PM8000 "invalid intervals" for power quality module

[RdM]

Hi, 

I have a PM8000 installed onsite with latest firmware uploaded. Large number of invalid intervals listed for weekly and daily intervals for IEEE519 diagram and EN50160 diagrams for Harmonics, Frequency, V-interruptions and V-unbalance. EN50160 Voltage Magnitude does not list invalid intervals. 

Can you help trouble shoot cause of an invalid interval? 

Thanks.

[Charles_Murison]

 Can you send a screenshot of Vista that includes the title bar with the diagram version?

[DanL · Accepted solution]

"invalid interval" is the (legacy?) EN50160 term for "flagging" a quantity that the signal is so far out of normal bounds that it is not marked as a "failed" interval. For example, an interval with zero voltage will have both frequency and THD marked as "invalid" for the corresponding interval, since it is likely not (just) a frequency or THD issue.

The most common problem for this symptom is incorrect meter configuration or wiring.

The meter must be configured for the correct system nominal frequency and nominal voltage.

Of course, if the meter is not properly connected to the configured voltages, intervals will be marked invalid.

Other details that help troubleshoot are:
1. "FAC1 Template" version string
2. Nominal Voltage (and actual expected system voltage)
3. PT Prim : PT Sec (if applicable: how many PTs and how are they wired)

4. Volts mode (and which wiring diagram does this installation correspond to)
5. Nominal Frequency (and expected system frequency)

[RdM]

Thank you. In our application the meter was correctly configured. 

Your response helped us diagnose that the system being monitored had negligible load while connected pumps weren't running. Therefore, these periods were counted as invalid and reporting was correct.