Method and apparatus for cold starting a steam turbine

Abstract

The disclosure relates to a method and apparatus for cold starting a steam turbine by preheating a steam turbine component using eddy currents. The process includes providing an electrically conducting steam turbine component, an electro-magnetic coil, and a supply of AC to the coil. The coil is located relative to the component so that the coil is capable of forming eddy currents in the component. In this location, an AC current is passed through the coil thus heating the component.

1 . A method for preheating a steam turbine component comprising:
 providing an electro-magnetic coil;   locating the coil relative to the steam turbine component so that the coil forms eddy currents in the steam turbine component when AC is applied to the coil;   providing AC to the coil so as to heat the steam turbine component by the eddy currents.   
     
     
         2 . The process of  claim 1  wherein the steam turbine component is a steam valve. 
     
     
         3 . The process of  claim 2  wherein the steam valve controls a flow of motive steam into the steam turbine. 
     
     
         4 . The process of  claim 1 , comprising:
 controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.   
     
     
         5 . The process of  claim 4 , comprising:
 measuring temperature of the steam turbine component; and   varying the AC based on the measured temperature.   
     
     
         6 . The process of  claim 2 , comprising:
 controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.   
     
     
         7 . The process of  claim 3 , comprising:
 controlling heating of the steam turbine component by varying AC power and frequency applied to the coil.   
     
     
         8 . An apparatus for preheating a steam turbine component, comprising:
 an electro-magnetic coil for arrangement relative to a steam turbine component so that the coil will form eddy currents in the steam turbine component when AC is applied to the coil;   a temperature measurement device for measuring a temperature of the steam turbine component; and   a controller for controlling an AC supply to the coil based on temperature of the steam turbine component.   
     
     
         9 . The apparatus of  claim 8 , wherein the steam turbine component is a steam valve. 
     
     
         10 . The apparatus of  claim 9 , wherein the steam valve controls a flow of motive steam into the steam turbine. 
     
     
         11 . The apparatus of  claim 8 , comprising:
 insulation covering the steam turbine component.