When I calculate self sealing load point on 500MW steam turbine,
I couldn't assume inlet of N2 packing pressure & enthalpy.
At this time, I assumed the pressure as HP bowl pressure and the
enthalpy as
average value between HP bowl enthalpy and HP 1st stage shell one.

but I couldn't believe this assumption because there is no steam balance hole on HP 1st Nozzle.

If there is steam balance hole on HP 1st Nozzle, I think my assumption is reasonable.

I couldn't derived a reasonable value for inlet of N2 packing without balance hole. How can I get the reasonable value for self sealing load point calculation?

but I couldn't believe this assumption because there is no steam balance hole on HP 1st Nozzle.

If there is steam balance hole on HP 1st Nozzle, I think my assumption is reasonable.

I couldn't derived a reasonable value for inlet of N2 packing without balance hole. How can I get the reasonable value for self sealing load point calculation?