Three-Phase V-I Measurement with 4 wires

There's a block from the Simscape library called Three-Phase V-I Measurement (picture attached). I would like to use it with a three-phase system that has 4 wires (ABCN, 3 phases and 1 neutral). How should I go about this?

I suppose the best way is to create a custom block. I was reading this documentation, but I was wondering if there's some type of S-function written for the block that alredy exists so I can understand how it works better and I write my own code for my modified block.

Answer 1

[Sumukh]

Hi M.,

The “Three-Phase VI Measurement” block available in Simscape Specialized Power System (SPS) library, is for measurement of voltage and currents in three-phase networks. An option is available in the block parameters, where either “phase-to-phase" or “phase-to-ground" voltage can be measured. You can refer to this documentation to know more about configuring the “Three-Phase VI Measurement” block:

https://www.mathworks.com/help/releases/R2022b/sps/powersys/ref/threephasevimeasurement.html?s_tid=answers_rc2-2_p5_MLT#mw_cc57ca93-0087-4114-ab86-75abd29f91b0

When the “phase-to-ground" option is selected, the block measures the voltage w.r.t the electrical ground, which measures the correct voltage for the 4-wire system when the neutral is grounded. If the neutral is not connected to the electrical ground, the workaround is to measure the neutral voltage using a separate voltage sensor with respect to ground before subtracting it from the output of the “Three-Phase VI Measurement” block that measures the phase to ground voltages. This entire system can be wrapped in a subsystem for easy use. The subsystem can further be masked to create custom parameter fields. You can refer to this documentation to know more about how to create a mask:

https://www.mathworks.com/help/releases/R2022b/simulink/ug/block-masks.html

I hope this helps with the query.