JPH05845B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an insulator tube for a transformer.

(Prior Art) This type of insulator generally includes a cylindrical porcelain body, an upper cap fixed to the upper end of the porcelain body, and a conductive cap fixed to the lower end of the porcelain body and assembled into the casing of the transformer. A cylindrical part that is inserted into the casing is integrally formed at the lower end of the porcelain body, and the insertion hole formed in the cylindrical part and the porcelain body is provided with a winding of a transformer and a cylindrical part that is inserted into the casing. A conductive rod is loosely inserted to connect the overhead power line to the upper cap.

(Problems to be Solved by the Invention) However, in the insulator tube having the above structure, there is a problem in that, for example, corona discharge occurs from the conductive rod toward the casing of the transformer that is grounded.
This phenomenon is particularly noticeable in the cylindrical portion.

To solve this problem, the diameters of the porcelain main body and the cylindrical part are increased to create a large gap between the outer peripheral surface of the conductive rod and the inner peripheral surface of the cylindrical part, so that corona discharge occurs. Countermeasures can be considered, such as making it difficult for the porcelain body and the cylindrical part to withstand corona discharge by increasing the wall pressure of the porcelain body and the cylindrical part. If the insulator is made larger or the wall thickness is made thicker, the insulator becomes larger and the weight also increases, which is a problem.

The present invention was developed in view of the above circumstances.
The purpose is to provide an insulator tube for a transformer that is small in size but is less likely to cause corona discharge.

(Means for Solving the Problems) The present invention provides a cylindrical porcelain body 1 having an insertion hole 6 for a conductive rod 5 for connecting a winding of a transformer and an overhead wire, and an upper end of the porcelain body 1. An upper cap 3 is fixed to the lower end of the porcelain main body 1, and an electrically conductive lower cap 4 is fixed to the lower end of the porcelain main body 1 and assembled to the casing C of the transformer. It is an insulator tube integrally formed with a cylindrical part 2 which is inserted through the cylindrical part 2, and a semi-conductive glaze P1 having a large resistance is applied to the outer peripheral surface of the cylindrical part 2, and the upper end side of the semi-conductive glaze P1 is attached to the lower part. While electrically connected to the cap 4, the semiconductive glaze P1
A washer 8 is provided to electrically connect the lower end side of the conductive rod 5 to the conductive rod 5, and a conductive coating P2 is provided on the inner peripheral surface of the insertion hole 6, and the lower end of the conductive coating P2 is attached to the washer 8. electrically connected and the conductive coating P
2 is electrically connected to a terminal T of an overhead electric wire attached to the upper cap 3.

(Function) According to the present invention, the potential difference between the conductive rod and the inner peripheral surface of the insertion hole 6 formed in the porcelain body 1 from the cylindrical portion 2 and the outer peripheral surface of the cylindrical portion 2 is very small. Therefore, even if the gap between the conductive rod 5 and the inner peripheral surface of the insertion hole 6 is narrowed, there is almost no possibility that corona discharge will occur.

(Example) The insulator tube for a transformer according to the present invention will be described below according to an example shown in the drawings.

The drawing shows a salt damage-resistant insulator used for high pressure of 20,000 V. Basically, it consists of a porcelain body 1 with a cylindrical part 2 protruding from the lower end, and a porcelain body 1 with a cylindrical part 2 protruding from the lower end. An upper cap 3 made of a conductive material that is fitted and fixed, and a lower cap 4 made of a conductive material that is fitted and fixed above the cylindrical part 2 of the porcelain body 1.
The porcelain body 1 and the cylindrical portion 2 are provided with insertion holes 6 for the conductive rods 5 that connect the windings S1 of the transformer and the overhead wires S2. , a plurality of flanges 7 extending radially outward are formed at predetermined intervals.

As shown in FIGS. 1 and 2, such an insulator tube is constructed by inserting the cylindrical portion 6 into the casing C of the transformer, and inserting the lower cap 4 into the casing C.
At the same time, the terminal T to which the overhead electric wire S2 is connected is bolted to the top of the upper cap 3, and the conductive rod 5 is loosely inserted into the insertion hole 6, and the upper end of the conductive rod 5 is It is screwed onto the terminal T for electrical connection, and the lower end of the conductive rod 5 is connected to the winding S1 of the transformer.
It is used by electrically connecting the ends of the

However, in the above configuration, the porcelain main body 1
At the time of molding, the inner circumferential surface of the insertion hole 6 and the outer circumferential surface of the porcelain main body 1 excluding the fitting portions of the upper and lower caps 3 and 4 (area indicated by arrow X in FIG. 1), and the Semi-conductive glazes P0 and P1 having high resistance are applied to the outer circumferential surface of the cylindrical part 2, and a semi-conductive glaze P2 which becomes a conductive coating is also applied to the inner circumferential surface of the insertion hole 6 and fired. .

After the upper and lower caps 3, 4 are assembled to the porcelain main body 1, a portion extending from the upper surface of the upper cap 3 to the upper end of the inner circumferential surface of the insertion hole 6 across the upper surface of the porcelain main body 1, and the upper cap 3, a portion extending from the lower surface of the porcelain body 1 to the upper outer peripheral surface of the porcelain body 1, a portion extending from the lower surface of the flange 7 located at the lowest position in the porcelain body 1 to the upper surface of the lower cap 4, and a portion extending from the lower surface of the lower cap 4. Melting is performed using electricity or gas at five locations: a portion reaching the upper outer circumferential surface of the cylindrical portion 2, and a portion extending from the lower outer circumferential surface of the cylindrical portion 2 to the lower end of the inner circumferential surface of the insertion hole 6 across the lower surface. Conductive coatings P3, P4, P are formed by spraying metal such as lead with compressed air.
5, P6, and P7, so that the semiconductive glazes P0, P1 applied to the porcelain body 1 and the cylindrical portion 2 are electrically connected to the upper and lower caps 3, 4.

Furthermore, it is preferable to apply a thick layer of Vitomina paint over the area to which tamericon has been applied as described above.

On the other hand, a brass washer 8 is screwed onto the lower end of the conductive rod 5, and the washer 8 is brought into pressure contact with the lower surface of the cylindrical portion 2, so that the conductive rod 5 and the conductive glaze P1, P2 and are electrically connected via the washer 8.

Note that 9 in the figure indicates a gasket.

In this way, the above-mentioned insulator tube is in a state where electrical conduction is possible over the entire surface thereof, and moreover, the outer peripheral surfaces of the porcelain body 1 and the cylindrical portion 2 which are electrically connected to the lower cap 4 are connected to each other. Since the resistance of the applied semiconductive glazes P0 and P1 is very high, the potential difference between the conductive rod 5 and the inner circumferential surface of the insertion hole 6 or the outer circumferential surface of the porcelain body 1 and the cylindrical portion 2 is small. Therefore, even if the gap between the conductive rod 5 and the inner peripheral surface of the insertion hole 6 is narrowed, there is almost no risk of corona discharge occurring.

In the above embodiment, semiconductive glaze P0 was applied to the outer circumferential surface of the porcelain body 1 except for the fitting areas of the upper and lower caps 3 and 4, but a non-conductive ordinary glaze was applied to such areas. You may.

Furthermore, in the above embodiment, a semi-conductive glaze having a high resistance similar to the outer circumferential surface of the cylindrical portion 2 is applied to the inner circumferential surface of the insertion hole 6 to make the inner circumferential surface of the insertion hole 6 conductive. Although the coating film P2 is formed, the conductive coating film P2 may be formed on the inner peripheral surface of the insertion hole 6 by baking silver instead of the semiconductive glaze.

(Effects of the Invention) As described above, according to the present invention, the insertion hole 6 of the conductive rod 5 that connects the winding of the transformer and the overhead wire
a cylindrical porcelain body 1 having a cylindrical shape; an upper cap 3 fixed to the upper end of the porcelain body 1; and a transformer casing C fixed to the lower end of the porcelain body 1.
An insulator tube is provided with an electrically conductive lower cap 4 that is assembled into the porcelain body 1, and a cylindrical portion 2 that is inserted into the casing C is integrally formed at the lower end of the porcelain body 1,
A semiconductive glaze P with high resistance is applied to the outer peripheral surface of the cylindrical portion 2.
1 to electrically connect the upper end of the semiconductive glaze P1 to the lower cap 4, and also to electrically connect the lower end of the semiconductive glaze P1 to the conductive rod 5. On the other hand, the insertion hole 6
A conductive coating P2 is provided on the inner peripheral surface, and the conductive coating P2
The conductive rod 5 and Said cylindrical part 2
Since it is possible to reduce the potential difference between the inner peripheral surface of the insertion hole 6 formed in the porcelain body 1 and the outer peripheral surface of the cylindrical portion 2, the difference between the conductive rod 5 and the inner peripheral surface of the insertion hole 6 can be reduced. Even if the gap between the tubes is narrowed, there is almost no risk of corona discharge occurring, and the overall shape of the insulator tube can be made smaller while still suppressing the occurrence of corona discharge.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the insulator tube according to the present invention, and FIG. 2 is a schematic explanatory view showing the insulator tube assembled to a transformer. DESCRIPTION OF SYMBOLS 1... Porcelain body, 2... Cylindrical part, 3... Upper cap, 4... Lower cap, 5... Conductive rod, 6... Insertion hole, 8... Washer, P1... Semi-conductive glaze, P2 ...Conductive coating film, C...Casing.

Claims (1)

[Claims] 1 A cylindrical porcelain body 1 having an insertion hole 6 for a conductive rod 5 that connects the transformer winding and the overhead wire.
, an upper cap 3 fixed to the upper end of the porcelain main body 1, and an electrically conductive lower cap 4 fixed to the lower end of the porcelain main body 1 and assembled to the casing C of the transformer; A cylindrical part 2 which is inserted into the casing C is integrally formed at the lower end of the cylindrical part 2, and a semi-conductive glaze P1 having a large resistance is applied to the outer circumferential surface of the cylindrical part 2. A washer 8 is provided to electrically connect the upper end of the glaze P1 to the lower cap 4 and to electrically connect the lower end of the semiconductive glaze P1 to the conductive rod 5. A terminal of an overhead electric wire provided with a conductive coating P2 on its surface, the lower end of the conductive coating P2 being electrically connected to the washer 8, and the upper end of the conductive coating P2 being assembled to the upper cap 3. An insulator tube for a transformer, characterized in that it is electrically connected to a T.