I am looking for some standard power quality indices. By the PQ index, I mean the numerical value which gives an insight into the quality of the power supply waveform being monitored.
For example, you have a pure supply waveform the index is 10 (out of 10) and for a waveform with some harmonic disturbances, the index would be 7 (out of 10), the index being provided on some valid calculations or assumptions.
If you can share any useful references on the same, it would be really helpful. Thanks in advance.
Dear Sobin,
The standard power quality measure in the power system is Total Harmonic Distortion (THD) of voltage or current in %. It compares the pure sinusoidal waveform with the waveform that contain harmonics. 0% THD means that the waveform is totally matched with the pure waveform and 100% means totally mismatched. Several IEEE and IEC standards indicates the power quality in the form of THD.
Conference Paper Harmonic and Interharmonic Measurement According to IEEE 519...
Conference Paper Update on IEC 61000-3-6: Harmonic emission limits for custom...
Hope these two articles will help
Standard power quality indices for various parameters like frequency are defined by the respective utilities depending on their operating conditions. However various standards also specify the limits. As for as systems with converters ( renewable energy sources like solar connected to grid) harmonics content plays a role. There I agree with Prof. Alaq Hussain.
Voltage and current quality should be good. Less THD value in voltage and current is the indication of good quality voltage and current. As per IEEE Std. THD in voltage and current should be less than 5%.
To assess the quality of the output voltage of AC voltage sources, the THD coefficient is used. However, such an assessment is not complete. Distortion of the form leads to the appearance of reactive power. To evaluate such power, the approaches of Frieze and Budeani are usually used.
IEC TS 62749:Assessment of power quality-characteristics of electricity supplied by public networks might provide you information on this matter.
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