JPH019231Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an improvement in an insulating spacer placed in an unequal electric field as an interface between two media.

[Conventional technology and its problems]

FIG. 1 shows an example of a conventionally used insulating spacer in a cross section along the length of an internal conductor.

In the figure, 1 is the internal conductor (high voltage part),
2 is an insulating plate (spacer) that supports the inner conductor 1, and 3 is an outer conductor.

In this case, if an electric current is applied between the internal conductors, a larger electric field strength will be generated along the surface of the insulating spacer as it is closer to the internal conductor.

Further, FIG. 2 shows an example of another conventionally used insulating spacer as a cross section of an internal conductor.

In the figure, 4 is the internal conductor (high voltage part),
6 is an insulator, 5 is a metal ring, and 7 is an external conductor. An insulating spacer is formed by stacking the insulator 6 and the metal ring 5 in multiple layers.

In this case, even if the metal ring 5 is inserted and the creeping surface is divided into multiple layers, as shown in the figure, it is for equal electric field coordination and the distance between the layers is constant.

Incidentally, the creepage breakdown electric field strength E _B generally depends on the creepage length l, and as l increases, E _B tends to decrease. For example, it is said that the short pulse creepage breakdown electric field strength E _B in vacuum has a relationship of approximately E _B ∝1/√l. Therefore, as shown in FIG. 1, a single insulating plate 2 has a long creepage length and a low withstand voltage.

On the other hand, as shown in Fig. 2, if a metal ring 5 is inserted to divide the entire creeping surface into multiple small creeping layers, the withstand voltage will be higher than that shown in Fig. 1, but if the distance between the layers is constant, the uneven electric field will When used at high temperatures, the safety factor SF (breakdown electric field strength/actual electric field strength) differs for each layer, and the design is not optimal.

[Disclosure of invention]

Especially insulating spacers in high dielectric constant media (e.g. water)
When used as an interface between an insulating spacer and a low dielectric constant (e.g. vacuum), the potential distribution in the insulating spacer is determined by the structure on the high dielectric constant side. An insulating spacer with high withstand voltage for a given total creepage length is obtained by inserting multiple layers of metal rings with tapers that connect positions that equally divide the side creepage distance into the insulating spacer. It is.

〔Example〕

FIG. 3 shows an embodiment of the present invention.

The figure shows an insulating spacer with a coaxial structure in a cross section along the length of a conductor.

In the figure, 8 is an internal conductor (to which impulse high voltage etc. is applied), 11 is an external conductor,
10 is an insulator, and 9 is a tapered metal ring.

The inner conductor 8 is supported at the center of a spacer having a coaxial structure in which a plurality of tapered metal rings 9 are embedded in such an insulator 10, and the outer periphery thereof is supported by an outer conductor 11.
By itself, the insulating spacer fills the space on the left side of the figure with a high dielectric constant medium 12, such as pure water,
The space on the right side is used separately as a low dielectric constant medium 13, but since an impulse voltage or the like is applied in such a state, the tapered metal ring 9 is conductor 8
Considering that the closer the electric field strength is to
So that the entire creepage of the insulator 10 has an equipotential difference V,
The tapered metal ring 9 is divided at a plurality of positions, and the end of the tapered metal ring 9 is located at the divided position, and the taper is connected to the position where the creepage distance is divided into equal intervals d on the entire creepage surface on the low dielectric constant medium 13 side. A metal ring 9 is embedded in the insulator 10. Needless to say, in order to arrange such a plurality of tapered metal rings 9, it is necessary to design each tapered metal ring in advance based on the spacer dimensions, potential distribution, etc. It is.

〔effect〕

According to the insulating spacer shown in Fig. 1, an unequal electric field is generated along the surface of the insulating spacer due to the charge applied between the inner and outer conductors, which lowers the creepage breakdown voltage strength. Creepage breakdown voltage strength can be increased by arranging multiple tapered metal rings with equal potential difference on the dielectric constant side, and on the low dielectric constant side, tapered metal rings are arranged with equal potential difference and at equal intervals. Therefore, an insulating spacer with the highest voltage resistance can be obtained for a given total creepage length.

[Brief explanation of the drawing]

FIGS. 1 and 2 are examples of conventional insulating spacers. FIG. 3 shows an embodiment of the present invention. 8...Inner conductor, 9...Metal ring, 10...Insulator, 11...Outer conductor, 12...High dielectric constant side, 13...
Low dielectric constant side.

Claims (1)

[Scope of utility model registration request] An insulating spacer used as an interface between a high-permittivity medium and a low-permittivity medium, with a position that equally divides the potential on the high-permittivity medium side and a position that equally divides the distance between the creeping surface on the low-permittivity medium side. Insulating spacer with tapered ring for tying.