JPH02155208A - High series-capacitance disc winding - Google Patents

Abstract

PURPOSE:To simplify winding work, and to improve reliability by composing a high series-capacitance disc winding of a central-section disc winding having an even number of parallel conductors, an upper-end section disc winding, which is installed to the upper end section of the central-section disc winding and parallel conductors of which are halved, and a lower-end section disc winding, which is mounted to the lower end section of the central-section disc winding and parallel number and the number of turns of which are made the same as the upper-end section disc winding. CONSTITUTION:Two conductors 1c, 1d are branched from an upper terminal 22 for their connection, and the conductor 1c is positioned on the outside diameter side of the disc coil 15 and the conductor 1d on the inside diameter side of a disc coil 16. The conductor 1c reaches to the inside diameter side in the disc coil 15 and is connected to the conductor 9c of the disc coil 16. Adjacent disc coils are mutually connected in series in a connecting section 34 on the outside diameter side and a connecting section 35 on the inside diameter side in the same manner as a normal disc winding up to immediately before the conductors 9c and 1d are unified on the inside diameter side of the disc coil 16 and connected to a disc coil 21. Lastly, two parallel conductors are integrally bonded electrically by a lower terminal 23 by a connection system reverse to the disc coil 15 in the disc coil 21.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a high-series capacitance circular winding used as a high-voltage disc winding of a transformer with improved dielectric strength against shock voltages such as lightning. Regarding plate winding.

[Conventional technology]

Lightning can be caused by direct snowfall, where lightning falls directly onto power systems connected to power transformers installed at substations, or induced lightning, which is induced into power transmission lines by nearby lightning strikes or discharges within thunderclouds. There is a phenomenon in which a sudden change in shock voltage occurs in a power system.

This shock voltage can invade power system transmission lines and connected electrical equipment such as transformers and circuit breakers, causing dielectric breakdown in power transmission lines and electrical equipment, so to avoid this, A method of protecting electrical equipment from applying a voltage higher than the permissible shock voltage by installing lightning arresters, etc. Electrical equipment such as transformers and circuit breakers are used to protect electrical equipment from the high voltage of the power system. It is specified in the standard to withstand the shock voltage according to the
In order to confirm this dielectric strength, a test was conducted in which a voltage generated by a shock voltage generator capable of simulating the shock voltage generated by lightning was applied to these electrical devices. It's called a test.

In the case of transformers, it is known that there is a problem in which the windings to which an impact voltage is applied resonate with the impact voltage, causing local voltage concentration inside the windings, and this phenomenon generally occurs. This is called potential oscillation. Particularly in the case of ultra-high voltage transformer windings, it is important to suppress potential oscillations and make the distribution of shock voltage within the windings as uniform as possible to avoid local concentration of voltage. For this purpose, a computer-based technical calculation program has been developed to simulate the potential oscillations within the winding, and research and development of the optimal winding configuration is progressing based on highly accurate calculation technology.

Disk windings have a simpler structure than other high-voltage windings, such as multilayer cylindrical windings, so they have greater mechanical strength against the magnetic force caused by external short circuits, are easier to manufacture, and have design considerations. Because it has important advantages such as high degree of freedom, it is also used in 500KV ultra-high voltage transformers. Instead, a disk winding is used which suppresses potential oscillations and has a high dielectric strength against voltage. Among the most commonly used disk S wires is a disk winding called a high series capacitance disk winding.

When an impact voltage is applied to a disk winding, the magnitude of the potential oscillation that occurs inside the winding can be approximately determined by the appearance of the potential distribution that occurs within the winding immediately after the impact voltage is applied. . This potential distribution is called the initial potential distribution, and this initial potential distribution is mainly determined by the ratio of the parallel capacitance as the ground capacitance of the number of disc turns and the series capacitance as the capacitance within the number of disc turns. Make a distribution. The distribution is such that the applied end is equal to the applied voltage and is attenuated as it penetrates into the winding, and in the case of a distribution with severe attenuation, it becomes a substantially exponential attenuation function. When this function is expressed mathematically and the variable is the number of disc coils, the coefficient on the number of disc coils, which is the variable in the exponent part, is generally expressed as α, and this α is the series capacitance of the parallel capacitance C mentioned above. It is expressed as the square root of the ratio to K.

The initial potential distribution with a large α suddenly becomes a distribution that attenuates.
When α is 0, the distribution is equal. If α is large and the number of disc coils is large enough, the voltage applied between the disc coils at the application end will be α times the voltage when the potential distribution is −-like.
The most basic measure to suppress the potential vibration caused by the impact voltage of the disk winding is to reduce the value of α.
A high series capacitance disk winding is a type of disk winding that uses a connection method that increases the series capacitance in order to reduce α.

Series capacitance is defined as an equivalent capacitance that corresponds to the sum of electrostatic energy stored in the capacitance determined by the geometrical arrangement, such as between adjacent disk coils or conductors. A calculation method based on such a definition of series capacitance is sometimes called a stored energy method.

As is well known, the electrostatic energy stored in the capacitance is one half of the product of the capacitance and the square of the voltage. Therefore, even if the capacitance determined from the geometric arrangement is the same, by devising the connection method and increasing the voltage applied to this capacitance, the series capacitance as an equivalent capacitance can be increased. Can be done.

FIG. 2 is a conductor arrangement diagram which is also a cross-sectional schematic diagram of the number of turns showing an example of a conventional high series capacitance disc winding.

This figure shows a high series capacitance disk winding consisting of two parallel conductors. , b represents the distinction between continuous conductors. That is, the conductors marked with the letter a are all connected in series to form a single electrical conductor, and the same applies to the conductors marked with the letter a. That is, the crystal series capacitance disk windings of this time are a, l! : It is a disk winding of two parallel conductors consisting of two conductors marked with b.

The two conductors branched from the upper terminal 22 first become conductors la and lb as one turn at the beginning of winding of the disc winding 11, and are then electrically connected in the order of 2a, 2b, and 3a3b. The conductors la, lb and the conductors 5a, 5b have a configuration in which four conductors are wound together, and are wound in two turns to form a disk coil 11. Similarly, the disk coils 12, 13, and 14 are structurally formed by winding four conductors together with two turns. 2 turns is the minimum number of turns shown in the drawing, and actual disk coils have various numbers of turns, usually 5 turns or more.

As shown in the figure, the disc coils 11 and 12 formed in this way have four conductors connected to each of the disc coils 11 and 12 at the connection part 31 on the left side of the figure, which is the inner diameter side, and The conductors 4a, 4b of the disc coil [2] and the conductors 5a, 5b of the disc coil 11 are connected at the connecting portion 32 of the disc coil 11. With such a connection, starting from the upper terminal 22, the conductor 1a,
The connection method is such that the disk coils 11 and 12 are rotated twice with lb as the conductor at the beginning of winding, and finally the conductors 8a and 8b are reached.

In the same way, the disk coils 13 and 14 are also connected to the circular i coil 11.
．． The conductors 9a and 9b connected to the winding end conductors 8a and 8b of No. 12 at the connecting portion 33 are used as winding start conductors and are connected in the same connection method as the disc coils 11 and 12. In this way, the two disc coils are connected as one set, and each set is connected in series, so that one
Although only seven disc coils are shown in the figure in which two high series capacitance disc windings are formed, an actual high series capacitance disc winding consists of several dozen disc coils. is normal.

In this way, by changing the degree r so that the conductor rotates in the two disk coils as the number of turns increases, the conductor at the beginning of winding and the conductor that has made one rotation can rotate one more time together. This connection method is a characteristic of high series capacity disc windings. This figure shows an example of two parallel conductors, but
High series capacitance disk windings with only one conductor or two parallel double conductors with four conductors are also in practical use.

According to the example of the six-disc coil 11, where the induced voltage between adjacent conductors is multiple times the induced voltage of one turn due to the connection method peculiar to high series capacitance disk windings, the conductor next to the conductor 1b 5a, there is a difference in induced voltage of 4 tanns.

Similarly, in the other disc coils 12, 13, and 14, the difference in the numerical values of the reference symbols of each conductor represents the magnification of the induced voltage between each adjacent conductor for one turn.

2 in the high series capacitance disk SvA of this connection method.
The series capacitance per 1111 disc coil consisting of two disc coils is calculated by dividing the sum of electrostatic energy between conductors whose induced voltage is multiple times that of one turn by the induced voltage of one set of disc coils. It becomes twice as much. Since the induced voltage per l turn is included in both the value to be divided and the value to be divided, the induced voltage per turn is a value that is irrelevant when calculating the series capacitance. In the case of a high series capacitance disk winding, the capacitance between the disk coils accounts for a small proportion of the series capacitance, so it is ignored here.

When the M product energy method is applied to the case of a set of disc coils 11 and 12 using specific numerical values, the result is as follows.

In the disc coil 11.12, the difference in induced voltage between adjacent conductors is 4 tans for conductors 1b and 5a, 2b and 6a, and 8.
There are four locations, a and 4b, and 7a and 3b, and two locations, 5b and 2a, and 4a and 7b, that correspond to three tangs. Since electrostatic energy is one-half of the product of capacitance and voltage squared, which is determined by the geometrical arrangement, the value corresponding to the total electrostatic energy is 4 times 16, which is 4 squared, which is 64. 82, which is the sum of 9, which is the square of 3, and 18, which is twice the number, is obtained.

This is 82 points when the induced voltage between adjacent conductors is only 1.7 times, as in the case where the disk coils 11 and 12 are connected not as shown but in the normal disk coil connection mode. equivalent to minutes. In the case of a normal disc coil with the same conductor arrangement as shown in Fig. 2, there are three locations between the conductors where the induced voltage of 1 line per disc coil is generated. Since there are 6 locations, the value corresponding to the electrostatic energy at this time is 6. Therefore, the second
By adopting the high series capacitance disk winding connection method as shown in the figure, the series capacitance is approximately 14 times 82 divided by 6.

The actual series capacitance per two disc coils is this value multiplied by the product of the capacitances of adjacent conductors divided by the square of the number of turns for the two disc coils. Since the actual values of capacitance and series capacitance are not relevant here, specific numerical values are omitted.

The number of turns of one disc coil in Figure 2 is 4 turns, but since the number of turns of an actual disc coil is usually large, the connection method of high series capacitance disc windings is used to connect adjacent conductors. Since the magnification of the induced voltage is also large, this difference in series capacitance becomes even larger.

[Problem to be solved by the invention]

As mentioned above, the series capacitance of the high series capacitance disk winding is increased by employing a unique connection method.

Therefore, the value of the coefficient α that determines the degree of potential oscillation when an impact voltage is applied is reduced, and as a result, the potential distribution approaches a −-like distribution and the #J
The siit pressure is reduced and the dielectric strength against impact voltage as a disk winding is increased. However, as shown in Figure 2, although electrically two conductors are used in parallel, a disk coil has a configuration in which four conductors are wound in parallel. Therefore, there is a problem that manufacturing the disk winding becomes more difficult. Furthermore, since there is a connection part 32 where the number of turns increases from bottom to top, continuous winding is adopted in which the entire disk winding is wound continuously from top to bottom in the figure, eliminating the welded connection point of the conductor. However, there is a problem in that the conductors of both the disc coils 11 and 12 must be connected by welding at the connecting portion 32. The presence of welded connections not only increases the number of manufacturing steps due to the need for welding operations, but also poses an important problem in that the reliability of the welds affects the reliability of the entire transformer.

This invention solves these problems, and allows the number of conductors in parallel when winding a disc winding to be the same as the number of electrical parallels, and allows continuous winding without the need for welded connections of the conductors. The purpose is to provide a high series capacitance disk winding.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a central disk winding formed by stacking a predetermined number of stages of disk coils each having an even number of parallel conductors and connecting them in series; a lower end disc winding consisting of parallel conductors of half the number of the central disc winding, which are coaxially disposed at the upper end in the axial direction of the central disc winding;
A lower end disc winding is provided at the lower end of the central disc winding and has the same number of parallel windings and turns as the lower end disc winding,
The upper end of one half of the parallel conductor of the central disc winding is connected to the terminal end of the i winding in the upper end, and the lower end of the remaining one half of the parallel conductor of the central disc winding is connected to the lower end of the parallel conductor of the central disc winding. Connect to the starting end of the plate winding, connect the starting end of the lower end disc winding, the lower end disc winding of the central disc winding and the remaining parallel conductors that are not connected to the upper terminal, and connect the lower end disc winding to the upper terminal, The remaining parallel conductors that are not connected to the end of the winding and the lower end disk winding of the central disk S wire are connected to the lower terminal.

[Effect]

In the configuration of this invention, there is a central disc winding formed by stacking a predetermined number of stages of disc coils each having an even number of parallel conductors and connecting them in series; A lower end disc winding is provided at the lower end of the central disc winding, and the number of parallel conductors and the number of turns are equal to each other at the lower end. It consists of a disk winding and the same lower end disk winding, the upper end of one half of the parallel conductor of the central disk winding is connected to the terminal end of the lower end disk winding, and the central section Vi, Connect the lower end of the remaining half of the parallel conductor of the S wire to the starting end of the lower end disc winding, and connect the starting end of the lower end disc winding to the lower end disc winding of the central disc winding. The remaining parallel conductors that are not connected to the lower end disk winding are connected to the upper terminal, and the remaining parallel conductors that are not connected to the lower end disk winding of the lower end disk winding and the center disk winding are connected to the lower terminal. As a result, a pair of parallel conductors are connected from the upper terminal to the parallel conductors of the lower end disk winding and half of the center disk winding, and are connected to the lower terminal, and Two sets of parallel conductors are formed, one set being connected to the parallel conductors of the remaining half of the disk winding, the other being connected to the lower end disk winding and connected to the top terminal.

Since the number of turns of the lower end disc winding and the lower end disc winding are the same, the number of turns of these 2 & [I parallel conductors is equal, and the two sets of conductors are The windings are arranged adjacent to each other, and there is a difference in the number of windings corresponding to the number of windings of the upper and lower end disc windings. The electrostatic energy increases in proportion to the square of the difference in the number of turns, and the series capacitance as the equivalent capacitance increases, so the high series capacitance disc winding suppresses potential oscillations when an impact voltage is applied. becomes. The central disc winding is composed of ordinary disc windings with an even number of parallel conductors, so the number of parallel conductors during winding work can be the same as the number of electrical parallel conductors, making winding work easy. This enables continuous winding of the conductor without the welded joints used in ordinary disc windings.

〔Example〕

The present invention will be explained below based on examples. FIG. 1 is a conductor arrangement diagram which is also a schematic diagram of a winding cross section of a high series capacitance disc winding showing an embodiment of the present invention.

In this figure, the reference numbers for the conductors are the same as in Figure 2, consisting of numerical values representing the number of turns from the upper terminal 22 and letters c and d to distinguish between conductors connected in series, and conductors with the same letter are electrically This indicates that the conductor is connected to one conductor.

Two conductors 1c branch from the upper terminal 22.

1d is connected, the conductor IC enters the outer diameter side of the disc coil 15, and the conductor 1d enters the inner diameter side of the disc coil 16. The conductor 1c reaches the inner diameter side of the disc coil 15, becomes a conductor 8c, and is connected to the conductor 9c of the disc coil 16. The conductors 9c and ld are connected together on the inner diameter side of this disc coil 16, and from then on, until just before being connected to the disc coil 21, the connecting portion 3 on the outer diameter side is
The 0-disk coil 21 has a connection method opposite to that of the disk coil 15, in which adjacent disk coils are connected in series at the connecting portion 35 on the inner diameter side.Finally, the two parallel conductors are connected by the lower terminal 23. electrically connected together. In this figure, the lower half of the high series capacitance disc winding is arranged symmetrically with the upper half, so reference numbers for the conductors of the lower disc coils, such as disc coils 19, 20, and 21, are omitted. As is clear from a certain figure, all the connection parts 34 and 35 have a configuration in which two conductors are connected, and this is similar to a normal disk winding, and this high series capacitance disk winding The entire wire can be manufactured as a continuous-wound disc S wire without any welded connections between conductors other than connections with upper and lower terminals.

The disc coils 15 and 21 have two conductors connected to upper and lower terminals 22 and 23 separately from the inner diameter side and the outer diameter side, respectively, and the other disc coils 16 to 20 are structurally connected in the radial direction. This is the most basic disk winding consisting of two parallel conductors stacked on top of each other. However, the feature of the central disc winding 100 composed of the central disc coils 16 to 20 is that, for example, the conductors 1d and 90 on the inner diameter side of the disc coil 16 have 8 turns, and the adjacent conductor 9c There is a difference in the number of turns of 7 turns at 2d.

In this way, all the conductors of the central winding 100 have a difference in the number of turns of 7 or 8 turns. This means that the connection method increases the difference in the number of turns between adjacent conductors in order to increase the series capacitance mentioned above, and the number of turns on the central disk is 10.
It is shown that a series capacitance of 0 realizes a high series capacitance as in the prior art. When calculating the electrostatic energy ratio for a 1° group of disk coils consisting of disk coils 16 and 17 in the same way as the example in Figure 2, there are 6 areas with a 7-turn difference, and 6 areas with an 8-turn difference. There are 8 parts, so 7 squared times 6 is 294.8 squared times 8 is 512, totaling 806.0 In the case of a normal disk coil,
As mentioned above, this value is 6, so the central part volume! %1
It can be seen that R100 has about 100 times the electrostatic energy. However, while this value in the case of Fig. 2 was 82, the reason why it is about 10 times this in Fig. 1 is due to the relationship with the number of turns of the disc coil that was applied, and the height in Fig. 2. This result was obtained from the configuration adopted as a series capacitive disk winding, and even in the case of the prior art shown in Fig. 2, there is a connection method that increases the electrostatic energy value higher than that shown in Fig. 2. The fact that the electrostatic energy value in FIG. 1 is larger than that in FIG. 2 described above is not necessarily an effect of this invention.

In Fig. 1, the upper and lower end disc windings 15, 21 are composed of only one disc coil, but they can be formed of two disc coils, which are similar to the disc coils 11 and 12 in Fig. 2. Adopting the normal high series capacitance disk winding connection method using a single conductor,
It is also possible to adopt a method in which the conductor 1b starts from the third disc coil from the top. Further, the number of parallel high series capacitance disc windings is not limited to 2, but the present invention can be applied as long as it is an even number that is a multiple of 2.

In this case, the upper and lower end disc windings 15 and 21 are configured with half the number of parallel windings, and are connected to half the number of central disc windings, thereby achieving the invention. can achieve the same effect.

It is not necessarily necessary that the lower end disc winding and the lower end disc winding have the same configuration; as long as the number of parallel conductors and the number of turns are the same,
It is not necessary to adopt exactly the same configuration when applying this invention. For example, if the upper terminal 22 is on the line side of a star-shaped connection and the lower terminal 23 is on the neutral point side, the impulse voltage is always applied from the line side. Since a large voltage is applied to the application side, the lower end disc winding 15 is replaced by the lower end disc winding 21.
In some cases, it may be necessary to adopt a winding structure with superior impact voltage resistance compared to the conventional windings.

〔Effect of the invention〕

As described above, the present invention includes a central disk winding having an even number of parallel conductors, a lower end disk winding having one half of the parallel conductors provided at the upper end of the central disk winding; A high series capacitance disk winding is constituted by the lower end disk winding provided at the lower end of the central disk winding in which the number of parallel windings and the number of turns are the same as the lower end disk winding. Then, the upper end of one half of the parallel conductor of the central disc winding is connected to the terminal end of the lower end disc winding to form a set of parallel conductors, and both ends of the parallel conductor are connected to the upper terminal and the lower terminal. do. Also, connect the lower ends of the remaining 1/2 parallel conductors of the central disc winding to the starting ends of the lower end disc windings to form another 111 parallel conductors, and connect both ends to the upper and lower terminals. Connecting. The two sets of parallel conductors formed in this way have the same number of turns since the lower end disk winding and the lower end disk winding have the same number of turns, and the inside of the center disk winding has the same number of turns. These 2&[l conductors are arranged adjacent to each other, and a difference in the number of turns corresponding to the number of turns of the upper and lower end disc windings occurs between the adjacent conductors. Since electrostatic energy increases in proportion to the square of the difference in the number of turns, and the series capacitance as the equivalent capacitance increases, high series capacitance disc winding suppresses potential oscillation when an impulse wit pressure is applied. It becomes a line. The central disc winding is composed of ordinary disc windings with an even number of parallel conductors, so the number of parallel conductors during winding work can be the same as the number of electrical parallel conductors, making winding work easy. Therefore, the work time is shortened and the cost of the transformer is reduced. Furthermore, since continuous winding, which is used in ordinary disk windings, is possible, there are no welded connection points other than those where the upper and lower terminals connect the conductor of the high series capacity disk winding. As a result, the possibility of accidents due to poor welding is reduced, which also has the effect of contributing to improved reliability as a transformer.

[Brief explanation of the drawing]

FIG. 1 is a conductor arrangement diagram showing an embodiment of the present invention, and FIG. 2 is a conductor arrangement diagram showing an example of the prior art. 15... Disc coil (lower end disc winding), 16.17
．． 1B, 19.20... Disc coil, 100... Center disc winding, 21... Disc coil (lower disc winding), 22... Upper terminal, 23... Lower part terminal.

Claims (1)

[Claims] 1) A central disc winding formed by stacking a predetermined number of stages of disc coils each consisting of an even number of parallel conductors and connecting them in series; an upper end disc winding consisting of parallel conductors with half the number of parallel conductors of the central disc winding; and a lower end of the central disc winding, the number of parallel conductors and the number of turns being equal to the upper end disc winding. The upper end of one half of the parallel conductor of the central disc winding is connected to the terminal end of the upper end disc winding, and the remaining part of the central disc winding is connected to the terminal end of the upper end disc winding. Connect the lower end of the 1/2 parallel conductor to the starting end of the lower end disc winding, and connect the remaining parallel conductors that are not connected to the starting end of the upper end disc winding and the upper end disc winding of the middle disc winding. The conductor is connected to the upper terminal, and the remaining parallel conductor that is not connected to the terminal end of the lower end disc winding and the lower end disc winding of the central disc winding is connected to the lower terminal. Series capacitive disc winding.