonic current over 200A,” explains Joost Giesbers, Electrical Engineer, HyTEPS. “HyTEPS proposed installing a 240A active harmonic filter cabinet to reduce harmonic injection at the transformer. The solution was replicated for both cooling machines. As the room’s ambient temperature was higher than optimal, a water-air cooled filter system was suggested, which reduces and stabilizes the temperature of the electronics in the active harmonic filter.”

To ensure continuity of supply and to good power quality at the transformer, a SATEC EM133 meter was connected on the secondary side of the transformer. This provides regular monitoring of the energy consumption of the machine and improves power quality achieved by the filter. Any unexpected power quality phenomenon (such as harmonics) raises an alert that can be forwarded to the Building Management System.

 

Results

Joost: “With our help, the active harmonic filter was successfully commissioned as a solution for the high harmonic content in the current injected by the load.  Since the installation and commissioning over a year ago, we haven’t heard of any issues. With a water-air cooled active harmonic filter, less maintenance is required, as there are no external facing fans that might collect dust. In addition, the cooler and stable temperature helps the fans run longer. A float sensor was also provided at the cabinet floor to detect any water leakage and raise an alarm.”

 

“The customer and installer were extremely pleased with the work provided by HyTEPS. By ensuring efficient communication between the customer, the installer and the HyTEPS engineer, the customer has only had good experiences with HyTEPS!”
Joost Giesbers, Electrical Engineer, HyTEPS