Technical FAQs

Ask a Question

What is the difference between "THD" and "thd" on PM800 series meters

Issue:
User may notice that there are two different Total Harmonic Distortion measurements when using the PM800 modbus map

Product Line:
PM800 series meters 

Environment:
PowerLogic Metering

Resolution:

THD. Total Harmonic Distortion (THD) is a quick measure of the total distortion present in a waveform and is the ratio of harmonic content to the fundamental. It provides a general indication of the “quality” of a waveform. THD is calculated for both voltage and current. The power meter uses the following equation to calculate THD, where H is the harmonic distortion:





thd. An alternate method for calculating Total Harmonic Distortion, used widely in Europe. It considers the total harmonic current and the total rms content rather than fundamental content in the calculation. The power meter calculates thd for both voltage and current. The power meter uses the following equation to calculate THD, where H is the harmonic distortion:





 
Was this helpful?
What can we do to improve the information ?