Turbine generator and operating method thereof, and nuclear power plant and operating method thereof

• US 6,459,750 B1
• Filed: 06/02/2000
• Issued: 10/01/2002
• Est. Priority Date: 06/03/1999
• Status: Expired due to Term

• Current Assignee: mitsubishi hitachi power systems, ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Itoo, Kazutoshi, Sano, Takahiko, Fujii, Kazumi, Ohashi, Kenya
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Lofdahl, Jordan M
• Application Number:
  US09/585,333
• Time in Patent Office: 851 Days
• Field of Search: 376/402
• US Class Current: 376/402
• CPC Class Codes: C02F 1/42 by ion-exchange ion-exchange in general B01J
• CPC Class Codes: H02K 9/19 for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil

Abstract

A turbine generator has a water cooling system for cooling the inside of a stator coil with water, wherein the water cooling system includes a water storage tank for storing water; pipes connecting the water storage tank and the stator coil, the pipes being provided in an inlet side and in an outlet side; a decarbonated air injection unit connected to the inlet side of the pipe by a pipe or a decarbonated air injection unit connected to the water storage tank; a heater for heating the water, the stator coil having an oxide film on a surface in contact with the water, the oxide film being formed before starting operation of the generator by high temperature water injected with the decarbonated air and heated by the heater; and a control unit for effecting control so that the decarbonated air is always and continuously injected into the cooling water during operation of the generator.

Claims

1. A turbine generator comprising a water cooling system for cooling an inside of a stator coil with water, wherein said water cooling system comprises:

a water storage tank for storing said water;

pipes connecting between said water storage tank and said stator coil, said pipes being provided in an inlet side and in an outlet side;

at least one of (a) a decarbonated air injection unit connected to said inlet side of said pipe by a pipe and (b) a decarbonated air injection unit connected to said water storage tank;

a heating means for heating said water, said stator coil having an oxide film on a surface in contact with said water, said oxide film being formed before starting operation of said generator by high temperature water injected with said decarbonated air and heated by said heating means; and

a control unit for controlling so that said decarbonated air is always and continuously injected into said cooling water during operation of said generator.

2. A turbine generator comprising a water cooling system for cooling an inside of a stator coil with water, wherein said water cooling system comprises:

a water storage tank for storing said water;

pipes connecting between said water storage tank and said stator coil, said pipes being provided in an inlet side and in an outlet side;

at least ore of (a) a decarbonated air injection unit connected to said inlet side of said pipe by a pipe and (b) a decarbonated air injection unit connected to said water storage tank;

a heating tank for heating and storing said water, and for supplying said water to said water storing tank;

a filter for removing solid objects in said water before supplying said water to said stator coil;

an ion exchange resin unit for removing ions in said water;

an oxygen concentration meter for measuring an oxygen content in said water which has passed through said filter, said stator coil having an oxide film on a surface in contact with said water, said oxide film being formed before starting operation of said generator by high temperature water injected with said decarbonated air and heated by said heating tank; and

a control unit for controlling said decarbonated air to be always and continuously injected into said cooling water in said stator coil and for controlling an amount of said decarbonated air injected into said cooling water based on a signal from said oxygen concentration meter during operation of said generator.

3. A method of operating a turbine generator comprising a stator coil an inside of which is cooled with water, the method comprising the steps of:

before starting operation of said generator, forming an oxide film on a surface of said stator coil in contact with said water by high temperature water injected with decarbonated air; and

during operation of said generator, always and continuously infecting said decarbonated air into said cooling water.

6. A method of operating a turbine generator according to any one of claims 3 to 5, the method further comprising the steps of:

measuring a concentration of oxygen dissolved in said cooling water; and

controlling an injecting amount of said decarbonated air based on said measured concentration of oxygen.

7. A method of operating a turbine generator according to claim 6, wherein said decabonating air is injected into said cooling water so that the concentration of oxygen dissolved in said cooling water does not become below 1 ppm.

4. A method of operating a turbine generator comprising a stator coil an inside of which is cooled with water, the method comprising the steps of:

before starting operation of said generator, forming an oxide film on a surface of said stator coil in contact with said water by high temperature water above 50°

C. injected with decarbonated air; and

during operation of said generator, circulating said cooling water so as to have a dissolved oxygen concentration of 1 to 4 ppm by always and continuously injecting said decarbonated air into said cooling water to continuously maintain said oxide film on the inner surface of said coil.

5. A method of operating a turbine generator comprising a stator coil an inside of which is cooled with water, the method comprising the steps of:

before starting operation of said generator, injecting an inert gas into said cooling water using an inert gas injecting leans to said cooling water, said inert gas injecting means being directly connected to a pipe connected to said stator coil, and removing corrosion products inside said stator coil and said pipe using a filter connected to said pipe;

after that, before starting operation of said generator, forming an oxide film on a surface of said stator coil in contact with said water by high temperature water above 50°

C. injected with decarbonated air; and

during operation of said generator, circulating said cooling water so as to have a dissolved oxygen concentration of 1 to 4 ppm by always and continuously injecting said decarbonated air into said cooling water to continuously maintain said oxide film on the inner surface of said coil.

8. A nuclear power plant comprising a nuclear reactor;

a steam turbine rotated by steam obtained by energy from said nuclear reactor;

a turbine generator rotated by said steam turbine, said turbine generator having a water cooling system for cooling an inside of a stator coil with water, wherein said water cooling system comprises;

a water storage tank for storing said water;

pipes connecting between said water storage tank and said stator coil, said pipes being provided in an inlet side and in an outlet side;

at least one of (a) a decarbonated air injection unit connected to said inlet side of said pipe by a pipe and (b) a decarbonated air injection unit connected to said water storage tank;

a heating means for heating said water, said stator coil having an oxide film on a surface in contact with said water, said oxide film being formed before starting operation of said generator by high temperature water injected with said decarbonated air and heated by said heating means; and

a control unit for controlling so that said decarbonated air is always and continuously injected into said cooling water during operation of said generator.

9. A nuclear power plant comprising a nuclear reactor;

a steam turbine rotated by steam obtained by energy from said nuclear reactor;

a turbine generator rotated by said steam turbine, said turbine generator having a water cooling system for cooling an inside of a stator coil with water, wherein said water cooling system comprises;

a water storage tank for storing said water;

pipes connecting between said water storage tank and said stator coil, said pipes being provided in an inlet side and in an outlet side;

at least one of (a) a decarbonated air injection unit connected to said inlet side of said pipe by a pipe and (b) a decarbonated air injection unit connected to said water storage tank;

a heating tank for heating and storing said water, and for supplying said water to said water storing tank;

a filter for removing solid objects in said water before supplying said water to said stator coil;

an ion exchange resin unit for removing ions in said water;

an oxygen concentration meter for measuring an oxygen content in said water, said stator coil having an oxide film on a surface in contact with said water which has passed through said filter, said oxide film being formed before starting operation of said generator by high temperature water injected with said decarbonated air and heated by said heating tank; and

a control unit for controlling said decarbonated air to be always and continuously injected into said cooling water in said stator coil and for controlling an amount of said decarbonated air injected into said cooling water based on a signal from said oxygen concentration meter during operation of said generator.

10. A method of operating a nuclear power plant comprising a nuclear reactor;

a steam turbine rotated by steam obtained by energy from said nuclear reactor;

a turbine generator rotated by said steam turbine, said turbine generator having a water cooling system for cooling an inside of a stator coil with water, the method comprising the steps of;

before starting operation of said generator, forming an oxide film on a surface of said stator coil in contact with said water by high temperature water above 50°

C. injected with decarbonated air; and

during operation of said generator, circulating said cooling water so as to have a dissolved oxygen concentration of 1 to 4 ppm by always and continuously injecting said decarbonated air into said cooling water to continuously maintain said oxide film on the inner surface of said coil.

11. A method of operating a nuclear power plant comprising a nuclear reactor;

a steam turbine rotated by steam obtained by energy from said nuclear reactor;

a turbine generator rotated by said steam turbine, said turbine generator having a water cooling system for cooling an inside of a stator coil with the method comprising the steps of;

before starting operation of said generator, injecting an inert gas into said cooling water using an inert gas injecting means to said cooling water, said inert gas injecting means being directly connected to a pipe connected to said stator coil, and removing corrosion products inside said stator coil and said pipe using a filter connected to said pipe;

after that, before starting operation of said generator, forming an oxide film on a surface of said stator coil in contact with said water by high temperature water above 50°

C. injected with decarbonated air; and

during operation of said generator, circulating said cooling water so as to have a dissolved oxygen concentration of 1 to 4 ppm by always and continuously injecting said decarbonated air into said cooling water to continuously maintain said oxide film on the inner surface of said coil.