Selecting Harmonics Transformers vs. K-Factor

The first signs of the incompatibility between conventional building power distribution systems and personal computers became obvious in the mid-1980s as more and more personal computers appeared in the workplace. One decade later, personal computers, monitors, powerful workstations, laser printers, and other modern electronic office equipment typically form a large portion of the electrical load in a building. Because these loads are very non-linear, their load currents are rich in harmonics, causing problems for both the power distribution system and for the electronic equipment itself. The electrical industry's first response to these four problems was to double the ampacity (current carrying capacity) of the neutral conductors so that they would not burn-up. This is becoming a standard design practice in office buildings. The second response was to beef-up the distribution transformer so that it would not fail due to the higher heat losses caused by the harmonic currents flowing through it. These transformers are now known as k-factor rated transformers.