My device can provide reading of Line to neutral values through Modbus , I'm requested to provide Line to Line readings which is not available in our Modbus table for the device. Is it possible to get Line to line value (U12, U23, U31) from Line to neutral RMS reading (U1n, U2n, U3n)



If you can rely on the three phase voltages being 120 degrees apart then you can vectorially add two phase voltages to yield a line voltage: -

enter image description here

The above shows three phase voltages VR, VB and VY. these vectorially add to produce the line voltages shown.

Clearly, if the phase angles are not exactly 120 degrees apart then there is some error in this technique. You cannot tell what the phase angles are from the magnitudes of phase voltages so unless there is some phase data that can be used, I think this is all you can achieve.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.