Voltage Imbalance Calculation Method with AVG/MIN/MAX Data
Voltage Imbalance Calculation Method with AVG/MIN/MAX Data
(OP)
Good Morning
I have a question on how to calculate voltage imbalance.
The data that have contains AVERAGE MINIMUM and MAXIMUM values for each of three phases, with records recorded one time per second.
I know the voltage imbalance percentage formula, and repeat it here:
Formula stating Voltage unbalance=100 x Max. deviation from average voltage/Average voltage
For example, if measured line voltages were 455, 460, and 492, the average would be 469 volts (455 + 460 + 492 = 1407 / 3 = 469). The maximum deviation from that average is 23 volts (492 - 469 = 23). To find the voltage unbalance, solve the equation for the average voltage and the maximum
voltage deviation: Formula stating Voltage unbalance=100 x (23/469) = 4.9%
My question is which voltage values should be used in the calculation.
I think that I should use the AVERAGE of all (AVGab +AVGbc + AVGca)/3, and the maximum deviation being the largest of the AVERAGE from each phase AVG. correct?
I have a question on how to calculate voltage imbalance.
The data that have contains AVERAGE MINIMUM and MAXIMUM values for each of three phases, with records recorded one time per second.
I know the voltage imbalance percentage formula, and repeat it here:
Formula stating Voltage unbalance=100 x Max. deviation from average voltage/Average voltage
For example, if measured line voltages were 455, 460, and 492, the average would be 469 volts (455 + 460 + 492 = 1407 / 3 = 469). The maximum deviation from that average is 23 volts (492 - 469 = 23). To find the voltage unbalance, solve the equation for the average voltage and the maximum
voltage deviation: Formula stating Voltage unbalance=100 x (23/469) = 4.9%
My question is which voltage values should be used in the calculation.
I think that I should use the AVERAGE of all (AVGab +AVGbc + AVGca)/3, and the maximum deviation being the largest of the AVERAGE from each phase AVG. correct?






RE: Voltage Imbalance Calculation Method with AVG/MIN/MAX Data
RE: Voltage Imbalance Calculation Method with AVG/MIN/MAX Data
Assuming the "Average" values represent the average rms voltage over the one second interval, that's what I would use, but even that might be misleading.
Voltage imbalance is a long-term problem, especially for motors. Short periods (a few seconds) of voltage imbalance are not generally a major concern as long the the voltage transient is not too severe and doesn't occur too frequently.