K factor of transformer is its ability to serve the nonlinear loads without temperature rise of transformer.
Harmonic currents generated by nonlinear loads can cause overhearing and premature failure in power transformers.
Applications of K Factor Rated Transformer
| K Factor | Transformer Loads |
|---|---|
| K 1 | Loads without solid state drives like: Motors, Heaters, Incandescent lighting, Motor Generators etc. |
| K 4 | UPS with input filter, Induction heating, AC Drive, SCR, Electric discharge light, PLC, etc |
| K 9 | DC Drives |
| K 13 | Telecom equipments, UPS without input filters. Multiwire receptacle circuits in General areas. |
| K 20 | Variable Speed Drives – VSD, Datacenters Servers, Co-Lo Servers, Multiwire receptacle circuits in Critical areas of Industries, Medical, Datacenters & office building. |
| K 30 | Multiwire receptacle circuits in Critical areas of Industries, Medical & Datacenters. |
| K 40 | Loads Producing very high Harmonics above 15th Level. |
K factor transformers are specially designed to accommodate harmonic currents and offer protection against overheating caused by harmonics. They minimize harmonic current loss and have additional thermal capacity of known limits according to its K factor rating defined in IEEE C57-110.
Higher the K-factor, greater the capacity to withstand harmonic heating effects.
| K Factor | Linear Load | Non Linear Load | 3rd Harmonic | 5th Harmonic | 7th Harmonic | 9th Harmonic |
|---|---|---|---|---|---|---|
| K 1 | 100 % | < 10 % | ||||
| K4 | 100 % | 50 % | 16.70% | 10 % | 7.10 % | 5.6 % |
| K 9 | 100 % | 100 % | ||||
| K 13 | 100 % | 100 % | 33.3 % | 20 % | 14.3 % | 11.1 % |
| K 20 | 100 % | 125% | 42 % | 25 % | 17.9 % | 13.9 % |
| K 30 | 100 % | 150 % | 50 % | 30 % | 21.4 % | 16.7 % |
| K 40 | 100 % | |||||
| K 50 |