Please could someone can explain, what will happen if (MHI SC1F-25) 120 MW steam turbine generator breaker open manually by operator on 06 MW load and tripped it by emergency push button, while its any Governor valve is stuck opened on minimum opening.
This machine is equipped with four GV and two upstream MSV.
Will machine go on over speed?
If you have 6 MW (600 KW), which is a very low load on that 120 MW machine, it is very unlikely that the machine will go into overrun, because of the mass of the machine equipment which are need to be accelerated.
If the load is higher, the ESD-valve of the machine will be activated (these valve are normally built into the turbine body, because the amount of energy in the steam is pretty high and the reaction of the ESD (Emergency-Shutdown) valve need to be in about 20 ms.