JPH0515095A - Coil for high voltage rotary electric machine and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a coil for a high voltage rotary electric machine, having excellent end corona and surface flashover preventing performance by providing an end corona preventive layer formed by integrally impregnating a semiconductive high resistance tape layer lap wound in a predetermined width on both ends of a low resistance tape layer with thermosetting resin, and thermally curing it. CONSTITUTION:An insulating tape layer 3 formed by winding an insulating tape containing peeling mica or aggregate mica as a main ingredient in a predetermined thickness, a low resistance tape layer 4 formed by winding a semiconductive low resistance tape at an outside, and a high resistance tape layer 5 formed by winding a semiconductive high resistance tape in a predetermined width having laps at both ends of the tape 4, are taped on a coil conductor 2 made of an array of a plurality of insulator-coated strand conductors and having a substantially longitudinal section. The tape layers are simultaneously impregnated in vacuum or under pressure with thermosetting resin 6, charged in a mold, and thermally cured to secure the layers 3, 5 to each other to be integrated, thereby forming a coil 1 for a high voltage rotary electric machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage rotating machine coil which constitutes a stator winding of a high-voltage turbine generator or a turbine generator, and a method for manufacturing the same, and more particularly, to an end at both ends of an outer corona preventive layer. The present invention relates to a high voltage rotating machine coil having a corona prevention layer and a method for manufacturing the same.

[0002]

2. Description of the Related Art A high-voltage rotating machine coil, which constitutes a stator winding of a high-voltage turbine generator or a turbine generator, is used while being housed in a slot of a stator iron core. During operation of the rotating machine, there is a potential difference of several KV to tens of KV with respect to the grounded stator core, so if there is a gap between the two, discharge (called partial discharge or corona discharge) occurs in the gap. Damage the main insulation layer,
Further, it has a bad effect such as corroding the coil conductor and the iron core. Therefore, as a method of manufacturing the main insulating layer, an insulating tape mainly composed of mica having excellent corona resistance is wound around the outer circumference of the aligned coil conductor with a predetermined thickness and well dried, and then thermosetting epoxy resin or the like. The resin is impregnated under vacuum pressure so as not to leave air bubbles, and then stored in a mold to adjust the shape and dimensions, and the impregnated resin is heat-cured to eliminate corona generation sources such as voids. Moreover, the main insulating layer having excellent corona resistance is formed. A method in which the resin is housed in a mold, and then the resin is impregnated under vacuum pressure and heat cured is also used.

Further, since the void existing between the main insulating layer and the slot also becomes a source of corona discharge (also referred to as external corona), a semiconductive low resistance paint is applied to the surface of the main insulating layer. An outer corona-preventing layer having a thickness of about 0.1 mm is formed, and is configured to be in conductive contact with the stator core.
By setting the surface resistivity of the external corona preventive layer in the range of about 5 to 10 KΩ, the potential of the external corona preventive layer is brought close to the ground potential to prevent the generation of external corona, and the circulating current flows to the external corona preventive layer. Prevents heat generation and potential rise due to flow.

Further, an electric field is concentrated on both ends of the outer corona preventive layer in a knife-edge shape, and corona discharge (called end corona) is generated to damage the main insulating layer. Also,
During the withstand voltage test of the stator winding, creeping discharge occurs and the withstand voltage performance deteriorates. Therefore, a semi-conductive high resistance coating is applied to the end of the external corona preventive layer with a predetermined width having an overlap and a dried end corona preventive layer is provided, and the voltage drooping characteristic of the resistance is used to make the external corona preventive layer. Measures are taken to mitigate the electric field concentration at the edges.

On the other hand, in the high voltage rotating machine coil which requires a lot of processing man-hours for the insulation treatment, it is required to rationalize its manufacturing method and to improve withstand voltage performance and heat resistance performance. Therefore, as a part of that, following the taping work of the main insulating tape layer, a semi-conductive low resistance tape is wound around the outer side of the main insulation tape layer with a predetermined thickness to form a high resistance tape layer, A method for simultaneously impregnating a main insulating tape layer and a high resistance tape layer with a thermosetting resin and heat curing to simultaneously form a main insulating layer and an external corona preventive layer has been proposed by the applicant of the present application. There is.

[Problems to be Solved by the Invention] A semiconductive coating material is uniformly applied to the surface of the main insulating layer to form a thickness of 0.1 mm.
The conventional method of forming a moderate external corona prevention layer requires a high degree of skill to form a uniform coating film, and the coating time and curing time also increase, which increases the manufacturing cost of the high-voltage rotating machine coil. In addition, there is a problem that the external corona easily occurs locally due to the non-uniformity of the thickness of the coating film. On the other hand, in the method using the semiconductive low resistance tape, the outer corona preventive layer having a uniform thickness reinforced by the fiber base material of the low resistance tape is integrally impregnated into the main insulating layer. It firmly adheres, highly exhibits the function of preventing external corona and heat stability, and eliminates the work of applying low-resistance paint and the drying process, which has the advantage of streamlining the manufacturing process of high-voltage rotating machine coils. can get.

However, the end corona preventive layer has a semi-conductive high resistance coating material having a predetermined width having an overlap with the end of the outer corona preventive layer after the processing of the main insulating layer and the outer corona preventive layer is completed. A method of applying and further heat-drying to form an end corona preventive layer having a uniform thickness of, for example, about 0.4 mm is adopted, and not only a high level of technology is required for the application work, but also the drying time. Therefore, it is required to rationalize the manufacturing process of the end corona preventive layer. In addition, the coating-type end corona preventive layer does not have sufficient mechanical strength, and the end corona preventive layer is partially peeled off when the high voltage rotating machine coil is inserted into the slot, and the end corona preventive function deteriorates. Or, there is a problem that the prevention function of the end corona is reduced by moisture absorption of the coating film, it is necessary to apply a protective coating on the outside of the end corona prevention layer in order to avoid such a problem,
The manufacturing of this protective coating also requires a lot of processing man-hours, which causes a problem that the manufacturing process of the high voltage rotating machine coil becomes more complicated. Further, the high resistance coating material containing fine powder of silicon carbide, synthetic resin and solvent has a limitation in environmental hygiene such that ventilation is required at the time of applying and curing the coating material.

An object of the present invention is to provide an end corona preventive layer which has a uniform thickness and is strong and has no damage at the time of inserting a slot, and therefore can stably obtain excellent end corona preventive performance, and a streamlined manufacturing method thereof. Is to get.

[0009]

In order to solve the above problems, according to the present invention, a coil conductor, an insulating tape layer wound on the outside thereof, and an outer circumference of the insulating tape layer are wound. In a molded coil of a high voltage rotating machine having a main insulating layer formed by impregnating a thermosetting resin into the semiconductive low resistance tape layer and heat curing, and a low resistance tape as described above. A semi-conductive high resistance tape layer wound at a predetermined width and having an overlap at both ends of the layer is integrally impregnated with the thermosetting resin together with the insulating tape layer and the low resistance tape layer, It shall be provided with an end-corona preventive layer formed by heating and curing.

Further, it is assumed that the semiconductive high resistance tape is obtained by impregnating a thin fiber tape as a base material thereof with a liquid high resistance paint.

Further, the end-corona preventive layer has a protective coating formed by integrally impregnating a thermosetting resin on a heat-shrinkable polyester tape wound on the outside of the high resistance tape layer and curing by heating. And

On the other hand, a series of steps for manufacturing a coil for a high-voltage rotating machine includes a step of winding an insulating tape containing mica around a coil conductor to a predetermined thickness to form an insulating tape layer, and a half of the outer circumference thereof. A step of winding a conductive low resistance tape in a predetermined thickness to form a low resistance tape layer, and holding a semi-conductive high resistance tape in a predetermined width while keeping overlapping at both ends thereof. And a step of forming a high-resistance tape layer by winding with, and a step of impregnating each of the tape layers with a thermosetting resin under vacuum and pressure at the same time.

[0013]

The semiconductive high resistance tape layer having a predetermined width is formed on both ends of the semiconductive low resistance tape layer wound around the outer periphery of the main insulating tape layer. This high resistance test
Since the thermosetting resin is integrally impregnated with the insulating tape layer and the low-resistance tape layer in the coating layer, the end corona-preventing layer obtained by heating and curing is formed. Since it is a layer, it maintains a uniform thickness and forms the end corona preventive layer firmly adhered to the main insulating layer and the outer corona preventive layer by the reinforcing action of the base material and the adhesive action of the impregnated resin. It is possible to obtain an end corona preventive layer which is excellent in preventing end corona and creeping on the surface by preventing uneven coating and peeling during work.

If a semiconductive high resistance tape is made by impregnating a thin fiber tape as a base material with a liquid high resistance paint, it can be uniformly applied by a simple taping operation. It is possible to easily form an end corona preventive layer having a uniform thickness and to obtain an end corona preventive layer having the same drooping resistance as the end corona preventive layer made of a high resistance paint.

Further, the end corona preventive layer has a protective coating formed by integrally impregnating a thermosetting resin on a heat-shrinkable polyester tape layer wound on the outer side of the high resistance tape layer and heat curing. According to this structure, it is possible to form a protective coating that is strong and has excellent moisture resistance with almost no increase in the number of steps.

On the other hand, in a series of steps for manufacturing a coil for a high voltage rotating machine, a series of taping operations, a single thermosetting resin impregnation, and a main insulating layer of uniform thickness are formed by a heat hardening step. Since the corona prevention layer and the end corona prevention layer are firmly fixed and integrated, and the protective coating can be integrated, the work of applying the high resistance paint and the drying process are not required. A function that greatly simplifies the process is obtained.

[0017]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a cross-sectional view showing a coil of a high-voltage rotating machine according to an embodiment of the present invention. The coil conductor 3 is composed of an array of a plurality of wire conductors covered with an insulating material and has a substantially rectangular cross section. An insulating tape layer in which an insulating tape mainly composed of mica or laminated mica is wound in a predetermined thickness, and a low resistance tape layer in which a semiconductive low resistance tape is wound on the outside thereof. A high resistance tape layer formed by winding a semiconductive high resistance tape having a predetermined width and having an overlap at both ends of the low resistance tape layer is taped to each tape layer. At the same time, the thermosetting resin 6 is impregnated with vacuum and pressure, and is housed in a mold and subjected to heat curing treatment, so that the main insulating layer 3, the outer corona preventing layer 4, and the end corona preventing layer 5 are cured of the impregnated resin. The high-voltage rotating machine coil 1 is formed by being firmly fixed to each other by an object.

As the semiconductive high resistance tape, a thin glass (fiber) tape or a polyester (fiber) tape is used for the base material, and silicon carbide fine powder is used as the main component for the base material. A test piece that has been dried and soaked with a liquid high-resistance paint.
Are used. For example, as a commercially available tape,
SEMI CONDUCTIVE CORONA PROTECT made by ISOLA, Switzerland
ION TAPE No.217.01, No217.02, No217.03, SGT-X2 tape made by Nippon Mica Mfg. Co., Ltd. can be used.

FIG. 2 is a characteristic diagram showing the voltage dependence of the volume resistivity of the end corona preventive layer according to the example, and the characteristic obtained in the example is shown by a curve 11 in the conventional case of a high resistance coating film. The characteristics of the end corona preventive layer are shown in curve 12 as a comparative example. In the figure, the decrease of the volume resistivity with respect to the increase of the applied voltage (voltage drooping characteristic) is close to both curves, and it can be seen from this figure that even if a high resistance tape is used for the end corona preventive layer, It was found that the same end-corona preventive performance as that of the conventional end-corona preventive layer using is obtained.

Table 1 is a characteristic table showing the end corona starting voltage and the creeping voltage of the surface of the end corona preventive layer according to the embodiment in comparison with those of the conventional one, and high voltage rotation having the end corona preventive layer according to the embodiment. The end corona starting voltage and creeping peak voltage of the machine coil show values equal to or higher than those of the comparative example.

[0021]

[Table 1]

The end corona-preventing layer having the above-mentioned structure is formed by a single impregnation of a thermosetting resin and a heat-curing step, and is integrated with the main insulating layer and the outer corona-preventing layer to form a strong and uniform end. Since the corona preventive layer can be formed, a high voltage rotating machine coil having an end corona preventive layer excellent in stability can be obtained without deterioration in performance due to uneven coating of the high resistance paint or damage due to external force. In addition, since the post-processing such as the application work of the high resistance paint and the heating and hardening process for which high skill is required is not required, the manufacturing process of the high voltage rotating machine coil can be greatly simplified.

FIG. 3 is a sectional view of a coil of a high voltage rotating machine showing a different embodiment of the present invention.
The difference from the above-mentioned embodiment is that a protective coating 7 is provided on the outside. The protective coating 7 is formed by winding one or two layers of heat-shrinkable polyester fiber tape on the outside of the high-resistance tape layer, impregnating a thermosetting resin together with the main insulating layer, and heat-curing the resin. It Therefore, the insulating tape layer and the high resistance tape layer are integrated with the protective coating by the resin-impregnated cured product in a state where the insulating tape layer and the high-resistance tape layer are bound by the polyester tape.
The end corona preventive layer is mechanically reinforced and the moisture resistance performance is improved.

FIG. 4 is a flow chart showing a series of manufacturing steps of the high voltage rotating machine coil. The main insulating layer is taped, the outer corona preventive layer is taped, and the end corona preventive layer is taped. In addition, the protective coating taping step is continuously formed by a series of steps only by changing the tape to be used, and each tape is formed by a single impregnation of the thermosetting resin and a heat curing step. The layers are firmly integrated, and post-processing to form the end corona preventive layer and protective coating is almost unnecessary, which greatly simplifies the manufacturing process of the high voltage rotating machine coil. It has been found that it is possible to reduce about 10% of the winding man-hours and about 8% of the manufacturing cost as compared with the conventional manufacturing method in which the end corona preventive layer is post-processed.

[0025]

As described above, according to the present invention, the semi-conductive low-resistance tape layer wound around the outer periphery of the main insulating tape layer has a predetermined width and is semi-conductive at both ends. A high-resistance tape layer is formed, and a thermosetting resin is integrally impregnated with the insulating tape layer and the low-resistance tape layer in the high-resistance tape layer, and an end corona preventive layer is formed by heat curing. did.
As a result, by the reinforcing action of the base material of the high resistance tape and the adhesive action of the impregnating resin, it is possible to easily form the end corona preventive layer having a uniform thickness firmly fixed to the main insulating layer and the outer corona preventive layer. Eliminates the problems of conventional end-corona preventive layers using high-resistance paint, such as advanced coating technology for obtaining a uniform thickness, uneven coating of high-resistance paint, and performance deterioration due to mechanical damage. Thus, it is possible to provide a high-voltage rotating machine coil provided with an end corona preventive layer having excellent end corona and creeping surface creeping preventive performance.

Further, if the semiconductive high resistance tape is made by impregnating a thin fiber tape as a base material with a semiconductive, liquid high resistance paint, the tape is simplified. -Pinging operation makes it possible to easily form an end corona preventive layer having a uniform thickness, and to obtain an end corona preventive layer having the same drooping characteristic of resistance as the end corona preventive layer made of a high resistance paint, and therefore, the end corona and It is possible to provide a high-voltage rotating machine coil provided with an end corona preventive layer having an excellent performance of preventing creeping on the surface.

Further, the end corona preventive layer has a protective coating formed by integrally impregnating a heat-curable resin on a heat-shrinkable polyester tape layer wound on the outside of the high resistance tape layer and heat-curing it. According to this structure, a strong protective coating excellent in moisture resistance can be formed with almost no increase in man-hours, and thus a high-voltage rotating machine coil having a highly reliable end corona preventive layer is provided. be able to.

On the other hand, in the method for manufacturing a high voltage rotating machine coil of the present invention, a series of tapes in which the insulating tape layer, the low resistance tape layer and the high resistance tape layer are different are used. −
High voltage rotating machine coil that is continuously formed by the ping process, and is integrated with the main insulating layer, the external corona prevention layer, and the end corona prevention layer that are firmly fixed and integrated in a single thermosetting resin impregnation and heat curing process. In addition to manufacturing the high voltage paint, the process of applying high resistance paint, the drying process, and the protective coating process, which were previously performed as post-processing, are almost unnecessary. It is significantly rationalized, and for example, it is possible to reduce the winding man-hours by about 10% and the manufacturing cost by about 8% compared to the conventional manufacturing method in which the end corona preventive layer is post-processed by using a high resistance paint. Therefore, there is an advantage that it can contribute to the cost reduction of the high voltage rotating machine.

[Brief description of drawings]

FIG. 1 is a sectional view showing a high-voltage rotating machine coil according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the voltage dependence of the volume resistivity of the end corona preventive layer according to the example.

FIG. 3 is a sectional view of a high-voltage rotating machine coil showing a different embodiment of the present invention.

FIG. 4 is a flowchart showing a series of manufacturing steps of a high voltage rotating machine coil according to an embodiment of the present invention.

[Explanation of symbols]

1 High voltage rotating machine coil 2 Coil conductor (aligned conductor) 3 Main insulation layer (including insulation tape layer) 4 External corona prevention layer (including low resistance tape layer) 5 End corona prevention layer (including high resistance tape layer) 6 Thermosetting resin (impregnating resin) 7 Protective coating (including heat-shrinkable polyester tape)

Claims (4)

[Claims] 1. A thermosetting resin is applied to a coil conductor, an insulating tape layer wound on the outside thereof, and a semiconductive low resistance tape layer wound on the outer periphery of the insulating tape layer. In a shaping coil of a high-voltage rotating machine having a main insulating layer formed by impregnation and heat curing and an external corona preventing layer, a semi-conductive coil wound with a predetermined width having an overlap on each end of the low resistance tape layer. A high resistance tape layer is provided with an end corona preventive layer formed by integrally impregnating the thermosetting resin together with the insulating tape layer and the low resistance tape layer and heat curing. Voltage rotating machine coil. 2. A high conductive tape according to claim 1, characterized in that a thin fiber tape as a base material of said semiconductive tape is impregnated with a liquid high resistance paint. Voltage rotating machine coil. 3. The end corona preventive layer has a protective coating formed by integrally impregnating a heat-curable resin on a heat-shrinkable polyester tape wound on the outer side of a high resistance tape layer and heat curing. The high voltage rotating machine coil according to claim 1. 4. A series of steps for manufacturing a high-voltage rotating machine coil comprises winding an insulating tape containing mica around a coil conductor to a predetermined thickness to form an insulating tape layer, and forming a semi-insulating layer around the insulating tape layer. A step of winding a conductive low resistance tape in a predetermined thickness to form a low resistance tape layer, and holding a semi-conductive high resistance tape in a predetermined width while keeping overlapping at both ends thereof. 2. The method according to claim 1, further comprising: a step of winding a high resistance tape layer to form a high resistance tape layer; and a step of simultaneously impregnating each of the tape layers with a thermosetting resin under vacuum and pressure. High voltage rotating machine coil manufacturing method.