In the attached example the output power of a single phase load is controlled via an external file element (ElmFile). Import the project, save the text file to the hard disk and select this file in the measurement file object of the Composite Model.

The composite model frame connects the first two outputs of the file (y1, y2) to an intermediate DSL model and then to the input signals of the load Pext and Qext. In the case of single phase load the input signals (Pext and Qext) don't represent active and reactive power, as for three phase load, but admittance values. Then it is necessary to include in between a small DSL model which divides the P and Q values coming from the text file, by the load terminal voltage.

To measure the voltage a StaVmea (voltage measurement device) is necessary and has to be configured for one specific phase, a in this case.

Having a phase-neutral load requires to measure the phase-neutral voltage, this is available since V2016 in a single measurement device. Have a look at the attached project "ElmFile_1Ph_ElmLod_PhN_U.pfd" for this case.