CALCULATION OF TOTAL HARMONIC VOLTAGE DISTORTION
The following calculator computes the total harmonic voltage distortion, Peak Voltage, RMS Voltage, and Crest Factor based on individual harmonic voltage distortion values between the 1st and the 50th harmonic. Input the fundamental voltage and individual harmonic voltages to compute results also to view a waveform plot based on the input values. The waveform plot assumes all phase angles for individual voltage distortion values to be zero degrees (in phase with the fundamental voltage).
When inputting the data, be sure to use consistent units of Volts, KV, or Per Unit Volts. Additionally, be consistent with either line-to-line values or line-to-neutral values.
Of Interest...
Total Harmonic Voltage Distortion or THD, of a signal is a measurement of the harmonic distortion present and is defined as the ratio of the sum of the power of all harmonic components to the power of the fundamental frequency. THD is used to characterize the power quality of electric power systems. Distortion factor is a closely related term and sometimes used as a substitute term.
IEEE 519, "Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems" provides suggested limits for harmonic voltage distortion as shown in Table 10.4 below. A 5% voltage distortion is barely noticeable on a voltage waveform plot but can result in power quality issues. This is especially true in an environment where resonance may exist at the frequency of the individual harmonic voltage that contributes to the total harmonic voltage distortion.
Harmonic Filters sold by NEPSI can be used to mitigate and reduce voltage distortion on utility and industrial power systems.
Crests Factor is a measure of a waveform showing the ratio of the peak value to the RMS value. A crest factor of 1.0 indicates no peaks, such as the case with DC Voltage. A voltage waveform with 0% THD will have a crest factor equal to 1.414. Crest Factors greater than 1.414 usually indicates the presence of harmonic distortion.
Calculator
Known variables: Fundamental Frequency Voltage, Harmonic Voltages
