JPS63209112A - Multicylinder winding - Google Patents

Abstract

PURPOSE:To make title windings small-sized and improve dielectric strength by inserting electrostatic shields into at least one spot of interlayer end parts to be impressed by voltage of a two layer portion of multicylinder windings for enlarging series electrostatic capacity of the windings. CONSTITUTION:Electrostatic shields 4 are inserted into winding end parts not connected by connecting conductors 3 of the mutually neighboring cylinder windings 2a-2e, that is into the interlayer end parts to be impressed by voltage of a two layer portion. These electrostatic shields wherein conductors 4 are insulation coated 4b, are electrically connected to the respective cylinder windings by potential lines 5 so that their potential may be equal to the high potential part between the neighboring winding layers. Accordingly, even in case of impressed thunder voltage, potential oscillation inside the windings is lowered so as to suppress over-voltage to be generated between the winding layers for preventing dielectric breakdown and reducing an interlayer dielectric size. Thereby, the small-sized and reliable multicylinder windings having high dielectric strength can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to multiple cylindrical windings of a transformer, and more particularly to an interlayer insulation structure that suppresses overvoltage appearing between layers when a lightning surge enters.

(Prior Art) In response to the recent increase in power demand, oil-immersed transformers are becoming increasingly high-voltage and large-capacity, and the overall size of the transformer is also increasing accordingly. However, on the other hand, transportation restrictions and installation location conditions require further downsizing.
Furthermore, in order to provide stable power supply, there is a growing demand for highly reliable transformers that do not cause accidents such as insulation breakdown.

There are various types of transformer windings, but conventionally large transformers generally use disk windings. However, with this disc winding, if lightning voltage enters the transformer from the power transmission system, high voltage may be applied to the part near the input end of the winding, causing dielectric breakdown. In addition, it requires a lot of winding man-hours and is difficult to manufacture. It has the disadvantage that it takes a lot of time. Recently, instead of such a disk winding, the application of a large transformer with multiple cylindrical windings, which has a better initial potential distribution and requires less winding man-hours, has been considered. FIG. 2 shows a schematic configuration of a conventional multiplex cylindrical winding. In FIG.
b...2e is wound multiple times.゛Each cylindrical winding 2a
, 2b...2e have their upper and lower winding ends alternately connected by connecting conductors 3, respectively. ! ! connected in series. Since the voltage of two layers is applied between the layers at the end of each cylindrical winding 2a, 2b...2e that are not connected by the connecting conductor 3, the interlayer insulation dimension d of this part is the interlayer insulation dimension of the opposite end. It's bigger. Further, one end of these cylindrical windings 2a, 2b, . . . , 2e connected in series is used as a U terminal, and the other end is used as a V terminal.

(Problem to be solved by the invention) When lightning voltage enters from the outside in such a multiple cylindrical winding, the input terminal (U
As described above, the multiple cylindrical winding to which a large voltage is applied near the terminal side has a relatively good initial potential distribution, but even so, an excessive voltage is applied to the ends of the winding. In order to prevent dielectric breakdown due to excessive voltage application, it is possible to further increase the insulation dimension d between the eyebrows in Figure 2, but increasing this interlayer dimension increases the winding diameter and increases the size of the entire transformer. This is an undesirable result.

In view of the above points, it is an object of the present invention to obtain a multi-layered cylindrical winding that is more compact, has high dielectric strength, and has high reliability.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention inserts an electrostatic shield in at least one place at the end of the layer where the voltage of the poor layer of the multiple cylindrical winding is applied. The series capacitance of the winding is increased.

(Function) With this configuration, even when lightning voltage is applied, the potential oscillation within the winding is reduced, thereby suppressing overvoltage generated between the winding layers, preventing dielectric breakdown, and reducing the interlayer insulation dimension.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In Fig. 1, parts that are the same as the conventional one are denoted by the same reference numerals. In Fig. 0, 1 is an insulating cylinder provided around the iron core, and cylindrical windings 2a, 2b, . . . , 2e are wound multiple times around this insulating cylinder 1. It's spinning. The cylindrical windings 2a, 2b, . . . , 2e are electrically connected in series by having their winding ends alternately connected at their upper and lower ends by connecting conductors 3. Since the voltage of two layers is applied between the layers at the ends of the windings that are not connected by the connection conductor 3 of each adjacent cylindrical winding 2a, 2b...2e, the interlayer insulation dimension d of the second part is opposite. It is larger than the interlayer insulation dimension at the end. Furthermore, one end of these cylindrical windings 2a, 2b, . . . , 2e connected in series is used as a U terminal, and the other end is used as a V terminal. In the multiple cylindrical windings according to the present invention, the cylindrical windings 2a, 2 which are adjacent to each other
An electrostatic shield 4 is inserted at the ends of the windings that are not insulated by the connecting conductors 3 of b...2e, that is, at the interlayer ends where voltages for two layers are applied. This electrostatic shield 4 has an insulating coating 4b applied to a conductor 4a, and is electrically connected to each cylindrical winding by a potential wire 5 so that the potential thereof is the same as the high potential part between adjacent winding layers. . In addition, the length Q of the electrostatic shield 4 is ≦1/2H, where the height of the winding is H,
Rather than covering the entire height of the winding with one electrostatic shield.

According to the multiple cylindrical winding of the present invention configured in this way,
For example, when a lightning potential is externally applied to the U terminal, the voltage within the winding causes potential oscillations depending on the value determined by the ground capacitance of the winding and the series capacitance. In this case, the larger the series capacitance of the winding, the less vibration and the occurrence of local overvoltage.6 In the present invention, since the electrostatic shield 4 is inserted between the layers of the winding, the series connection of the winding The capacitance is increased, the voltage generated between the layers is reduced compared to the conventional method, and the dimensions of the interlayer insulation can be reduced. In addition, this electrostatic shield 4 does not require a current to flow through the conductor 4a, so it can be constructed of a foil-like conductor, for example, and the expansion of the interlayer insulation dimension due to the attachment of this electrostatic shield 4 is ignored. be able to.

In the above embodiment, the case where the potential of the shield 4 was set to be the same as the winding potential was explained. However, if the electrostatic shield 4 is floating without being connected to any part of the winding, the electrostatic shield 4 is connected between the layers. , and the same action and effect as in the embodiment described above is produced. Further, the electrostatic shield does not need to be inserted between all the layers of the winding, but may be inserted between some layers, such as the layer near the high voltage terminal, for example.

〔Effect of the invention〕

As described above, according to the present invention, cylindrical windings are wound in multiple layers around an insulating cylinder provided around the iron core, and the winding ends of the cylindrical windings are connected alternately at the top and bottom so that they are electrically connected in series. In multiple cylindrical windings connected to

Since an electrostatic shield is inserted between at least one layer of the cylindrical winding, it is possible to obtain a multi-layered cylindrical winding which is more compact and has high dielectric strength and reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a multiple cylindrical winding according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a conventional multiple cylindrical winding. 1... Insulating tubes 2a, 2b, 2c, 2d, 2e - cylindrical winding 3... Connection conductor 4... Electrostatic shield 4a... Conductor
4b... Insulating coating 7... Potential line agent Patent attorney Noriyuki Chika Yudo Hirofumi Mitsumata Figure 1■ Figure 2

Claims (3)

[Claims] (1) Multiple cylindrical windings are wound around an insulating cylinder provided around the core, and the upper and lower winding ends of the cylindrical windings are connected alternately and electrically connected in series. A multiple cylindrical winding, characterized in that an electrostatic shield is inserted between at least one layer of the cylindrical winding. (2) The multiple cylindrical winding according to claim 1, wherein the electrostatic shield has the same potential as the winding. (3) The multiple cylindrical winding according to claim 1, wherein the electrostatic shield has an intermediate potential between the winding layers.