Hi,
we have 2 PMUs with openHistorian successfully fetching data from openPDC.
In stream files there is a configuration frame where it says how certain values are scaled.
I’m asked to retrieve this reading factor which is used to multiply the values obtained through the stream to get the actual values.
Where exactly can I get this information in openPDC?
Thanks,
George
Hi George,
Are you asking about possible scaling factors used within the IEEE C37.118 stream?
Thanks,
Ritchie
Yes,
based on PMU Send which implements a server that sends synchrophasor data on request, scale for analog signal is simply a multiplier. User just specifies the value by which the analog value is multiplied.
I’ve mange to find it.
Information is available for all phasors, among other information, in dbo.Measurement table in openPDC and openHistorian database.
Looks something like this when you filter it by PMU-name in “Description” tab.
Adders and Multipliers are 0 and 1 in this case but they could have any other information that would actually impact calculations.
Regards,
George
Hi George,
These are scaling factors that can be applied by the openPDC to manually apply linear adjustments to incoming data. These are not part of the original IEEE C37.118 configuration or data stream.
Sometimes device measurements can be off by a specific amount, like srqt(3), so these adjustments can be made on individual measurements in the openPDC itself as data comes into the system.
Thanks,
Ritchie
Hi Ritchie,
thank you for your response.
I’m guessing that configuration frame than should hold information about the factor that you’re mentioning ("… can be off by a specific amount, like srqt(3)…").
Do you have any idea where to find this “amount” in openPDC or openHistorian ?
Thanks,
George
In the openPDC or openHistorian UI Manager application (not the web app), go to Metadata > Measurements from the main menu. Search for the measurement in question, check the Adder and/or Multiplier fields.
Thanks,
Ritchie
