Tips when making K-factor measurements:

• Make your measurements in a “normal” steady-state waveform cycle, before or after a waveform transient.
• Periodic capture waveforms are preferred for K-factor calculation.
• Pay attention to the amount of current (RMS value) that is involved in large K-factor measurements.  If the current is low compared to the 60 Hz transformer rating, the K-factor may not be an issue.
• Infrequent and short- lived mild surges and waveform anomalies rarely adds much to transformer heating.  When analyzing RMS current for transformer heating 5 or even 15 minute averages are appropriate.

Proactive monitoring of transformer load should be done to detect excessive heating that eventually causes the transformer to fail.  If a customer is planning a large expansion or load increase, before and after measurements should be performed.

Usually when a transformer fails, it happens very suddenly, interrupting customers and requiring immediate attention. A proactive approach is always better than having to put out fires.