What is the significance of V1 and V'2 in this case? (We used impeadance matching to move everything to HV side)

What is the prime (') on V2 telling us?

Thanks again.

 

The prime ' notation simply reminds the user that when employing the equivalent circuit to (say) evaluate the load side output voltage for a particular load condition, then the calculated value is referred to the primary side. Thus the applied load value would need to be transformed to an equivalent primary side value which would be 'seen' across the V'2 terminals. To find the actual load voltage V2, one would have to apply the primary-secondary turns ratio to find the value that one would actually measure on the load side.

The use of the term "impedance matching" in this context is not good practice - I would prefer to use "impedance transformation" to describe the process used in developing the equivalent circuit in terms of HV side parameters.