JPH09289750A - Cooling water supply device - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To use a copper tube of a stator coil of a generator, and to reduce the amount of dissolved oxygen in water when flowing water into the copper tube to cool the cupric oxide on the surface of the copper tube. It has been found that is difficult to generate and the long life of the coil is shortened. [Structure] An oxygen amount is supplied to a cooling water system in accordance with a measurement result of a dissolved oxygen measuring device 12 provided in a cooling water system using a copper tube for a stator coil 6, and dissolved oxygen in water is controlled to a predetermined amount. [Effect] Since the second oxide film on the surface of the copper pipe can be generated and maintained by controlling the amount of oxygen in the water, it is possible to prevent the thinning of the copper pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water supply device made of a copper pipe, and more particularly to a cooling water supply device for a turbine generator.

[0002]

2. Description of the Related Art In general, in electric equipment, in addition to increasing the capacity of the equipment, cooling the inside of the equipment is important for ensuring the performance of the equipment and miniaturizing the equipment. In large turbine generators, a "water cooling system" has been widely used in which hydrogen gas is enclosed in the machine and water is passed inside the stator coil. A typical water system for a water-cooled turbine generator is shown in FIG.

In the cooling water supply apparatus for a turbine generator, the water in the water tank 1 is pressurized by the pump 2, brought to a predetermined temperature by the cooler 3, passed through the filter 4, and then the stator coil 6 of the generator 5 is supplied. A closed circuit is formed by passing through the inside and returning to the water storage tank 1.

Further, in this apparatus, in order to keep the cooling water as pure water, the purity maintaining circuit 8 for supplying a part of the water to the ion exchange resin 7 and the hydrogen gas stored in the water storage tank are discharged to the outside. An exhaust pipe 9 is provided for this purpose.

As shown in FIGS. 5 and 6, the stator coil 6 is composed of a hollow copper tube 10 and has an insulating layer 11 on its surface, and has a structure in which cooling water is passed through the hollow portion. .

In such a water-cooled turbine generator, the hollow copper tube 10 of the stator coil 6 is corroded and water is leaked during operation, or an oxide film corroded and dropped adheres to the filter, or inside the water system. Due to the accumulation, there was a case where a problem of obstructing the flow of the cooling water occurred.

[0007] The cause of these problems is copper oxide produced when the hollow copper tube 10 of the stator coil 6 and dissolved oxygen in water are combined, but cuprous oxide (produced when dissolved oxygen is particularly small) Since Cu ₂ O) is easily peeled off, by repeating generation → peeling → generation, corrosion thinning of the copper pipe 10 progresses and, at the same time, it adheres and deposits on the inner wall of the hollow copper pipe to cause water flow inhibition. I understood. In the experiment, it was confirmed that in the region where the oxygen content is lower than 1 ppm, the higher the water temperature, the more the corrosion progresses. On the other hand, when the amount of dissolved oxygen is large, cupric oxide, which is structurally strong and difficult to peel off, is generated on the copper surface, so that corrosion does not proceed. Generally, the saturated amount of oxygen with respect to water is about 8 ppm at room temperature, but in the actual measurement of the amount of dissolved oxygen that is cooled by the turbine generator, a machine that drops to about 0.01 ppm within a few months after replenishing with new water by regular inspection, It was found that there are some that maintain 3 ppm or more.

[0008]

Comparing these operating conditions, when the load fluctuation of the generator is large, the oxygen concentration tends to be higher than that of the case where the fluctuation is small. This is because when the load fluctuates a lot, the temperature of the generator stator coil changes, so the volume of water in the water tank changes and the water surface position fluctuates, so that the atmosphere breathes through the exhaust pipe. As a result, new oxygen is supplied to the water surface in the water tank and taken into the water, whereas in a machine with a small load fluctuation, there is no breathing action, so there is no new oxygen supply, and the copper of the stator coil is not supplied. It is presumed that, since copper oxide forms copper oxide, dissolved oxygen is consumed and the amount of oxygen decreases with time.

As described above, even in generators of the same design, the amount of dissolved oxygen in cooling water differs depending on the operation, and problems such as corrosion thinning of copper pipes and clogging of water systems occur. It has been required to develop a water supply device that controls the amount of dissolved oxygen in water to generate and maintain cupric oxide on the surface of a copper tube and considers the extension of the life of the coil. As a water cooling and supplying device for a generator, there is JP-A-50-50604.

It is an object of the present invention to provide a cooling water supply device which extends the life of a copper pipe by preventing the corrosion of the copper pipe by forming and maintaining a cupric oxide film on the inner surface of the copper pipe.

[0011]

The cooling water supply device of the present invention comprises a device for measuring the amount of dissolved oxygen in a water cooling passage made of a copper pipe, and a predetermined amount of dissolved oxygen based on the measurement result. And a control unit for supplying the inside.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

The cooling system of the generator is a water tank 1 for supplying water.
Is pressurized by the pump 2, supplied to the generator 5 through the cooler 3 and the filter 4, cools the stator coil 6 of the generator 5, and then returns to the water tank 1 to form a closed circuit. . The inside of the stator coil 6 is a hollow copper pipe made of a copper material,
Circulate cooling water. The closed circuit has a filter 4 and a generator 5
When a dissolved oxygen measuring device 12 is provided between the oxygen supply valve 10 and the oxygen detector, and the detected oxygen concentration falls below a specified value, the oxygen supply valve control device 13 operates the oxygen supply valve 14 to supply oxygen 15 into the water from the oxygen supply port 20. Supply and control the amount of dissolved oxygen.

According to this embodiment, since the amount of dissolved oxygen in the cooling water supplied to the generator 5 can be controlled, cupric oxide having high corrosion resistance is produced on the surface of the copper pipe of the stator coil 6. A water supply device that can be maintained and takes into consideration the long life of the coil can be obtained.

In addition to the above-mentioned embodiment, the oxygen supply valve is installed at a position A from the ion exchange resin to the water storage tank, a position B from the generator to the water storage tank, and further, as shown in FIG. The same effect can be obtained by arranging in the upper space of the water storage tank as in C.

Further, instead of oxygen supplied to water, a gas containing oxygen, for example, clean air or pure air (air obtained by degassing carbon dioxide gas) may be used, and in some cases, water containing a large amount of oxygen. The same effect can be obtained by using. In either case, it is necessary to set the amount of dissolved oxygen to 1 ppm or more.

The above embodiment is intended to generate cupric oxide on the surface of the coil copper tube during operation of the generator, but as shown in FIG. 2, a large amount of oxygen is contained before starting the generator. It is also possible to heat the deionized water to 50 ° C. or higher by the heater 15 provided in the circuit and supply it to the coil to forcibly form the cupric oxide film. After this pretreatment, if the generator is operated by the above-mentioned water supply device for controlling the amount of dissolved oxygen, a more stable film can be maintained, so that the reliability against corrosion can be improved.

The embodiment of the present invention shown in FIGS. 1 and 2 can be applied not only to a newly installed machine but also to an existing machine currently in operation. When the oxygen supply valve controller 13 operates the oxygen supply valve 14 to supply oxygen 15 into the water through the oxygen supply port 20 to control the dissolved oxygen amount, the dissolved oxygen amount is not controlled for the life of the coil 6, as shown in FIG. The life can be extended compared to the case.

[0019]

According to the present invention, the amount of dissolved oxygen in water is controlled to form cupric oxide on the surface of a copper pipe in order to prevent corrosion thinning of the copper pipe and clogging of the water system. It is possible to obtain the water supply device that maintains the life of the coil.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cooling water system of a turbine generator according to the present invention.

FIG. 2 is a cooling water system configuration diagram of a turbine generator when a cupric oxide film is attached.

FIG. 3 is a characteristic diagram showing a tendency of thinning of a copper pipe according to an example of the present invention.

FIG. 4 is a configuration diagram of a cooling water system of a turbine generator according to a conventional technique.

5 is a partial detailed view of the generator showing the stator coil of FIG. 4. FIG.

6 is a cross-sectional view of the coil taken along the line E of FIG.

[Explanation of symbols]

1 ... Water tank, 2 ... Pump, 3 ... Cooler, 4 ... Filter,
5 ... Generator, 6 ... Stator coil, 7 ... Ion exchange resin,
8 ... Purity maintaining circuit, 9 ... Exhaust pipe, 10 ... Copper pipe, 11 ... Insulating layer, 12 ... Dissolved oxygen measuring device, 13 ... Oxygen supply valve control device, 14 ... Oxygen supply valve, 15 ... Oxygen, 20 ... Oxygen supply mouth.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kayoko Ishikawa 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Kazuo Goto 3-chome, Saiwaicho, Hitachi, Ibaraki No. 1 Hitachi Ltd., Hitachi Plant (72) Inventor Takeshi Saito 3-1, 1-1 Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd. (72) Inventor, Takashi Honda Honda Mika, Ibaraki Prefecture 7-1-1, Machi, Hitachi Co., Ltd. Hitachi Research Laboratory

Claims (4)

[Claims] 1. A cooling water supply device comprising a copper pipe, a device for measuring the amount of dissolved oxygen in the cooling water supply device, and a controller for supplying a predetermined amount of dissolved oxygen to the water cooling passage based on the measurement result. And a cooling water supply device. 2. A cooling water supply device comprising a copper pipe, wherein a copper coil for flowing cooling water inside a stator coil of a rotating electric machine is used, and the copper pipe is connected to a water storage tank through cooling passages connected to both ends of the copper pipe. Then, connect the oxygen supply section to the water tank via the supply valve, input the result of measuring the dissolved oxygen amount of the cooling water in a part of the cooling passage with the measuring instrument to the control section, and then supply the supply valve from the control section. Control
The cooling water supply device according to claim 1, wherein a predetermined amount of oxygen is supplied to the water tank. 3. The cooling water supply system according to claim 1, wherein the control unit controls the amount of dissolved oxygen to be 1 ppm or more. 4. The cooling water supply apparatus according to claim 1, wherein the dissolved oxygen amount is supplied to the copper pipe cooling water system to maintain the cupric oxide film in the cooling water system.