Method for cooling a steam turbine
View Patent ↗An automation system that determines the theoretical maximum rate of cooling of a steam turbine and operates a steam generator in such a way that the thermal energy of the steam does not exceed nor drop below the predefined rate of cooling.
1. A method for cooling a steam turbine, comprising:
operating a steam generator during a cooling operation comprising a boiler blow-off or a change in firing effective to reduce a power of the steam generator,
charging the steam turbine with steam from the steam generator during the cooling operation,
determining a predefined cooling rate {dot over (T)} vor of the steam turbine,
determining an actual cooling rate {dot over (T)} tat during the cooling operation and comparing the actual cooling rate {dot over (T)} tat with the predefined cooling rate {dot over (T)} vor , and controlling operation of the steam generator during the cooling operation such that the actual cooling rate {dot over (T)} tat corresponds to the predefined cooling rate {dot over (T)} vor .
2. The method as claimed in claim 1 ,
wherein the predefined cooling rate {dot over (T)} vor is determined using a finite element method, is determined by measurements, or is determined by testing.
3. The method as claimed in claim 1 ,
wherein the actual cooling rate takes into account temperatures of components of the steam turbine.
4. The method as claimed in claim 3 , further comprising:
determining a temperature at an inner casing wall T I and a temperature at an outer casing wall T A and ensuring a difference in temperature T A −T I remains within predefined limits.
5. An automation system,
wherein the automation system is designed for carrying out a method as claimed in claim 1 .