JPS62163506A - Insulating spacer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for improving the insulation reliability of an insulating spacer used for supporting and fixing a high voltage conductor in a metal container of a closed structure filled with an insulating gas. It is something.

[Technical background of the invention and its problems]

In substations, high-voltage conductors are insulated from surrounding grounded metal containers by high-pressure insulating gas such as SFG gas on busbars connecting transformers and gas-insulated switchgear and between substations. Gas-insulated conduit busbars began to be used.

This gas-insulated conduit bus is a single-phase conduit bus constructed by housing a single high-voltage conductor in a grounded metal container.

There is a three-phase pipeline busbar that houses three high-voltage conductors.

A typical insulating spacer used in such a gas insulated pipeline busbar is shown in FIG. The insulating spacer in FIG. 3 is constructed as follows.

That is, a high voltage conductor 2 is disposed in a sealed metal container 1, and a boss-shaped insulating spacer 3 is used for insulating support thereof. Note: The insulating spacer 3 is provided with high voltage rfA4° and low voltage electrodes 5 at both ends thereof. Furthermore, high voltage shields 6 are provided at both ends of the high voltage electrode 4 in the axial direction to alleviate the electric field.

Note that the metal container is filled with SF and gas 7.

By the way, in the conventional gas-insulated pipeline busbar configured as shown in FIG. 3, the surface of the high-voltage shield 6 is finished by ordinary machining due to cost and other reasons, and its roughness is about 20 to 50 ρ. .

However, in recent years, as gas-insulated pipeline busbars have become more compact and the electric field strength has become relatively high, the issue of the insulation strength of the insulating spacer against polarity reversal voltage, which has rarely been a problem in the past, has arisen. Ta. That is, since the high-voltage shield 6 is subjected to a high electric field, electrons are emitted by field emission from the microprotrusions on the surface, and these electrons attach to gas molecules and become negative ions. These ions drift in the SF and gas 7 in the direction of the applied electric field, and finally accumulate on the surface of the insulating spacer 3. Due to this accumulated charge, the original electric field distribution is distorted, and the insulating spacer 3 becomes flooded due to an unexpectedly low voltage.

Such a phenomenon is particularly likely to occur when the polarity of the voltage is reversed.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide an insulating spacer with high insulation reliability.

[Summary of the invention]

The insulating spacer according to the present invention is characterized in that an insulating film is applied to the outer surface of the high-voltage shield attached to the high-voltage side of the spacer, thereby significantly suppressing field emission from this part.

[Embodiments of the invention]

Examples according to the present invention will be described below.

FIG. 1 is a sectional view showing only the high voltage portion of a post-shaped insulating spacer according to the present invention. That is, in the post spacer 1, a pipe 3 with male threads cut at both ends is fitted into a support tube 2, and a ring 4 having a tapered portion and a slit in the radial direction is attached to both ends of the pipe 3. In this state, the post spacer 1 is fixed to the conductor 6 by screwing a cylindrical high-voltage shield 5 having a female thread that engages with the pipe 3 from both ends. Furthermore, in the present invention, the pipe 3 on the high voltage conductor 6
A synthetic resin pipe 7 made of a material having lower hardness than the metal material of the high voltage conductor 6, such as polymer materials such as Teflon and epoxy resin, is provided at the portion where the high voltage shield 5 slides. A plurality of holes are made in this synthetic resin pipe 7, and a handling spring 8 is inserted into these holes to adjust the potential of the support tube 2, pipe 3, and high voltage conductor 6 integrally cast into the spacer 1. They are kept at the same potential.

Furthermore, on the outer surface (portion A) of the high voltage shield 5,
An epoxy paint film or an oxide film is formed by alumite treatment.

In the post-type insulating spacer according to the present invention configured as described above, the minute protrusions on the outer surface of the high-voltage shield 5, which generate the maximum electric field, are covered with an insulating film, which is necessary for electrons to jump out from this surface by field emission. The voltage level is significantly higher than that in the conventional case where the roughness is about 20 to 50 μm. In addition, in this embodiment, by fitting the synthetic resin pipe 7 between the metal pipe 3 and the high voltage conductor 6, when the spacer 1 is slid over the high voltage conductor 6, the metals do not come into contact with each other. , no metal dust is generated. Note that this synthetic resin pipe 7 does not require much mechanical strength, so even if it is thin, the cost will not increase.

As described above, in the post-shaped spacer shown in this embodiment, by applying an insulating film to the high-voltage shield 5, which generally has the highest electric field, the minute protrusions on the surface are masked, and the electric field emission from this part is suppressed. ing. Furthermore, spacer 1
The design is designed to prevent the generation of minute metal dust when sliding and assembling. Therefore, field emission from these microparticles adhering to the surface of the high voltage shield 5 can also be eliminated.

Therefore, the effect of being able to prevent a drop in the creeping floodover voltage caused by the charging of the post spacer 1 due to electrons emitted from the high voltage shield 5 is remarkable, especially with respect to the polarity reversal voltage. For example, FIG. 2 shows the floodover voltage due to polarity reversal voltage when the high voltage shield 5 has a conventional roughness of 30 μm and when it is coated with an insulating film as in the present example, and the floodover voltage due to unipolar voltage. The comparison was made with the value set at 1.0. It can thus be seen that when a high voltage shield coated with an insulating film is used as in the ninth embodiment, the effect of pre-charging before reversal can be virtually ignored.

In addition, in FIG. 1 showing this embodiment, the outer surface of the high-voltage shield 5 is coated with an insulating coating made of epoxy paint or alumite treatment, but instead of this, the surface of the high-voltage shield processed with a normal grinder is coated with an insulating coating. Of course, the same effect can be obtained even if the insulating film is formed by other means.

〔Effect of the invention〕

As described above, according to the present invention, an insulating film is formed on the surface of the high voltage shield to mask minute protrusions on the surface, and furthermore, when the spacer slides on the high voltage conductor, minute metal protrusions are formed on the surface of the high voltage shield. The dust-free structure prevents fine particles from adhering to the high-pressure shield. Therefore, it is possible to prevent a decrease in floodover caused by charging of the post spacer due to field emission from the high voltage shield, and it is possible to provide a highly reliable post-shaped insulating spacer.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the insulating spacer according to the present invention, FIG. 2 is a diagram showing the relationship between surface roughness and floodover voltage, and FIG. 3 is a conventional insulating spacer 3...pipe.
4...Ring 5...High pressure shield
6...High voltage conductor 7...Synthetic resin pipe 8...
・Plant spring agent Patent attorney Nori Chika Yudo Hirofumi Mitsumata Figure 1 Figure 2

Claims (4)

[Claims] (1) An insulating spacer used in gas insulated equipment to insulate and support a high voltage conductor in a grounded metal container, characterized in that an insulating film is applied to the high voltage shield surface of the insulating spacer. (2) The insulating spacer according to claim 1, wherein the insulating spacer is a post-shaped spacer used in single-phase gas insulated equipment. (3) The insulating spacer according to claim 1, wherein the insulating spacer is a post-type spacer for use in three-phase one-time gas insulated equipment. (4) The insulating spacer according to claim 1, wherein the insulating film is formed by alumite treatment.