Improving the voltage quality
HyTEPS recently ensured good power quality during installation of two new cooling compressors in a hospital. 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
Measurements and harmonic distortion
“As continuity of supply is critical, the solution also had to be redundant. Significant 5th and 7th order harmonic distortion was seen in the current, with total harmonic current over 200A so we installed 240A active harmonic filter cabinets to reduce harmonic injection at both transformers. At the location in question, ambient temperature is generally several degrees above the recommended operational temperature, due to the presence of boilers. A water-air cooled filter system was suggested, which reduces and stabilizes the temperature of the electronics in the active harmonic filter.”
“We designed a solution using an additional PQ monitoring device to provide a complete solution for customers who demand reliability in their installation. To ensure continuity of supply and to good power quality at the transformer, a SATEC EM133 PQ meter was connected on the secondary side of the transformer. This provides regular monitoring of power consumed by the machine and the filter. Any unexpected power quality phenomenon (such as harmonics) raises an alert that can be forwarded to the Building Management System.”
“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.”
“We learnt that double checking the electrical connections with the installer and the installation responsible may save some time and effort for engineers on site. Several small challenges occurred during the commissioning phase of the active harmonic filters. These challenges helped the engineer become more confident and efficient with commissioning of such filters!”
