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Sending Calculated measurements in an output

Nov 22, 2013 at 6:22 PM
Hello, is it possible to send calculated measurements in a C37.118 Output? I've tried associating the measurements to a device, adding the device to the output stream (including anaolgs), adding the measurements to the output stream. Nothing seems to work. Any help would be appreciated.

Nov 22, 2013 at 6:45 PM
Yes, but there is a trick to it, though.

I have not had success sending 'CalculatedMeasurement' measurements in the C37.118 stream (however, I will defer to Ritchie or Stephen on this) because the protocol only supports, Phasors, Digitals, Analogs, StatusFlags, Freqeuncy, and Frequency Delta. So, if your measurement is originally modeled as one of those types, it can be picked up by a C37.118 stream. Additionaly, your measurements have to belong to a PMU device. You cannot add measurements directly to a C37.118 outputstream. So here is what to do:
  1. Create a virtual PMU device to send your calculated values to. There is documentation on the website for this.
  2. Add Phasors or any other of the above listed measurements to that device. These are your destination measurements. You will send your calculated values to these measurements. (think of them as placeholders). Note that if you have a calculated value that doesn't seem supported, use the Analog data type.
  3. for your device to speak C37.118 properly it will need a Frequency measurement, a Frequency Delta measurement, and a Status Flag measurement preferably with legitimate values i.e (60, 0, 0).
  4. Map your calculated values to the virtual PMU device measurements by making those measurements output measurements in the connection string of your action adapter.
  5. Add the virtual device to the output stream making sure to select 'Add Digitals' or 'Add Analogs' based on what measurements you are calculating.
Then you should be able to send those values via C37.118.

Good luck,
Nov 22, 2013 at 7:53 PM
Edited Nov 22, 2013 at 10:20 PM
It seems like allowing the ability to add a calculated measurement to an actual device rather than a virtual device would make this process a lot less complicated. So, I'm following this tutorial to create the virtual device: It looks like what it is doing is creating a virtual device, creating virtual phasors, virtual digitals and virtual analogs and the adding the actual (calculated or otherwise) measurements to the virtual device. It then sounds like you need to map the actual measurements to the virtual phasors, analogs and digitals by modifying "the Signal Reference of the measurements you added in order to associate the measurements with your virtual output device." So does this mean that I need to change the signal references of my actual measurements to the virtual signal references of the device? If I'm adding an arbitrary frequency measurement to this virtual device so that it complies with C37-118, then what happens to the mapping of that signal to the actual device? Won't changing the signal reference to the virtual device disconnect that measurement from it's actual device?

EDIT: So it seems like you can add calculated measurements to existing devices. You just have to make sure that the signal type is set to analog value and that the Signal Reference has an "-AV" suffix (openPDC manager will crash if this is not the case). It seems like the latter requirement may be a bug as it should be pulling the "AV" suffix definition from the signalType table so that the references can be named whatever the user may want. I'm still working on getting this to work with a virtual device however, it is unclear how to map actual calculated measurements to virtual analog signals.

Lastly, the C37.118 Names of the analog channels seem to be arbitrarily named, (in my case PMUNAME:A0 - PMUNAME:A8) and do not necessarily correlate to the Signal references (in my case SignalReferenceName-AV1 - SignalReferenceName-AV9). Is there any way to tell which C37.118 Channel label correlates to which OpenPDC Signal reference?
Nov 22, 2013 at 9:54 PM
Edited Nov 22, 2013 at 10:20 PM
Hi Dave,

You can, in fact, add a calculated measurement to an existing device. You have the option of associating that measurement with the input device itself, or associating it with the output device as described on the link you provided for virtual devices. Consider the following example.

Using the sample data set, I would like to calculate PPA:6 plus PPA:8 (sum of the voltage phase angles) to produce a third measurement called PPA:68. I would then like to add PPA:68 to the output stream as part of SHELBY's configuration.

Option 1: Add the measurement to SHELBY's configuration.

Note: In creating PPA:68, its Measurement Type is Analog Value, its Device is SHELBY, and its signal reference is SHELBY-AV1. This option is possible because the protocol parser will ignore PPA:68 since there is no such measurement coming directly from SHELBY.
  1. In the openPDC Manager, go to "Outputs > Concentrator Output Streams".
  2. Click the "Device Wizard" link for the output stream that contains SHELBY.
  3. Check the box next to SHELBY and click the "Delete Selected" button.
  4. Click the "Add More Devices" button.
  5. Select SHELBY, and make sure the "Add Analogs" and "Add Digitals" checkboxes are selected.
  6. Click the "Add Selected" button.
  7. Go back to "Outputs > Concentrator Output Streams" and click the "Initialize" button.
  8. When prompted whether to initialize the output stream, click "Yes".
Option 2: Add the measurement to your output stream configuration.

Note: In this case, PPA:68 can be any Measurement Type and its signal reference can be anything you like. It also does not need to be associated with SHELBY. In this test case, I used Calculated Value and SHELBY-CV1.
  1. In the openPDC Manager, go to "Outputs > Concentrator Output Streams".
  2. Click the "Devices" link for the output stream that contains SHELBY.
  3. Click the "Analogs" link for the SHELBY output device.
  4. Add an analog value to represent our calculated value in the output stream. Label can be anything (SHELBY:A0 to be consistent with option 1).
  5. Go back to "Outputs > Concentrator Output Streams".
  6. Click the "Measurements" link for the output stream that contains SHELBY.
  7. Click on the giant link labeled "Click here to add source measurements to the output stream".
  8. Check the box to the left of PPA:68 and click the "Add Selected" button.
  9. Locate PPA:68 in the grid below the giant link. Select it and change its signal reference to SHELBY-AV1.
  10. Go back to "Outputs > Concentrator Output Streams" and click the "Initialize" button.
  11. When prompted whether to initialize the output stream, click "Yes".
In both cases, you should be able to use the PMU Connection Tester to connect to your output stream and to see that your calculated value has made it into the stream.

Marked as answer by ritchiecarroll on 11/25/2013 at 7:48 AM