KR100351427B1 - The process and device for repairing the leaks of water cooled the stator bars of the turbin generator - Google Patents

Abstract

The present invention relates to a method and apparatus for repairing a wire leaking part of a water-cooled turbine generator stator winding. The present invention relates to a water header in repairing a strand leaking part of a water header that cools a stator winding part wound inside an generator. It is intended to be able to perform without cutting.

The configuration of the present invention comprises the steps of laser cleaning the water header portion of the water header using a laser beam; Applying a brazing alloy of a material similar to the portion to be joined to the element wire of the leaked portion; Irradiating and melting the laser beam onto the brazing alloy applied to the joined portion of the element wire portion; It includes the steps of the operator monitoring the maintenance work during the application of the brazing alloy and laser beam irradiation, according to the present invention after applying the brazing powder to the leaking site using a laser head in or out of the water header laser Brazing repairs are performed by irradiating beams, which eliminates the need to cut water headers and eliminates the need to rejoin the water headers after repairs, which reduces work time and also damages insulators that can occur during post-processing. It also has the effect of disappearing at the same time.

Description

Process and device for repairing the leaks of water cooled the stator bars of the turbin generator}

The present invention relates to a method and apparatus for repairing a wire leaking part of a water-cooled turbine generator stator winding, and more particularly, in repairing a strand leaking part of a water header for cooling a stator winding part wound in an inside of a generator. The present invention relates to a method and apparatus for repairing element leaks in a water-cooled turbine generator stator winding, which can be performed without cutting the water header.

In general, the stator winding of a water-cooled turbine generator is a component that directly generates electromotive force, and must cool the heat generated by induced electromotive force.

The cooling method is divided according to the capacity of the generator. In case of a low capacity, an indirect cooling method that cools with air or hydrogen and a high capacity of 300W or more are used as a direct cooling method that circulates gas or liquid cooling water into the hollow element wire.

Among these cooling methods, the stator windings using water cooling are composed of small hollow strands with empty interiors and solid strands with internal fillings, which are made of Cu-P brazing. They are also brazed to the inner wall of the water header.

1 is a schematic view of a stator winding (Stator bar) used in a water-cooled generator, in which the coolant is introduced from the inlet coolant tube (5) and the inlet water header (3) (water) After passing through the header, the inside of the stator winding 1 is cooled and discharged through the outlet coolant tube 4 via the outlet water header 2.

In addition, the water-cooled stator winding (1) has a system consisting of a hollow element wire (9) and a solid element wire and a method consisting of only a hollow element wire (9), both of the method between the element wire and the element wire and between the element wire and the inner wall of the water header It is brazed to a copper-phosphorus (Cu-P) alloy.

2 and 3 are water headers of water-cooled stator windings. FIG. 2 is straight water headers (2) and (3) mainly used in generator stator windings (1) of a nuclear power plant. FIG. 3 is a generator of a thermal power plant. The diagonal water headers 2 'and 3' mainly used in the stator winding 1 are shown.

Both methods supply coolant through the water header inlet 8 and inside the water header chamber 6 the elements 9 are brazed to each other as mentioned above and made of thick insulation 7 to withstand earth voltage. Are stacked.

4 is a cross-sectional view taken along the line AA ′ of FIGS. 2 and 3 showing the inside of the water header 3 between the hollow element 9 forming a stator winding and between the hollow element 9 and the inner wall of the water header chamber 6. There is a brazing joint 11

However, this brazing junction 11 has structural corrosion in the form of corrosion due to various factors such as chemical reaction between the coolant and the brazing alloy when the stator winding is used for a long period of time, and these defects continue to progress and the insulator ( If it reaches up to 7), the insulators will be damaged and the coolant may leak between them, leading to a power plant accident.

In order to prevent this, the repair method of US 5,793,014, which is proposed in the prior art, removes the cap of the water header in which the coolant flows into the interior, cleans the repaired area using a laser beam, applies the brazing filler material with a spray gun, and then A method of joining and repairing a brazing filler metal using a beam has been proposed.

However, the above method can efficiently repair the defective brazing area without cutting the water header itself using the laser beam, but after repairing the water cap must be bonded to the brazing again. In addition to the troublesome problem, the brazing filler metal is sprayed on the repaired area, so if the coating film is thin and a crack or a deep crack of 0.3 mm or more occurs in the brazing area due to impact or corrosion, it is difficult to apply and the brazing filler metal is simultaneously applied to the hollow element. In addition to the disadvantages.

Meanwhile, a method of brazing and repairing defects such as pores of a wire brazing joint after cutting of a water header covering one end of a stator winding by using a brazing filler material of a copper-phosphorus (Cu-P) alloy, such as US 5,581,869, may include Permanent robustness can be obtained, but since the water header must be brazed again, the insulator can be damaged in the process and the work process can take 90 days or more.

In addition, in the US 5,875,539 low-viscosity vacuum penetration repair method, after removing the water header insulator, apply a low-viscosity, natural curable resin to the outside of the water header from which the insulator is removed, and then the inside of the water header. By inducing a vacuum to the natural curable resin penetrates into the defect site of the wire.

However, this method is also useful when it is difficult to find the exact location of the leaked part, but there is a disadvantage in that it needs to be reinstalled after removing the insulator due to the lack of permanence and robustness of the repaired part by the natural curable resin.

The epoxy curing method of US 5,605,590 is a method of repairing by curing epoxy after applying epoxy to the leaking area using a borescope and injector without cutting the water header, and shortening working time without damaging the insulator without cutting the water header. However, the robustness and permanence of the repaired part is not guaranteed.

The present invention is to solve all the problems shown in the existing invention, it is an object of the present invention to provide a method for repairing a permanent, durable and stable leaking site without cutting the water head.

As a proper repairing method for this purpose, in the present invention, a copper-phosphorous filler metal, which is the same material as the brazing joint of the stator winding wire, not epoxy, is made in powder form so that it can be easily applied to the leaking site, and the optical fiber We propose a method and apparatus for repairing the wire leaking part of the stator winding of a water-cooled turbine generator stator that can be fostered by fusing a laser beam onto the coated powder and applying heat after condensing through a laser beam head that can be remotely transmitted. .

It is possible to obtain a permanent and solid repair site without damaging the insulator because it does not need to cut the water header by applying the powder filler material for growth using a powder injector and melting and growing using a remote laser transmission laser beam.

1 is a schematic diagram of a generator stator winding of a general water cooling method,

2 is a cross-sectional view of a water header in the form of a straight line for cooling the turbine generator stator winding to which the present invention is applied;

3 is a cross-sectional view of an oblique water header for cooling a turbine generator stator winding to which the present invention is applied;

4 is a cross-sectional view taken along line AA ′ of FIGS. 2 and 3;

5 is a cross-sectional view showing a process of applying a powder to a leaking portion inside the water header according to the present invention;

6 is a cross-sectional view showing a state of repairing the leaking portion of the straight water header from the outside from the outside.

7 is a cross-sectional view showing a process for repairing a leaking portion of an oblique water header according to the present invention from the outside;

8 is a block diagram showing the concept of an optical system of a straight laser head according to the present invention,

Figure 9 is a block diagram of the process of repairing the leakage site between the element wire and the wall surface of the straight water header according to the present invention,

10 is a cross-sectional view showing a leak site repair process between the element wire and the wall surface of the diagonal water header according to the present invention;

11 is a conceptual diagram illustrating an optical system of a diagonal laser head according to the present invention;

12 is a cross-sectional view of a straight laser head and a diagonal laser head according to the present invention;

13 is a process block diagram showing the steps of the method for repairing the wire leaking part of the water-cooled turbine generator stator winding according to the present invention.

<Description of the reference numerals for the main parts of the drawings>

1: stator winding 2; Outlet Water Header

3: inlet water header 4: outlet side coolant tube

5: Inlet side coolant tube 6: Water header chamber

7: insulator 8: water header inlet

9: hollow strands 10: electrical connection terminal

11: brazing joint 12: straight laser head

13: endoscope 14: optical fiber

15 cable 16 monitor

17 laser beam 18 lens

19: diagonal laser head 20: wedge lens

21: lens casing 22: protective glass

23: gas passage 24: optical fiber coupling portion

25: manipulator coupling portion 26: gas passage

27: hole 28: powder injector

In order to achieve the above object, the present invention is to perform the repair work on the strand leaking part of the water header to cool the stator winding portion of the water-cooled turbine generator,

Laser cleaning the water header portion of the water header using a laser beam; Applying a brazing alloy of a material similar to the portion to be joined to the element wire of the leaked portion; Irradiating and melting the laser beam onto the brazing alloy applied to the joined portion of the element wire portion; The operator comprises the steps of monitoring the maintenance work state during the application of the brazing alloy and laser beam irradiation.

In still another aspect of the present invention, in performing a repair operation of a water header strand leaking part for cooling a stator winding part wound in a water-cooled turbine generator,

Brazing alloy powder injection means for applying brazing alloy powder to the repair portion of the stator element wire; Laser irradiation means for cleaning the repaired part of the stator element and melting the alloy applied to the bonded part of the leaked part; It is characterized in that it comprises a means for visually monitoring the repair portion of the element leakage inside the water header.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 13, the method for repairing the wire leaking part of the water-cooled turbine generator stator winding of the present invention is largely performed in the stator winding leaking part laser cleaning step, brazing alloy powder applying step, brazing alloy melting growth step, and monitoring these steps during operation. It consists of steps.

Since the cleaning step of the repairing part of the stator winding leakage part of the present invention repairs the leaking part without cutting the water header, the cleaning of the leaking part before applying the brazing alloy is performed by laser cleaning technology. Use

The linear laser head 12 and the oblique laser head 19 are selected and inserted into the water header inlet 8 according to the position of the repaired part, and the leaked part is irradiated with the laser beam 17 of appropriate output for cleaning. The oxide of the site is removed.

5 is a process showing the step of applying the brazing alloy to the leaking site, the first brazing alloy to be used in the powder form (50 ~ 100㎛ by selecting a low melting point alloy of the AWS standard BCuP series and BAg series similar to the leaking site) )

Application of the powder brazing alloy is performed by mixing a powder and a heat-evaporating solvent in a syringe-type powder injector 28 and inserting it into the inside through the water header inlet 8 and the endoscope 13 and the monitor 16 having a small diameter. While checking the inside through the powder injection controller is applied while adjusting the feed rate appropriately.

FIG. 6 is a process of irradiating a laser beam 17 after applying a brazing alloy to the leaking portions of the straight water headers 2 and 3, and in the section C, the straight laser head 12 is inserted from the outside without being inserted into the inside. As a workable section, it is easier to monitor because it is easier to monitor than to insert it inside.

As can be seen in FIG. 6, since the work can be performed without cutting the water headers 2 and 3, there is no need to reassemble the water headers 2 and 3 after the repair, thus influencing the insulator 7 at all. Does not give.

In addition, when the laser beam 17 is irradiated to melt the brazing alloy applied to the leaking site, the degree of thermal effect of the surroundings is 100 ° C. or less, which is much lower than the heat effect temperature of 150-170 ° C. of the insulator.

The range of the section C of FIG. 6 varies depending on the shape of the water headers 2 and 3, and when the laser beam 17 is irradiated between the workable edges of the water header inlet 8, between the two laser beams. Is equal to the angle θ.

For laser oscillators, it is important to select a model that is easy to move to the power plant site, and continuous wave lasers are advantageous over pulse type.

7 is a process of irradiating the laser beam 11 after applying the brazing alloy to the leaking portions of the diagonal water headers 2 'and 3', as in the case of the straight water headers 2 and 3, The BC section that can be worked on is easier to work than inserting the laser head 12.

8 shows the configuration of the optical system design of the straight laser head 12 that can work outside of the water header (2), (3), the laser beam transmitted through the optical fiber 14 to collect the lens 18 for condensing Through this method is to form a laser beam 17 having a large depth of focus.

FIG. 9 shows the brazing area between the element wire 9 and the water header 2, 3 wall which cannot be repaired using the straight laser head 12 outside the water header 2, 3, ie, FIG. As a process for repairing sections B and D of 6, a diagonal laser head 19 is inserted through the water header inlet 8 to irradiate the laser beam 17 onto the brazing alloy powder already applied to the leaking site. It is a process.

At this time, unlike when using the straight laser head 12, the endoscope 13 is also inserted into the interior through the water header inlet (8).

FIG. 11 is a conceptual diagram of an optical system design of an oblique laser head 19 for refracting the laser beam 17 at an angle of 35 degrees for transmission of the laser beam 17 to a brazing part which is inoperable by the straight laser head 12.

A wedge or prism type lens 20 is used to deflect the laser beam 17, and the laser beam 17 is transmitted to the desired brazing portion through the condensing lens 18. Be sure to

12 is a cross-sectional view showing a straight and oblique laser head structure, where FIG. 12 (a) shows a straight laser head 12 and FIG. 12 (b) shows a diagonal laser head 19.

The structure of the laser heads 12 and 19 is largely composed of a lens casing 21, an optical fiber coupling part 24, and a coupling part 25 for coupling to a robot or a manipulator. do.

An inert cooling gas 26, such as argon (Ar) gas, is used to cool the lens 18 installed inside the laser heads 12 and 19. Each lens 18 is cooled through a gas passage 23 composed of a groove.

In particular, in the case of the oblique laser head 19, since the head is inserted into the water headers 2 and 3, the lens 18 is affected by the soot generated during repair of the coupling portion, and thus the laser beam 17 ) Use a protective gas to prevent problems.

The lens casing 21 and the coupler 25 can be separated and coupled, and the coupling of the coupler 25 with a robot or a manipulator is made through a hole 27.

As described above, the present invention uses a powder injector to apply the brazing powder to the leaking site, and then irradiates a laser beam inside or outside the water header using a laser head to repair and repair the brazing area. No need to cut

Therefore, it is not necessary to cut the water header, thereby eliminating the process of re-joining the water header after maintenance, thereby reducing the work time, and at the same time having the effect of eliminating the damage of the insulator that may occur during the post process.

Claims (15)

In performing repair work on the strand leaking part of the water header to cool the stator winding part wound inside the water-cooled turbine generator, Laser cleaning the water header portion of the water header using a laser beam; Applying a brazing alloy of a material similar to the portion to be joined to the element wire of the leaked portion; Irradiating and melting the laser beam onto the brazing alloy applied to the joined portion of the element wire portion; A method for repairing an element leaking part of a water-cooled turbine generator stator winding, comprising the steps of an operator monitoring a repair operation state when applying a brazing alloy and irradiating a laser beam. The method of claim 1, wherein the laser cleaning step removes dust and oxide by irradiating a portion to be repaired with a laser output such that the brazing junction is not melted by manipulating a laser head connected to an optical fiber outside or inside the water header. A method for repairing element leaks in a water-cooled turbine generator stator winding. The method of claim 1, wherein the brazing alloy of the material similar to the portion to be joined to the element wire of the leaking part is made of a material having a low melting point and excellent wettability among the brazing alloys of the same material as that of the element wire of the water header. Method for repairing the wire leaking part of the water-cooled turbine generator stator winding, characterized in that the powder is mixed with the molten material and applied to the repair part by a powder injector. [4] The method of claim 3, wherein the brazing alloy is formed of an alloy having the lowest melting point among the BCuP series and the BAg series of the AWS standard. 4. The method of claim 3, wherein the brazing alloy is made of fine particles (50-100 µm) in powder form. The method of claim 1, wherein the step of fusion bonding by irradiating a laser beam onto the brazing alloy applied to the bonded portion of the water header element wire part comprises inserting a laser head into the water header inlet and then applying the laser beam to the bonded portion of the element wire element. A method for repairing element leaks in a stator winding of a water cooled turbine generator characterized by melting a brazing alloy by irradiating a laser beam. According to claim 1, wherein the step of the operator monitoring the repair operation state during the application of the brazing alloy and laser beam irradiation (Inserting the wire wire brazing joints by inserting an endoscope equipped with a lens at the end to the water header inlet and A method for repairing a wire leaking part of a stator winding of a water-cooled turbine generator characterized by photographing a junction between an element wire and a water header wall and transmitting the cable to a monitor, which is a display device. In performing the repair work of the water header strand leaking part to cool the stator winding part wound inside the water-cooled turbine generator, Brazing alloy powder injection means for applying brazing alloy powder to the repair portion of the stator element wire; Laser irradiation means for cleaning the repaired part of the stator element and melting the alloy applied to the bonded part of the leaked part; A device for repairing element leaks in a water-cooled turbine generator stator winding, comprising means for visually monitoring the element leaks in a water header. The method of claim 8, wherein the brazing alloy powder injection means comprises a powder injector in the form of a syringe; A powder injection controller for supplying the brazing alloy powder to the powder injector and controlling the pressure; An element leakage repair device for a water-cooled turbine generator stator winding, comprising a supply pipe connecting them. 9. The apparatus of claim 8, wherein the laser irradiation means comprises: a laser oscillator for oscillating a laser; An optical fiber for transmitting the laser to the repair portion flexibly; A water-cooled turbine generator stator winding, characterized in that it consists of a straight and a diagonal laser head which is connected to one end of the optical fiber and finally forms an irradiation nozzle of the laser and at the same time a device for concentrating the laser oscillated by the laser oscillator. Repair device for element leak. 9. The apparatus of claim 8, wherein the means for visually monitoring the repairing part of the wire leaking part in the water header is inserted into the water header inlet to photograph the repairing part; A cable connecting the endoscope and the monitor; An element leak repair device for a water-cooled turbine generator stator winding, comprising a monitor connected to an endoscope and gable to display the inside of the water header. 11. The laser beam of claim 8 and 10, wherein the straight laser head comprises: a combiner connected to a robot or a manipulator which is a remote control means; A rod-shaped lens casing structurally integrated with the coupler and having a cylindrical inner diameter therein and a nozzle at the end thereof; Two or more condensing lenses coupled to the inside of the lens casing to condense the laser; A protective glass coupled to the nozzle portion of the lens casing to isolate the inside of the laser head from the outside; A wedge type lens for polarizing the laser so as to correspond to the nozzle angle of the lens casing; An element leakage repair device for a water-cooled turbine generator stator winding, which is made of an inert cooling gas that is injected and filled into the lens casing to cool the inside of the laser head. 11. The apparatus of claim 10, wherein the diagonal laser head comprises: a combiner connected to a robot or a manipulator which is a remote control means; A lens casing structurally integrated with the coupler, the lens casing having an inner diameter of the cylinder and a nozzle having an angle at an end thereof; Two or more condensing lenses coupled to the inside of the lens casing to condense the laser; A wedge-shaped lens positioned between the condenser lenses and refracting the laser to correspond to the nozzle angle of the lens casing; An element leakage repair device for a water-cooled turbine generator stator winding, which is made of an inert cooling gas that is injected and filled into the lens casing to cool the inside of the laser head. The device for repairing an element leaking part of a water-cooled turbine generator stator winding according to claim 11 or 12, wherein the inert cooling gas injected into the laser head is made of argon (Ar). 13. The element wire of the water-cooled turbine generator stator winding according to claim 11 or 12, wherein the inert cooling gas filled into the lens casing is injected into a plurality of gas passages formed based on the center point of the vertical section of the case. Leakage repair device.