Creating Powercircuit System by Using Python Script

So far I am able to create the circuit by using API Python code. However after I check the voltage parameter of the circuit, it shows 0V and it is a read-only parameter. Any thing I can do to set the distribution voltage for the circuit?

When we are creating a circuit in Revit, it provides us a window for selecting a suitable distribution system. But no parameter is needed for the voltage when we use python script to take the action.