V2 Harmonic reading double what V1 or V3 are reading PM8000

[Jeremy.Sexton]

I have a customer with a PM8000 that has an alarm for Over THD V2. V2 is reading a littel over 7.2 and the high setpoint is 5.  V1 and V3 are both reading about 3.6.  All other meters in the area show all three at about 3.2-3.8.  Is there a way to check or calibrate this input on a PM8000? Firmware is 3.1.  Meter SN is ME-2001A089-02.  

[Charles_Murison · Accepted solution]

Hello @Jeremy.Sexton ,

Calibrate, no, there is not field calibration for the PM8000 meters for any measurement. What you can do is take a manual waveform capture, export the data, then do analysis on this data and compare to the meter's readings. It is also possible if you view the waveform you may see some of the distortion on V2. 

Examples of the analysis could be Fast Fourier Transform (FFT) to get the different frequency components. 

Regards,

Charles

[Bojan]

Hello @Jeremy.Sexton ,

Check the control power wiring - if the meter power supply is taken from V3 PT, instead of a separate step down transformer, it could cause a ripple in the reference voltage.  

[Jeremy.Sexton]

Thank you.  We checked this and the meter control power is coming from a separate source.  

[Jeremy.Sexton]

Thank you.  We are working with the customer to evaluate the power quality on site.