CN105099032B - A kind of double week mixing transposition stator bars of large turbo-type generator and double week mixing interchanging methods - Google Patents

Abstract

The invention discloses a kind of double week mixing transposition stator bars of large turbo-type generator and double week mixing interchanging methods.Four column transposition strands of the stator bar include outer layer replace strand and internal layer transposition strand, outer layer replace strand than internal layer transposition strand number more than 4；The external sheath insulating barrier of internal layer transposition strand；The all interchanging methods of this pair each replace to internal layer transposition strand and outer layer transposition strand, and transposition by twisting is in opposite direction；The method causes that every transposition strand occupies the left side of stator winding groove portion and the locus on right side with having equal opportunities, so as to the distribution of stray field in equalizing tank well, efficiently reduce the circulation loss between strand, the service life and safety in operation of generator are improved, while tying up and fixed more convenient for transposition strand.

Description

A Large Turbine Generator Bicycle Hybrid Transposition Stator Rod and Bicycle Hybrid Transposition method

technical field

The invention relates to the technical field of design and manufacture of a large turbogenerator, in particular to a bicircular mixed transposition stator bar of a large turbogenerator and a bicircular mixed transposition method for the stator bar.

Background technique

The stator bar is one of the important parts of the turbogenerator. The stator bar of the large turbogenerator mainly adopts the bar type bar. In order to reduce the eddy current loss caused by the skin effect in the bar, dozens of However, due to the difference in the leakage flux linkage between each parallel branch, unbalanced leakage inductance potential and strand circulation are generated in the strands; the test results show that the large generator stator The temperature difference between the strands in the wire rod can be as high as 30-40°C, which greatly reduces the efficiency of the generator and seriously affects the insulation life and operation safety of the stator winding.

The four-row transposed strands of the double-robel transposition method used in the traditional turbogenerator stator bars can only realize the transposition of the two rows of strands on the left and the two rows of strands on the right, respectively, and then mirror symmetry. A single transposed strand using this transposition method cannot occupy the left and right spaces of the stator winding slot at the same time, resulting in uneven distribution of the leakage magnetic field in the slot, not only the current difference between each strand, but also the There is also a certain difference in the current of the strands between the rows. The current distribution of the strands is unbalanced, resulting in a large circulation loss and a short service life of the motor; in addition, the left and right strands of the stator bars are respectively transposed , It is not conducive to the overall binding and fixing of the wire rod in the process.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a large-scale turbogenerator bicircular hybrid transposition stator bar, which solves the problem of the large circulation loss in the existing stator bar which leads to the safety of generator operation. low problem.

Another object of the present invention is to provide a method for double-circle hybrid transposition of large turbogenerator stator bars, so that each transposed strand can equally occupy the space positions on the left and right sides of the stator winding slot, Therefore, the distribution of the leakage magnetic field in the groove can be well balanced, the circulation loss between the strands can be effectively reduced, the service life and operation safety of the generator can be improved, and at the same time, it is more convenient to bind and fix the transposed strands.

In order to achieve the above-mentioned purpose of the invention, a technical scheme that the present invention adopts is:

A large-scale turbogenerator double-circle hybrid transposition stator bar, including transposition strands arranged in four rows horizontally;

The four rows of transposed strands include outer transposed strands and inner transposed strands; the outer transposed strands include the left outer transposed strands and The right outer transposed strand at the far right of the stator bar; the inner transposed strand includes the left inner transposed strand and the right inner transposed strand located in the middle of the stator bar ;

At the end of the stator winding, the outer layer of transposed strands and the inner layer of transposed strands are connected through a parallel headgear;

The number of transposed strands in the outer layer is four more than the number of transposed strands in the inner layer; wherein, the number of transposed strands in the left outer layer is two more than the number of transposed strands in the left inner layer ; The number of transposed strands in the outer layer on the right side is two more than the number of transposed strands in the inner layer on the right side;

The outer surface of the transposed strands in the inner layer is coated with an outer insulating layer for strengthening insulation protection.

The outer layer of each transposed strand is coated sequentially from the inside to the outside with an enamelled insulation layer and a double glass fiber-wrapped insulation layer for strengthening insulation protection.

The above-mentioned two-week mixed transposition method for the stator bar of a large turbogenerator includes:

The left outer layer transposed strands and the right outer layer transposed strands in the outer layer transposed strands are transposed, and the left inner layer transposed strands in the inner layer transposed strands and The inner transposition strand on the right is transposed, and the twist transposition direction in the transposition strand in the outer layer is opposite to that in the transposition strand in the inner layer, so that each stator bar The transposed strands will equally occupy the space positions on the left and right sides of the stator winding slot to reduce circulation loss.

The specific process of transposing the left outer layer transposition strand and the right outer layer transposition strand is:

A. In the slot of the stator winding, the transposed strand on the left side moves away from the notch by a distance of the height of the transposed strand, and the transposed strand on the right side moves a distance away from the notch. The distance of the bit strand height;

B. The transposition strand farthest from the direction of the notch in the left outer transposition strand moves to the position farthest from the notch in the right outer transposition strand, and the closest to the right outer transposition strand The transposed strand in the direction of the notch moves to the position closest to the notch among the transposed strands in the outer layer on the left;

C. The outer transposition strand on the left side moves a distance of transposition strand height away from the notch, and the outer transposition strand on the right side moves a distance of transposition strand height towards the direction close to the notch. Realize a transposition of the outer transposition strand;

D. The left outer layer transposition strand and the right outer layer transposition strand in the outer layer transposition strands continue to transpose according to the transposition sequence of steps A to C until reaching the outer layer transposition strand The design transposition angle.

The specific process of transposition of the left inner layer transposition strand and the right inner layer transposition strand is:

E. In the slot of the stator winding, the right inner transposed strand moves away from the notch for a distance of transposed strand height, and the left inner transposed strand moves one transposed strand towards the notch. The distance of the bit strand height;

F. The transposition strand farthest from the direction of the notch in the right inner transposition strand moves to the position farthest from the notch in the left inner transposition strand, and the closest to the left inner transposition strand The transposed strand in the direction of the notch moves to the position closest to the notch among the transposed strands in the inner layer on the right;

G. The inner transposition strand on the right side moves a distance of the height of the transposition strand away from the notch, and the inner transposition strand on the left side moves a distance of the height of the transposition strand towards the direction close to the notch. Realize one-time transposition of inner transposition strands;

H. The right inner layer transposition strand and the left inner layer transposition strand in the inner layer transposition strands continue to transpose according to the transposition sequence of steps E to G until reaching the inner layer transposition strand Design transposition angles.

After the transposed strands of the outer layer and the transposed strands of the inner layer are respectively transposed, since the number of transposed strands of the outer layer of the stator bar is four more than the number of transposed strands of the inner layer, the outer layer of the stator bar The transposition strand is larger than the inner layer transposition strand in the overall structure, therefore, the inner layer transposition strand is embedded in the free space in the center of the outer layer transposition strand;

The transposed pitches and transposed angles of the transposed strands of the outer layer and the transposed strands of the inner layer can be kept the same or different according to design requirements.

The beneficial effects of the present invention are:

1) The stator bar of the present invention adopts the design of the structure of the outer layer transposition strand and the inner layer transposition strand, and the outer layer transposition strand and the inner layer transposition strand are respectively transposed in opposite torsional transposition directions , so that each transposed strand can evenly occupy the space position on the left and right of the slot of the stator bar, and the distribution of the leakage magnetic field in the slot is more uniform, thereby effectively reducing the strand circulation loss and improving the service life and operation safety of the generator sex.

2) The inner layer of transposed strands in the stator bar of the present invention is located between the outer layer of transposed strands, which is more conducive to bundling and fixing of the transposed strands as a whole.

Description of drawings

Fig. 1 is a structural schematic diagram of an embodiment of a large-scale turbogenerator double-cycle hybrid transposition stator bar of the present invention.

Fig. 2 is a perspective view of an embodiment of the bicircular mixed transposition of the stator bar of the large turbogenerator according to the present invention.

FIG. 3 is a top view of FIG. 2 .

Fig. 4 is a perspective view of an embodiment of twisted transposition of the inner transposed strands of the present invention.

Fig. 5 is a perspective view of an embodiment of twisted transposition of the transposed outer strands of the present invention.

Fig. 6 is a perspective view when the stator bar in Fig. 1 is transposed by one pitch.

FIG. 7 is a top view of FIG. 6 .

Fig. 8 is a cross-sectional view of the transposed strand in Fig. 7 at the transposed position A-A.

Fig. 9 is a cross-sectional view of the transposed strand in Fig. 7 at the transposed position B-B.

Fig. 10 is a cross-sectional view of the transposed strand in Fig. 7 at transposed position C-C.

Fig. 11 is a cross-sectional view of transposed strands in transposed position D-D in Fig. 7 .

Fig. 12 is a cross-sectional view of the transposed strand in Fig. 7 at the transposed position E-E.

detailed description

The specific embodiments of the present invention are described below so that those skilled in the art can understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

According to an embodiment of the present application, referring to Fig. 1, Fig. 1 shows a schematic structural diagram of an embodiment of a large-scale turbogenerator bicircular hybrid transposition stator bar; Bit strands; the four columns of transposed strands include outer transposed strands 1 and inner transposed strands 2, and at the end of the stator winding, the outer transposed strands and the inner transposed strands pass through a and headgear connected;

The outer layer transposed strands include the left outer layer transposed strands located on the far left side of the stator bar and the right outer layer transposed strands located on the far right side of the stator bar, the left outer layer transposed strands and The outer transposition strands on the right are composed of 15 transposition strands; the inner transposition strands include the left inner transposition strands and the right inner transposition strands located in the middle of the stator bar, and the left Both the side inner layer transposed strands and the right inner layer transposed strands are composed of 13 transposed strands; the number of outer layer transposed strands is four more than the number of inner layer transposed strands.

Moreover, the outer surface of the inner layer of transposed strands is coated with an outer insulating layer 3 to strengthen the insulation protection between the outer layer of transposed strands and the inner layer of transposed strands; the outer layer of each transposed strand The layers are sequentially covered with an enamelled insulating layer and a double glass fiber wrapped insulating layer for enhanced insulation protection from the inside to the outside.

According to an embodiment of the present application, referring to Fig. 2 to Fig. 5, Fig. 2 is a perspective view of an embodiment of a double-circle hybrid transposition of the stator bar of a large turbogenerator according to the present invention; Fig. 3 is a top view of Fig. 2; Fig. 4 It is a three-dimensional structure diagram of the inner transposition strand in Fig. 1 and Fig. 2 undergoing torsion transposition, and Fig. 5 is a three-dimensional structural diagram of the outer transposition strand in Fig. 1 and Fig. 2 undergoing torsion transposition; as shown in FIG. As shown in 2, the outer layer transposition strands of the stator bar are composed of the left outer layer transposition strands and the right outer layer transposition strands, and each row is composed of 15 transposition strands; the inner layer transposition The strands are composed of the left inner layer transposition strands and the right inner layer transposition strands, and each column is composed of 13 transposition strands; as shown in Figure 4 and Figure 5, the inner layer transposition strands and The outer transposition strands are transposed according to the transposition angle, and the inner transposition strands are transposed between the two rows in the middle of the stator bar according to the design of the transposition pitch and the corresponding torsional transposition direction; Layer-transposed strands are transposed between the leftmost row and the rightmost row of stator bars according to the design of the transposition pitch, and the twisting and transposition directions of the inner layer transposition strands and the outer layer transposition strands are opposite , the transposition pitches and transposition angles of the outer layer transposition strands and the inner layer transposition strands can be kept different according to design requirements; the outer layer transposition strands and the inner layer transposition strands respectively The transposition process is as follows:

Referring to Figure 6 and Figure 7, Figure 6 is a perspective view of the stator bar in Figure 1 and Figure 2 at a transposition pitch; Figure 7 is a top view of Figure 6; as shown in Figure 6 and Figure 7, the A-A position is The starting position of the strand transposition, its cross-sectional view is shown in Figure 8; the specific transposition method is:

Before the left outer transposition strand begins to transpose to the right outer transposition strand, the left outer transposition strand moves away from the notch for a distance of one transposition strand height; the right outer transposition strand Before the transposition strand starts to transpose towards the outer transposition strand on the left side, the transposition strand on the right outer layer moves towards the direction close to the notch by a distance of transposition strand height; similarly, the inner layer transposition strand of the stator bar The right inner transposed strand in the bit strand starts moving towards the left inner transposed strand before transposing the right inner transposed strand moves away from the notch by a distance of one transposed strand height ;Before the left inner transposition strand begins to transpose to the right inner transposition strand, the left inner transposition strand moves towards the direction close to the notch by a distance of transposition strand height, which is the strand Make preparations across the rows until the B-B position, its cross-sectional view is shown in Figure 9.

After ensuring that the strands can be transposed between rows along the groove width direction, carry out inter-row transposition on the left outer layer transposition strand 15 and the right outer layer transposition strand 30, and the left outer layer transposition strand The transposition strand 15 farthest away from the notch in the right outer layer transposition strand moves to the position farthest from the notch in the right outer layer transposition strand, and the transposition strand 30 closest to the notch in the right outer layer transposition strand moves to The position closest to the notch in the left outer layer of transposed strands; similarly, row-to-row transposition is performed on the left inner layer transposed strand 31 and the right inner layer transposed strand 44, and the right inner layer transposed The transposition strand 44 farthest away from the notch in the strands moves to the position farthest from the notch among the left inner layer transposition strands, and the transposition strand 31 closest to the notch in the left inner layer transposition strands Move to the position closest to the notch in the inner transposition strand on the right side; C-C is the middle position in the inter-row transposition, and its cross-sectional view is shown in Figure 10.

When the left side outer layer transposition strand 15 and the right side outer layer transposition strand 30 completely complete inter-row transposition, and the left side inner layer transposition strand 31 and the right side inner layer transposition strand 44 complete After the inter-row transposition is completed, the position D-D is reached. At this time, the left outer layer transposed strand 15 is higher than the right outer layer transposed strand 16 along the direction away from the notch, and the right outer layer transposed strand 30 is higher than the right outer layer transposed strand 30. The direction near the notch is higher than the left outer layer transposition strand 1; similarly, the right inner layer transposition strand 44 is higher than the left side inner layer transposition strand 43 along the direction away from the notch, and the left inner layer The transposition strand 31 is higher than the inner layer transposition strand 56 on the right side along the direction close to the notch, and its cross-sectional view is shown in FIG. 11 .

In order to ensure that the strands maintain the same spatial position along the axial direction during the process of transposition, the outer transposition strand on the left side moves a distance of the height of the transposition strand away from the notch, and the outer transposition strand on the right side The line moves toward the direction close to the notch by a distance of the height of the transposed strand; similarly, the transposed strand of the inner layer on the right side of the stator bar moves a distance of the height of the transposed strand away from the notch, and the inner layer of the left side The transposed strands move toward the direction close to the notch by a distance of the height of the transposed strands, and all the strands reach the corresponding position E-E after completing one transposition, and its cross-sectional view is shown in FIG. 12 .

The inner transposed strands and the outer transposed strands of the stator bar continue to be transposed sequentially in accordance with the transposition sequence shown in Figure 8 to Figure 12, and always keep the opposite twist transposition direction until the strands complete the required transposition number of positions or angle of transposition.

According to an embodiment of the present application, the transposed pitch length and the transposed angle of the transposed strands of the inner layer and the transposed strands of the outer layer can be kept different according to design requirements.

The hybrid transposition method of the stator bar of the present invention can not only meet the design requirements of different transposition pitches and transposition angles, but also because the two rows of transposition strands in the inner layer and the two rows of transposition strands in the outer layer are mutually transposed and The direction of twisting and transposition is opposite, and each transposed strand will equally occupy the space position on the left and right of the groove, and the distribution of the leakage magnetic field of the slot is more uniform, which is beneficial to reduce the circulation loss of the strands; at the same time, the inner two rows The bit strands are located between the two rows of transposition strands in the outer layer, which is beneficial to the binding and fixing of the transposition strands as a whole.

Claims (8)

1. A large-scale turbo-generator bicyclic mixed transposition stator bar, including transposition strands arranged horizontally in four rows; it is characterized in that: The four columns of transposed strands are divided into outer transposed strands and inner transposed strands; the outer transposed strands include a left outer transposed strand located on the leftmost side of the stator bar and the right outer transposed strand located at the far right of the stator bar; the inner transposed strand includes a left inner transposed strand and a right inner transposed strand located in the middle of the stator bar Wire; At the end of the stator winding, the outer layer of transposed strands and the inner layer of transposed strands are connected through a parallel headgear; The number of transposed strands in the outer layer is four more than the number of transposed strands in the inner layer; The outer surface of the transposed strands in the inner layer is coated with an outer insulating layer for strengthening insulation protection. 2. The large-scale turbogenerator double-cycle hybrid transposition stator bar as claimed in claim 1, characterized in that: The number of transposed strands on the left outer layer is two more than the number of transposed strands on the left inner layer; the number of transposed strands on the right outer layer is greater than the number of transposed strands on the right inner layer Two more. 3. The large-scale turbogenerator double-cycle hybrid transposition stator bar according to claim 1 or 2, characterized in that: The outer layer of the transposed strand is covered sequentially from the inside to the outside with an enamelled insulation layer and a double glass fiber-wrapped insulation layer for strengthening insulation protection. 4. A bi-circular hybrid transposition method for a stator bar according to any one of claims 1 to 3, characterized in that it comprises: The left outer layer transposed strands and the right outer layer transposed strands in the outer layer transposed strands are transposed, and the left inner layer transposed strands in the inner layer transposed strands and The inner transposition strand on the right is transposed, and the twist transposition direction in the transposition strand in the outer layer is opposite to that in the transposition strand in the inner layer, so that each stator bar The transposed strands will equally occupy the space positions on the left and right sides of the stator winding slot to reduce circulation loss. 5. The bicircular hybrid transposition method of stator bar as claimed in claim 4, further comprising: After the transposed strands of the outer layer and the transposed strands of the inner layer are respectively transposed, the transposed strands of the inner layer are embedded in the spatial position of the center of the transposed strands of the outer layer. 6. The biweekly hybrid transposition method of stator bar as claimed in claim 4, characterized in that, the transposition pitch and transposition angle of the respective transposition of the outer transposition strands and the inner transposition strands Keep the same or different according to design needs. 7. The biweekly mixed transposition method for stator wire rods as claimed in claim 4, characterized in that, the specific process of transposing the left outer layer transposition strands and the right outer layer transposition strands is: A. In the slot of the stator winding, the transposed strand on the left side moves away from the notch by a distance of the height of the transposed strand, and the transposed strand on the right side moves a distance away from the notch. The distance of the bit strand height; B. The transposition strand farthest from the direction of the notch in the left outer transposition strand moves to the position farthest from the notch in the right outer transposition strand, and the closest to the right outer transposition strand The transposed strand in the direction of the notch moves to the position closest to the notch among the transposed strands in the outer layer on the left; C. The outer transposition strand on the left side moves a distance of transposition strand height away from the notch, and the outer transposition strand on the right side moves a distance of transposition strand height towards the direction close to the notch. Realize a transposition of the outer transposition strand; D. The left outer layer transposition strand and the right outer layer transposition strand in the outer layer transposition strands continue to transpose according to the transposition sequence of steps A to C until reaching the outer layer transposition strand The design transposition angle. 8. The biweekly mixed transposition method for stator wire rods as claimed in claim 4, characterized in that, the specific process of transposing the left inner layer transposition strands and the right inner layer transposition strands is: E. In the slot of the stator winding, the right inner transposed strand moves away from the notch for a distance of transposed strand height, and the left inner transposed strand moves one transposed strand towards the notch. The distance of the bit strand height; F. The transposition strand farthest from the direction of the notch in the right inner transposition strand moves to the position farthest from the notch in the left inner transposition strand, and the closest to the left inner transposition strand The transposed strand in the direction of the notch moves to the position closest to the notch among the transposed strands in the inner layer on the right; G. The inner transposition strand on the right side moves a distance of the height of the transposition strand away from the notch, and the inner transposition strand on the left side moves a distance of the height of the transposition strand towards the direction close to the notch. Realize one-time transposition of inner transposition strands; H. The right inner layer transposition strand and the left inner layer transposition strand in the inner layer transposition strands continue to transpose according to the transposition sequence of steps E to G until reaching the inner layer transposition strand Design transposition angles.