JPS586111A - Fixing of current transformer - Google Patents

Abstract

PURPOSE:To permit rigid and stable fixing of the titled device without applying excessive force by a method wherein unfoamed foamed synthetic resin is filled between a current transformer and a supporter after applying discharge-proof treatment and the foamed synthetic resin is foamed for hardening. CONSTITUTION:A sealing material 12 is applied between a current transformer 1, a bushing 2 and a mounting frame 3 and liquid foamed epoxy resin 11 is injected under unfoaming or insufficient foaming condition. The resin 11 is then, heated up to a proper temperature for foaming and hardening and the current transformer 1 is rigidly fixed by pressing force or adhesive force caused by foaming.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for fixing a current transformer when a through-type current transformer is attached to a support such as a cannula, a cylindrical support, or other support. It is something.

Conventionally, methods for fixing a through-type current transformer and a support include, for example, tightening and fixing using a side plate and bolts, and fixing by press-fitting a spacer into the gap between the current transformer and the support. A well-known method is to fill the gap between the current transformer and the support with a non-foaming synthetic resin and then harden and fix it. FIG. 1 of the accompanying drawings shows an example of a conventional fixing method using a side plate as a bolt.
3 is a mounting frame which is also a support, and the current transformer 1 is combined with the sleeve fixed to the mounting frame 3, and the current transformer 1 is tightened and fixed by the side plates and poles. Circumferential and diametrical movements of the current transformer I are prevented by frictional forces between the sides of the current transformer I, the side plates, and the mounting frame 3. In such a fixing method, since it is necessary to increase the above-mentioned frictional force, it is necessary to increase the clamping force by pol), which causes an excessive force to be applied to the current transformer lK, reducing the insulation performance. Or, alternatively, the metamorphic ratio WA
There is a disadvantage that there is an increased risk of increasing M&.

Next, FIG. 2 shows an example of a conventional method of press-fitting and fixing a spacer, in which a spacer 6 is press-fitted and fixed between the current transformer l and the sleeve 2. A plurality of spacers 4 are normally used. Movement of the current transformer l in the circumferential direction and the axial direction is prevented by the frictional force between the spacer 6 and the inner circumferential surface of the current transformer l and the outer circumferential surface of the sleeve. This method also has the same drawbacks as the method shown in FIG.

Furthermore, FIG. 3 shows an example of a conventional fixing method in which the gap between the current transformer and the support is filled with non-foaming synthetic resin. Synthetic resin is injected into the gap between the two and hardened, and then identified. As the synthetic resin, epoxy resin for casting and polyester resin are often used.

In this method, the current transformer l is fixed in the circumferential and axial directions by adhering the synthetic resin to the current transformer l and the sleeve. However, in general, the synthetic resin has a property that its volume slightly decreases when it hardens, and for this reason, the boundary between the current transformer l and the synthetic resin
If! -Gloss that produced.

The fixing effect is reduced by lowering the adhesive force.

Furthermore, since the thermal expansion coefficients of the current transformer 11, the sleeve 1, and the synthetic resin 7 are different, each expands or contracts differently depending on the temperature change during operation.

This has the disadvantage that separation may occur between the synthetic resin and the current transformer or the sleeve, which may reduce the fixing effect.

Note that in each of the above figures, the symbol t represents a primary conductor.

The present invention eliminates the above-mentioned drawbacks of the conventional fixing method, and provides a current transformer that is strong, stable, and optically fixable without applying excessive force to the current transformer or support. The purpose is to obtain a method for fixing the vessel, and to achieve this purpose, a foamable synthetic resin in an unfoamed or incompletely foamed state is placed between the current transformer and the support. The present invention is characterized in that it has a step of filling the foamed synthetic resin after carrying out outflow prevention measures, and a step of foaming and hardening the filled foamable synthetic resin, thereby fixing it to a support such as a current transformer.

& 1. Foamable synthetic resins have the characteristic of foaming during curing, increasing the volume and decreasing the apparent specific gravity, and having a slight elasticity due to the air bubbles inside after curing. Typical synthetic resins include foamable epoxy resins and foamable urethane resins.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings showing embodiments thereof.

In the reference figure showing the first embodiment, first, a liquid foaming compound @g1t is placed between the current transformer l and the cannula and the mounting frame J.
For example, foamable epoxy resin (cured #KrIL) is coated with a sealant/J to prevent release of the primary material.
Then, a liquid foamable epoxy resin is injected, and then this is further heated to a moderate temperature to foam and harden. Through such process 1i, the foamable epoxy resin 11 decreases in apparent specific gravity due to foaming and increases in volume -X, and this increase brings the variable current lil and the cannula JK into pressure contact, and due to the pressure and adhesive force, It is possible to firmly fix the change It@/. In addition, in response to temperature changes and vibrations after completion, the slight elasticity caused by the air mK creates a stiffening effect, and the foamed epoxy resin and current transformer 7 mm tube are used. There is no risk of peeling etc. in connection with 2. Therefore,
According to the method of the present invention, there is no need to apply excessive force, and it is possible to obtain the effect that stable and firm fixation can be obtained over a long period of time.

Next, in all sections showing the first embodiment, first.

1 example of unfoamed or incompletely foamed foamable synthetic resin that has been solidified and preformed into a sheet shape with the purpose of preventing foamable epoxy resin from flowing out 1 foamable epoxy resin/J
The tube is wound to a specified size, and then a current transformer is connected to the tube, and the tube is heated to a high temperature to foam and harden.

According to this method, the same effects as in the above-mentioned Embodiment 1 can be obtained, and the relationship N between the current transformer 1 and the cannula 1 can be easily maintained evenly, and it is possible to achieve the same effect as in the Embodiment 1. Seal material l
It also has the effect of eliminating the need for coating. In this case, if the support is not circular, it is also possible to fold the support instead of winding it and temporarily fix it to the support.

Furthermore, FIG. 4 showing the Jll embodiment is an embodiment in which the support is located outside the current transformer, and the gap between the current transformer l and the busbar sheath lda, which is the support, is It is filled with a foamable synthetic resin, such as a foamable epoxy resin. The fixing procedure and effect are the same as in the first embodiment shown in the figures. Note that the reference numeral 1 indicates a sealing material.

More Kt. **The second diagram showing the example is another example in which the support is located outside the current transformer, similar to the J example shown in Figure 6, and in this case, , unfoamed or incompletely foamed synthetic resin 1 preformed in a sheet shape around the outer periphery of the current transformer 1, for example, a foamable epoxy resin 1 is wound to a predetermined length, and this is wrapped around the busbar outer cover 74 m as a support. After being inserted into the container and filled, the foam is heated to an appropriate temperature to foam and harden, and the same effect as that of the third embodiment shown in FIG. 3 is obtained. Note that, depending on the shape of the support, it is possible to fill it by folding it into a paper instead of rolling it and temporarily fixing it, as in the case of the fourth embodiment.

As explained above, according to the present invention, it is possible to easily fix a single-through type current transformer and its support without applying an unreasonable load, and 4. it is stable and strong for a long period of time. This has the effect of providing fixation.

[Brief explanation of the drawing]

1 to 3 are vertical sectional views showing examples of various conventional fixing methods, and FIGS. 1 to 3 are longitudinal sectional views showing examples of various conventional fixing methods. 1st. FIG. 7 is a vertical cross-sectional view showing the third and second embodiments. L...Current transformer, K...Support (mantle) %J...Support (
Mounting frame), da... side plate, 3... bolt, 6... spacer, ri... non-foaming synthetic resin, t...-secondary conductor, //, /
J,/! r, /ri...Foamable synthetic resin (foamable epoxy resin), /J, /4...Seal material, l#...Support (
bus bar envelope). Kabuto 5, Place 6, Flood 7

Claims (1)

[Claims] (1) In the case where a through-type current transformer is attached to a support and is used, an unfoamed or incompletely foamed foamable synthetic resin is placed in the gap between the current transformer and the support after measures are taken to prevent leakage. A method for fixing a current transformer comprising the steps of filling and foaming and curing the filled foamable synthetic resin. (j) The foamable synthetic resin in the filling process is in a liquid state, and the outflow prevention treatment is the application of a sealant to at least the support, the current transformer, and the O-separator.
How to fix the current transformer described in iK. 9) The foamable synthetic resin in the filling step 1 is a foamable synthetic resin that has been preformed into a KI receipt shape to prevent leakage, and the filling is performed by passing the sheet-like foamable synthetic resin through a current transformer or The method for fixing a current transformer according to claim 1, which is performed by either winding or temporarily fixing the current transformer around any of the supports.