JPS64885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for an electrical conductor coated with insulation, and more particularly to a support device for supporting an electrical conductor coated with insulation using an insulator.

Conventionally, there has been a support device of this type as shown in FIG. The figure shows an example of a support device for an insulated electrical conductor in a three-phase line.
An insulated electrical conductor 3 formed by applying a suitable insulating coating 2 to an electrical conductor 1 is supported by being sandwiched between a pair of support insulating plates 4 having grooves 4a. Reference numeral 5 indicates a mounting hole for attaching the supporting insulating plate 4 to an electrically grounded metal structure, etc., and 6 indicates a gap formed at the contact portion between the insulating coated electric conductor 3 and the supporting insulating plate 4. Such a support device for an insulated electrical conductor can provide insulation to the metal duct by attaching the insulated electrical conductor 3 to the electrically grounded metal duct using the mounting hole 5 of the support insulating plate 4. Both the insulating coating 2 and the support insulating plate 4 are double-layered to improve safety.

However, in the conventional supporting device as described above, if the surface resistance of the supporting insulating plate 4 decreases due to dust adhering to the supporting insulating plate 4 or dew condensation, etc., the insulated electrical conductor 3 and the supporting insulating A discharge occurs at the contact portion with the plate 4, and a large current discharge occurs on the surface of the insulation coating 2 of the insulation coating electrical conductor 3.
Since the insulating material deteriorates due to such discharge, there is a problem in continuing to use this support device over a long period of time. Furthermore, if the supporting insulating plate 4 and the insulating coating 2 in the vicinity of the supporting insulating plate 4 are significantly contaminated, a large electric discharge may occur, causing the insulating coating 2 to become carbonized or burnt out.

The present invention has been made in view of the above points, and an object thereof is to provide a support device for an insulated electrical conductor that suppresses the discharge current of discharge generated on the surface of an insulating coating or prevents the occurrence of discharge. It is something.

In order to achieve the above object, the present invention is characterized in that insulation coating pleats are formed in a portion of the insulation coating of the insulation coating electrical conductor near the supporting insulator.

An embodiment of the present invention will be described below with reference to the drawings. 2 to 4, in a support device that supports an insulated electrical conductor 3 formed by applying an insulating coating 2 to an electrical conductor 1 by sandwiching it between supporting insulating plates 4, a portion of the insulating coating 2 near the supporting insulating plate 4 is shown. Insulation coating pleat 7
It is formed by forming. This insulation coating pleat 7
The number, position, and size of can be selected as appropriate. Further, the insulation coating pleats 7 can be easily formed as follows. One method is to prepare a sleeve made of an insulator in advance to fit onto the insulated electrical conductor 3, fit this sleeve onto the insulated electrical conductor 3, and bond it with an adhesive. Another method is to create the insulated electrical conductor 3 on which the insulated pleats 7 are formed by casting or molding.

Next, the effects will be explained.

FIG. 3 shows a case in which the support insulating plate 4 and the insulating coating 2 in the vicinity of the supporting insulating plate 4 and the insulating coating 2 in the vicinity of the supporting device as shown in FIG. It is connected to the power supply 8. 9
indicates electrical ground. Dirty part 1 of insulation coating 2
0 and 11 have a lower surface resistance, and in between, there is a portion 13 that is not contaminated and is kept clean and has a high surface resistance. It is assumed that the support insulating plate 4 also has a soiled portion 12. In addition, an uncontaminated portion of the insulation coating 2 is indicated by 14. The lengths of the soiled parts 10, 11 and the part 13 are respectively l ₁ ,
Let l ₂ and l _g .

FIG. 4 is a diagram in which FIG. 3 is replaced with a simple electrical equivalent circuit. In the figure, 15 indicates a gap directly above the uncontaminated portion 13,
5, a discharge occurs. Cg is the capacitance of the air gap 15,
Rg is the surface resistance of the portion 13, and Ca and Cb are the capacitance _R1 of the insulating coating corresponding to each contaminated portion, assuming that the surface resistance of the contaminated portions 11 and 10 is sufficiently small. surface resistance, Cc
is the capacitance corresponding to part 14, Cs is the ground point 9
represents the stray capacitance at the contaminated area 10
The point of contact between and the supporting insulating plate 4 is shown. Note that FIG. 4 shows the supporting insulating plate 4 for ease of explanation below.
The surface resistance of the soiled portion 12 is shown for a sufficiently small case. In FIG. 4, the discharge in the uncontaminated portion 13 is caused by dividing the voltage applied by the power source 8 according to the ratio of the combined impedance of Ca, Rg, and Cg, and the voltage being distributed to the portion 13. When the voltage reaches the dielectric breakdown voltage of the air gap 15, a discharge occurs.

Here, when the support device is formed with insulation coating folds 7 as shown in FIG. 2 according to the present invention,
Since the capacitance Ca of the contaminated portion 11 becomes small, the voltage distributed to the portion 13 becomes small, and the externally applied voltage at which discharge occurs in the gap 15 becomes high. The reason why the capacitance Ca of the soiled portion 11 is small is that the soiled portion is divided by the insulation coating pleats 7 .

On the other hand, when discharge occurs in the void 15, the discharge charge Q is equal to the surface resistance ^R1 of the uncontaminated portion 14.
Assuming that is sufficiently large, it can be expressed by the following equation.

Q=(2CcCs/Cc+Cs+Cb)Ca/2CcCs/Cc+Cs+Cb+
Ca+Cgvg...(1) Here, Vg is the dielectric breakdown voltage of the air in the void 15. Generally, the stray capacitance Cs is smaller than Ca, Cb, and Cc, and the length of the contaminated parts 10 and 11
Even if l ₁ and l ₂ become longer, the part 14 that is not contaminated
In many cases, the length of is sufficiently longer than l ₁ and l ₂ . Therefore, the value of (2CcCs/Cc+Cs) in equation (1) can be considered to be constant even if the lengths l ₁ and l ₂ of the soiled portions 10 and 11 change.

FIG. 5 shows the relationship between discharge charge Q and Ca when the value of (2CcCs/Cc+Cs) is constant, and it can be seen that discharge charge Q increases as Ca increases. In the figure, when curves A and B are compared, the capacitance Cb of the insulating coating corresponding to the soiled portion 10 is larger in curve A than in curve B. From the above analysis, the discharge charge Q becomes smaller when Ca and Cb are reduced. From this, by forming the insulation coating folds 7, Ca,
It is easy to see that Cb is small and therefore the discharge charge Q is small. This is because the soiled portion is divided by the insulation coating pleats 7.

In the above explanation, the surface resistance of the contaminated parts 10, 11, and 12 is assumed to be zero, but even if this surface resistance is a finite value, the increase in the discharge generation voltage due to the insulation coating folds 7 and the discharge charge It is easy to see that a reduction in Q can be achieved. Further, the number, position, and dimensions of the insulation coating pleats 7 are not particularly limited, and can be appropriately selected depending on the expected degree of contamination.

As described above, according to the present invention, when the surface of an insulating coated electrical conductor is contaminated, the voltage at which discharge occurs on the surface of the insulating coat is increased to suppress the occurrence of discharge, and even when discharge occurs, the discharge charge is suppressed. Since it is made extremely small, it has the effect of preventing deterioration of the insulation coating.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main part of a conventional device, FIG. 2 is a side view of the main part of an embodiment of the present invention, FIG. 3 is a schematic side view of the main part for explaining the operation, and FIG. FIG. 3 is an electrical equivalent circuit diagram, and FIG. 5 is a characteristic curve diagram for explaining the effect. DESCRIPTION OF SYMBOLS 1... Electric conductor, 2... Insulating coating, 3... Insulating coating electric conductor, 4... Supporting insulating plate, 5... Mounting hole, 7... Insulating coating pleat.

Claims (1)

[Scope of Claims] 1. Insulation made by sandwiching an insulated electrical conductor, which is formed by applying an insulating coating to the entire surface of the electrical conductor, between a pair of opposing support insulating plates having grooves to which the insulated electrical conductor is attached. In a support device for a coated electrical conductor,
Insulating coating pleats are integrally formed in the vicinity of both sides of the supporting insulating plate of the insulating coating to prevent minute partial discharges occurring in the air layer between the supporting insulating plate and the insulating coating. Support device for insulated electrical conductors. 2. The supporting device for an insulated electrical conductor according to claim 1, wherein an insulated sleeve is fitted and bonded to the insulated electrical conductor to form an insulated fold. 3. A supporting device for an insulated electrical conductor according to claim 1, wherein the insulated folds are formed during the production of the insulated electrical conductor. 4. The support device for an insulated electrical conductor according to claim 1, wherein a plurality of insulated folds are formed at appropriate intervals.