Turbine cooling apparatus

Abstract

A turbine cooling apparatus of an embodiment includes a cooling air supply unit and a control unit The control unit controls an operation of the cooling air supply unit during a turning operation. Here, the control unit controls the operation of the cooling air supply unit to make the cooling air supply unit supply the cooling air at a previously determined flow rate. Thereafter, the control unit controls the operation of the cooling air supply unit based on at least either of a result obtained by measuring differential expansion between a turbine rotor and a turbine casing, and a result obtained by measuring a temperature difference between an inner peripheral surface of a steam chamber positioned at an entrance of a steam flow path through which steam flows in the turbine casing and an outer peripheral surface of the steam chamber.

What is claimed is: 
     
         1 . A turbine cooling apparatus for cooling a steam turbine having a turbine casing and a turbine rotor housed in an inner part of the turbine casing, the turbine cooling apparatus comprising:
 a cooling air supply unit configured to supply cooling air to the inner part of the turbine casing; and   a control unit configured to control an operation of the cooling air supply unit during a turning operation, wherein   the control unit controls the operation of the cooling air supply unit to make the cooling air supply unit supply the cooling air at a previously determined flow rate, and then controls the operation of the cooling air supply unit based on at least either of a result obtained by measuring differential expansion between the turbine rotor and the turbine casing, and a result obtained by measuring a temperature difference between an inner peripheral surface of a steam chamber positioned at an entrance of a steam flow path through which steam flows in the turbine casing and an outer peripheral surface of the steam chamber.   
     
     
         2 . The turbine cooling apparatus according to  claim 1 ,
 wherein the turbine casing has:
 an inner casing housing the turbine rotor in an inner part thereof; and 
 an outer casing housing the inner casing in an inner part thereof; 
   the cooling air supply unit comprises:
 a first cooling air supply part configured to supply the cooling air to the inner part of the inner casing; and 
 a second cooling air supply part configured to supply the cooling air to a space between the inner casing and the outer casing; and 
   the control unit controls operations of the first cooling air supply part and the second cooling air supply part to make the first cooling air supply part and the second cooling air supply part supply the cooling air at a previously determined flow rate, and then controls the operations of the first cooling air supply part and the second cooling air supply part based on at least either of the result obtained by measuring the differential expansion, and the result obtained by measuring the temperature difference.   
     
     
         3 . The turbine cooling apparatus according to  claim 2 ,
 wherein the turbine cooling apparatus is configured to make the cooling air supplied by the second cooling air supply part flow along a rotation axis of the turbine rotor, in the space between the inner casing and the outer casing.   
     
     
         4 . The turbine cooling apparatus according to  claim 3 , further comprising
 tubular bodies extending along a radial direction of the turbine rotor,   wherein the tubular bodies include cooling air releasing ports penetrating to be along the rotation axis of the turbine rotor, and the cooling air supplied by the second cooling air supply part flows from the cooling air releasing ports to the space between the inner casing and the outer casing.   
     
     
         5 . The turbine cooling apparatus according to  claim 4 ,
 wherein the tubular bodies comprise:
 a first tubular body; and 
 a second tubular body, 
   wherein the cooling air releasing ports are formed on each of the first tubular body and the second tubular body.   
     
     
         6 . The turbine cooling apparatus according to  claim 3 , further comprising
 a cooling air releasing pipe disposed to surround an outer peripheral surface of the inner casing,   wherein a plurality of cooling air releasing ports releasing the cooling air are formed on the cooling air releasing pipe, the plurality of cooling air releasing ports are arranged, at equal intervals, in a periphery of the outer peripheral surface of the inner casing, and the cooling air supplied by the second cooling air supply part flows from each of the plurality of cooling air releasing ports to the space between the inner casing and the outer casing.