Hi Irfan,
One way of doing this is by creating your own Single-phase varying load. To do this you can use the "Variable Resistor" , "Variable Capacitor" and "Variable inductor" and rearrange them to connect them in parallel or series. You use signal blocks from Simulink > Sources to control the impedence values.
You can refer this following example where a "Variable inductor" is used.
If you need to use a "Single Phase Dynamic Load" you can refer to the following example and reuse the custom built block in your model.
Hope this answers your query.
