JPS6237522B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high voltage submerged lead connection device for an induction electric appliance such as a transformer.

Conventionally, a divided transformer is installed on-site and these leads are connected in an oil duct.When the voltage reaches high voltage, especially ultra-high voltage, it is necessary to insulate the center conductor surface with insulating paper or the like. At the same time, several insulating cylinders are placed coaxially on the outside, and adjacent oil pipes are subdivided to prevent excessive electric field concentration on the lead insulating surface.By dividing the oil pipe into smaller parts, oil pressure resistance is improved and stability is improved. He used his characteristics to deal with it. By adopting a barrier insulation structure for the center conductor on the high voltage side as described above, it is possible to sufficiently control the electric circuit, but the tank surface or inner structure (e.g. The surface of the iron core, iron core clamping plate, etc.) does not necessarily have a high electric field compared to the high voltage side, but
Due to its structure, sufficient insulation cannot be applied. Therefore, even if the counter electrode is a bare electrode or an insulating barrier is applied, it is difficult to attach it closely to the electrode, so defects on the counter electrode surface such as unevenness, air bubbles trapped by paint, dirt, foreign matter, etc. Due to their presence, dielectric breakdown often occurs even at abnormally low electric fields, and there is a large variation in the average breakdown electric field. Particularly in the case of lead connection structures using oil ducts that are installed on-site during installation work, even if sufficient dust control is performed, it is difficult to expect the same level of perfection as in the factory, and post-assembly verification is not possible. or
At extremely high voltages such as 1000KV, it is common to avoid structures that require on-site lead connection work as much as possible. However, it is not always possible to satisfy this condition due to restrictions such as transportation conditions, and it is highly necessary to connect two or more divided transformers and the like through oil ducts.

The present invention was made to solve these problems, and it is possible to reproduce the characteristics verified in the factory as is on site, and at the same time, it has a compact insulation structure against ultra-high voltage and is easy to assemble. The purpose is to provide an oil submerged lead connection device for electrical appliances.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a lead core wire, 2 is an insulating coating provided on its outer periphery, and 31 to 33 are cylinders disposed concentrically on the outer periphery of the lead core wire 1 via a suitable oil pipe spacing 5. 4 is an insulation barrier 33
, 41 and 42 are insulators formed integrally with the inner and outer peripheries of the shield electrode 4, 6 is a support for fixing the leads, and 10 is an oil duct for connecting the leads. The shield electrode 4 is connected to the duct 10 through a ground lead 11 at an appropriate location for grounding.

According to this structure, the electrode facing the lead core wire 1 becomes the shield electrode 4, and the shield electrode 4
Since the inner periphery of the high-voltage electrode, that is, facing the lead core wire 1, is covered with an insulator 41 that is in close contact with the shield electrode 4, slight defects of the counter electrode itself, such as irregularities on the surface, which are observed in the case of a bare electrode, can be avoided. This reduces the damage caused by unexpectedly low electric fields, and improves the damage characteristics caused by variations in the withstand voltage of the oil itself. In addition, the electric field of each part of the insulation barriers 31 to 33 between the shield electrode 4 and the lead core wire 1 is a concentric cylinder, so it can be easily calculated. The oil pipe dimensions are determined appropriately from the empirical formula E = Kd ^- 〓 (KV/mm) (where d is the oil pipe size (mm) K, and α is a constant). In other words, the dimensions of the oil pipes are chosen to be smaller in the area where the electric field is concentrated near the lead core wire 1, which is the high-voltage electrode, and to be made larger as the area approaches the shield electrode 4, so that the allowance for destruction of each oil pipe is approximately the same. An insulating structure with high insulation properties can be obtained.

Furthermore, even if it is possible to suppress defects by tightly pasting an insulating material on the wall surface of the duct 10, which is the ground electrode, as in the past, it is necessary to have an appropriate barrier configuration based on electric field calculations, which is difficult to maintain in the support structure of the high-voltage side electrode. This is difficult from a point of view, and the dimensions of the oil pipe tend to be relatively large near the ground electrode, and the weakest point of the insulation system, including the support structure, is generally determined based on this large oil pipe section. .

On the other hand, in the present invention, the support structure includes the high voltage electrode as an insulating structure system, that is, everything from the lead core wire 1 to the shield electrode 4, as a support member 6.
This has the advantage of separating the support concept from the insulation structure and eliminating the influence of the support structure on the insulation strength, making it possible to provide a highly reliable lead connection device.

Furthermore, in the present invention, when performing duct connection work on-site, the insulation structure from lead core wire 1 to shield electrode 4 is treated as a lead wire, so that the structure assembled and tested at the factory can be used as is on-site. The assembly is reproduced, and there is no room for foreign matter to get into the insulation structure. Even if foreign matter gets into the duct during duct connection work, no voltage will be applied between the ground electrode and the duct, and the insulation will be maintained. There is also the advantage that the above concerns do not arise. In addition, because the entire structure is barrier insulated, the variation in failure in the oil passage is small, just like in the main gear in the coil, and even if the design has the same failure probability as before, it is much more compact due to the improved pressure resistance due to segmentation of the oil passage. The duct can be configured as follows. For example, in the case of a 500KV lead, the conventional duct size required approximately φ1000mm, but according to the present invention, it is possible to reduce the size to approximately φ500mm, which not only improves reliability but also reduces the size and weight of the duct. effective.

At the end of the duct 10 in FIG. 1, the shield electrode 4 is widened with an appropriate curvature as shown in FIG. The tip of the duct 10 is designed to be sufficiently close to the wall of the duct 10.

In addition, although the structure of the shield electrode 4 was described as being cylindrical in the first part for convenience of explanation, when considering actual assembly, it is difficult to make the insulator adhere to the inside of the shield electrode 4 with a cylindrical shape. Core wire 1
If it is bent, there are inconveniences such as not being able to assemble it. Therefore, in the present invention, the semi-cylindrical shield electrodes 4a and 4b divided along the direction of the lead core wire 1 are butted together as shown in FIG. 3, or they are fitted together as shown in FIG. The structure is designed to solve the above problems. It is also possible to make a very long shield electrode by adding several shield electrodes in the same manner in the longitudinal direction and combining them into an integral structure. In addition, as shown in FIGS. 5 and 6, the shield electrode 1
It is also possible to form a branched structure by making 4a and 14b T-shaped.

These shield electrodes 4a, 4b, 14a, 14
As for the material b, metal plates, thin metal strips, threads woven into cloth, metal foils, metal tapes, insulating paper with metal vapor deposited, semiconductors, etc. can be used, as with general shields. It is.

The above description has mainly been about the embodiment inside the duct, but the distance between the lead core wire and the ground electrode can be shortened even if it is applied inside the main body tank in exactly the same way.
Needless to say, it is possible to obtain stable insulation properties that are not affected by the surface condition or shape of the electrode on the ground electrode side.

Further, in the above embodiment, the shield electrode is used as a ground plane, but it is also possible to apply the potential of a surrounding electrode, such as a coil, to the shield to make the insulation between the shield and the target electrode more compact.

In addition, in the above embodiment, a barrier is arranged coaxially around a single-core lead, and a shield electrode is arranged outside of the barrier, but this can be applied to a multi-core lead 1 as shown in Fig. 7. For example, by surrounding the leads 1 arranged in a plane with insulating barriers 31 and 32 and arranging the shield electrode 4 around the outer periphery of the leads 1, as shown in FIG. It becomes possible to place it in

As explained above, according to the present invention, it is possible to improve the reliability of the insulated lead and provide a compact submerged lead connection device.

[Brief explanation of the drawing]

Figure 1 shows one of the submerged lead connection devices according to the present invention.
2 is a side sectional view of FIG. 1, FIGS. 3 and 4 are schematic diagrams showing the state of division and combination of shield electrodes used in the present invention, and FIG. 5 is a front sectional view showing an example.
Figures 6 and 6 are front and side views showing the shape of the shield electrode in the T-shaped joint, Figures 7 and 8.
The figures are front sectional views showing other embodiments of the present invention. 1...Lead core wire, 2...Insulation coating, 31, 3
2, 33...Insulation barrier, 4, 4a, 4b, 1
4a, 14b... Shield electrode, 11... Lead wire for potential fixing.

Claims (1)

[Claims] 1. A cylindrical insulating barrier is arranged around the outer periphery of at least one insulated lead core wire at a predetermined interval, and at least the inner surface is insulated by molding at a predetermined interval around the outer periphery of the insulating barrier. A cylindrical shield electrode provided with a material is provided, and this shield electrode is electrically connected to one of the counter electrodes on the outside thereof, and the end of the cylindrical shield electrode is curved outward, and the shield electrode is The electrode is divided along the axial direction of the lead core wire to form a semi-cylindrical shield electrode, which is combined to form a semi-cylindrical shield electrode, and the lead core wire, insulating barrier, and shield electrode are collectively supported by a support material. Submerged lead connection device for induction electric equipment.