JPS609332B2 - Submerged oil lead extraction device for induction electric equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high voltage submerged oil lead extraction device for a power conductor such as a transformer.

Conventionally, when the connection lead connected from the coil outlet to the lower terminal of the bushing is exposed to high voltage, especially ultra-high voltage, the surface of the center conductor is coated with insulating paper, etc., and at the same time several wires are placed on the outside. By arranging the insulating cylinder in a cylindrical shape and subdividing the adjacent oil pipes to prevent excessive electric field concentration on the lead insulating surface, we take advantage of the characteristics of improving oil resistance pressure and stabilizing the oil pipes by subdividing the oil pipes. was.

In this way, it is possible to sufficiently control the electric field on the high voltage side by adopting a barrier insulation structure, but it is possible to control the electric field sufficiently by adopting a barrier insulation structure. The electric field is not necessarily as high as that on the high voltage electrode side, but due to its structure, sufficient insulation cannot be applied. Therefore, even an abnormally low electric field may cause dielectric breakdown due to defects on the surface of the counter electrode, such as unevenness, air bubbles trapped by coating, etc., or the presence of dust or foreign matter, and the variation with respect to the average breakdown electric field is large. Particularly in the case of lead connection structures using ducts, which are installed on-site during hemming work, it is difficult to expect them to be as complete as they would be in a factory, even with sufficient dust control, and post-assembly verification cannot be performed. For extremely high voltage applications such as 500KV or 1000KV, it is common to avoid structures that require on-site IJ cable connection work as much as possible. However, due to constraints such as transportation conditions, it is not always possible to satisfy this condition, and there is a strong need to connect two or more divided transformers etc. with ducts, and the leads to be connected are also high voltage leads, There are often multiple leads including low voltage leads. The present invention was made to solve these problems, and it allows high and low voltage leads to be connected in the same duct, allows the characteristics verified in the factory to be reproduced on site, and has a compact insulation structure. The object of the present invention is to provide a submerged oil 1'' cord extraction device having the following characteristics. An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a high voltage lead, 11 is an insulating coating provided on its outer periphery, 2 is a low voltage lead electrode provided in a coaxial cylindrical shape with the high voltage lead 1 as the center, and 21 and 22 are provided on the inner and outer peripheries of each. 3 is a shield electrode provided on the outside of the low voltage lead electrode 2 in a double concentric cylindrical shape with the high and low voltage leads; 31 and 32 are insulators integrally formed on the inner and outer peripheries of the shield electrode 3; 41 to 43 are cylindrical insulating barriers placed through appropriate oil passage spacing pieces 5 to subdivide the oil passage between the high voltage lead electrode and the low voltage lead electrode 2, and 61 to 63 are also low voltage lead electrodes. a cylindrical insulating barrier, 8 arranged via a suitable oil passage spacing piece 7 to subdivide the oil passage between 2 and the shield electrode 3;
9 is a support for fixing the lead, and 9 is an oil duct for connecting the lead. The shield electrode 3 is connected to the duct 9 through the ground lead 101 at an appropriate location and is grounded. According to this structure,
Since the low voltage lead electrode 2 between the high voltage lead 1 and the outer shield electrode 3 shields the high voltage lead 1, it is natural that the insulation between the high voltage lead 1 and the low voltage lead electrode 2 is between high and low voltage. The insulation between the low voltage lead electrode 2 and the shield electrode 3 is literally just insulation against a resistance voltage.

In other words, when passing the high voltage lead through the cylindrical shield electrode 3, the high voltage 1''-do and the shield electrode 3
There must be a position where the potential on the cylindrical surface of a certain radius in the insulating layer between the two ends is the same potential as the low voltage lead electrode 2, and if the low voltage lead electrode 2 is placed at this position, the shield electrode 3
This means that two high and low pressure IJ leads can be passed through in almost the same space as when only the high voltage lead is passed through, and there is no need to provide a new duct for connecting the low voltage IJ leads. Furthermore, the insulation barriers 41 to 43 between the high voltage lead 1 and the low voltage IJ-domain electrode 2 and the insulation barriers 61 to 63 between the low voltage lead electrode 2 and the shield electrode 3 are coaxial cylinders, so that the electric field of each part is coaxial. It can be easily obtained by calculation, and the experimental formula for the electric field of each part and the allowable electric field of the oil pipe in barrier insulation is E=K・d−Q (KV/rib) [where d is the size of the oil pipe (leg), K・Q is a constant] Determine the oil pipe dimensions appropriately. That is, the dimensions of the oil canals are selected to be smaller in the area near the center of the coaxial cylinder where the electric field is concentrated, and to be larger as the area approaches the shield electrode 3, so that the allowance for destruction of each canal is made approximately the same. When such a barrier insulation structure is used, the withstand pressure is improved by dividing the oil pipe, and the variation in breakdown is reduced, so stable insulation properties can be obtained and a compact duct can be constructed. for example,
When dividing the autotransformer that connects the 500KV system and the 27V system, and connecting the 50V lead and the 27V lead using an oil-submerged duct, the size of the conventional duct is 50KV.
What used to require two ducts of approximately 10,000 (object) for the 0KV lead and approximately 6,000 (willow) for the 27 arc V lead can be reduced to one duct of approximately 600◇ (object) according to the present invention. It is possible to connect the 500KV lead and the 27-arc V lead on a tangent line, which not only improves reliability but also simplifies the connection structure and reduces the size and weight of the duct. Furthermore, in the present invention, even when performing duct connection work on site, the insulation structure from the high voltage lead 1 to the shield electrode 3 can be integrated into the I.
By treating it as a J-do, the structure that was assembled and tested at the factory can be assembled and reproduced on site as is, and there is no room for foreign matter to get into the insulation structure system, and even if foreign matter gets into the duct during duct connection work, Even if there is, no voltage is applied between the ground electrode and the duct, so there is no need to worry about insulation.

At the end of the duct 9 in FIG. 1, as shown in FIG. 2, the tip of the shield electrode 3 is widened with an appropriate curvature in a trumpet shape, and the structure is such that it is brought sufficiently close to the duct wall, so that an electric field is generated at the end. Try not to concentrate.

In addition, the end of the low voltage lead electrode 2 is also rounded with an appropriate curvature at a position sufficiently far away from the duct to alleviate the concentration of electric field.
Connect to 3. In addition, although the structure of the low voltage lead electrode 2 and the shield electrode 3 is explained as being cylindrical in Fig. 1, in order to facilitate assembly, the low voltage A structure in which the lead electrodes 2c, 2b and shield electrodes 3a, 3b are butted against each other, or a structure in which they fit together as shown in FIGS. 4a and 4b may be used.

Materials for the shield electrode 3 include metal plates, thin metal strips,
Alternatively, as in the case of general shields, metal strips knitted into a cloth-like shape, metal foil, metal tape, insulating paper with metal vapor-deposited, semiconductors, etc. can be used.

As explained above, the present invention has the effect of making the submerged oil lead drawing device more compact and improving its reliability.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an example of the submerged lead pulling device according to the present invention, FIG. 2 is a side sectional view of the end of FIG. 1, FIGS. 3 a, b, and 4 a. , b are the divisions of the low voltage lead electrode and shield electrode used in the present invention, respectively;
FIG. 3 is a schematic diagram showing an embodiment in a combined state. 1...High voltage lead, 11...Insulation coating of high voltage lead, 2
, 2a, 2b...low voltage lead electrode, 21, 22...
Insulation coating of low voltage lead electrode, 3, 3a, 3b... Shield electrode, 41, 42, 43, 61, 62, 63... Insulation barrier, 5, 7... Spacing piece, 8... Lead support, 9.
...Connection duct, 10...Ground IJ-do wire. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A cylindrical low voltage lead electrode is disposed on the outer periphery of a high voltage lead via an insulating layer comprising an oil gap and an insulating barrier, and further outside the high voltage lead is an oil gap and an insulating barrier. A cylindrical shield electrode is arranged through an insulating layer, this shield electrode is connected to a duct arranged outside the shield electrode, and the low voltage lead electrode is connected to a low voltage lead electrode existing between the high voltage lead and the shield electrode. An oil submerged lead extraction device for induction appliances placed at the same potential position. 2. The submerged lead extraction device for an induction electric appliance according to claim 1, wherein the ends of the cylindrical low-voltage lead electrode and the shield electrode are curved outward. 3. The submerged lead extraction device for an induction electric appliance as set forth in claim 1, characterized in that the cylindrical low-voltage lead electrode and the shield electrode are combined with electrodes divided into semi-cylindrical shapes.