JPS5919407Y2 - Multi-stage insulator current transformer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a current transformer whose lead portion is insulated by a capacitor cone and which is housed in a multi-stage laminate pipe.

FIG. 1 shows a conventional current transformer of this kind. As an example, a primary conductor 3 is placed in a multilayer capacitor 4 in two stacked insulator tubes 1 and 2.
It is insulated and installed.

An upper oil tank 5 is provided at the top of the insulator tube 1 to accommodate a primary terminal (not shown), and a lower oil tank 6 is provided at the bottom of the insulator tube 2 to accommodate current transformation consisting of the primary coil, secondary coil, and iron core. It houses the container body 7.

In this case, the insulator tubes 1 and 2 are provided with flanges 1a, 1b, 2a, and 2b as joint fittings at each end, and the insulator tubes are connected to each other and to the upper and lower oil tanks by tightening bolts 8.

A gasket 9 is inserted into each joint to provide an oil-tight structure.

Moreover, the multilayer capacitor 4 includes the primary conductor 3 and the electrode 10a,
10b, IOC, 10d, and insulating layer 11a,
In this case, it consists of four cylindrical capacitors of the same capacity connected in series between the primary conductor 3 and the outermost electrode 10d, that is, the ground, by 11b, 11C, and 11d.

Note that a shield ring 12a is provided at the end of each electrode.
, 12b, 12C, and 12d are installations.

The voltage of the primary conductor 3 is applied to these four capacitors.

A voltage of A is applied.

Here, if an external flash fault occurs at the flange portion of the joint as shown by arrow 15, it is necessary to prevent internal dielectric breakdown from occurring.

In contrast, conventionally, a potential plate 13 was provided between the joint flanges lb and 2a, and this was connected to the shield ring 12b of the multilayer capacitor by a lead wire 16, thereby fixing the potential of the joint flange portion.

However, in such a structure, since the equipotential plate 13 is provided, a packing 9 is provided between the upper and lower flanges lb and 2a.
It is necessary to use an oil-tight structure using a lead wire 16 and to connect the equipotential plate 13 and the shield ring 12b with a lead wire 16, which requires a lot of labor in the manufacturing and assembly process.

The present invention overcomes these drawbacks and will be explained below.

FIG. 2 shows an embodiment of the present invention, in which the same potential plates and lead wires in FIG. 1 are omitted, and in addition to a shield ring 12b, a A shield ring 12b' is provided, and the shield ring 12b is located at a position corresponding to the upper end of the upper flange 1b, and the shield ring 12b' is located at a position corresponding to the lower end of the lower flange 2a.

That is, there are shield rings 12b and 12b' opposite to the upper and lower ends of the flange portion of the seam, and 12b
and 12b' are set at the same potential as the electrode 10b.

Incidentally, at least koji (malt) is applied to the portion between the shield rings 12b and 12b' and the electrode 10b.

A solid insulating layer 14 corresponding to the voltage (voltage applied to the joint fitting portion of the insulator pipe under normal conditions) is provided.

In this way, the electrodes located at the outermost periphery of the joint fittings of the insulator are provided with shield rings at the upper and lower ends of the joint fittings, and both of these shield rings and the space between them are normally closed. It is covered with a solid insulating layer 14 corresponding to the voltage applied to the joint fitting portion.

Therefore, external flashover occurs on the surface of the insulator tube, causing a voltage ■ at the joint of the insulator tube.

Even if A.V.

The solid insulating layer 14 can sufficiently withstand this, and there is no risk of dielectric breakdown occurring.

By providing the shield ring 12b further above the upper end of the upper flange 1b and providing the shield ring 12b' further below the lower end of the lower flange 2a, the electric field relaxation effect on the joint flange can be made more effective.

In this way, when the present invention is used, when the lead part of the current transformer is housed in a multi-layered insulated pipe and insulated by a multi-layer capacitor, the electric sign plate is inserted between the joint flanges as in the conventional case. It does not require difficult work such as connecting the same potential plate to a shield ring of the same potential, and it reduces the backing structure that is disadvantageous in terms of sealing structure, such as making the upper and lower surfaces of the same potential board oil-tight, and simply connects the multilayer capacitor to a shield ring of the same potential. Only the number of shield rings 12b' is increased and the solid insulating layer 14 is provided.

These can be easily carried out, the labor required for assembly is greatly reduced and the structure is simpler than in the past.

As explained above, the present invention facilitates assembly and improves insulation performance, and has great advantages as a multistage porcelain current transformer.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a conventional capacitor-type current transformer in which insulator tubes are stacked in two stages, and FIG. 2 is a cross-sectional view showing an embodiment of the present invention. 1.2...Insulator pipe, 3...Primary conductor, 4
...Multilayer capacitor, 10a, 10b,
10 C, 10d --- Electrode, 11 a, 11
b, 11C, 11d --- insulation layer, 12a,
12b, 12b', 12C, 12d... Shield ring, 13... Equal potential plate, 14...
...Solid insulating layer.

Claims (1)

[Scope of utility model registration request] A lead portion insulated by a multilayer capacitor formed of a plurality of electrodes and an insulating layer is provided in the multi-layered insulator tube, and the outermost periphery of the plurality of electrodes is provided at the joint fitting portion of the multi-layered insulator tube. Shield rings are provided on the electrodes located at the upper and lower ends of the joint metal part, and solid insulation is connected between both shield rings and between them in a manner corresponding to the voltage applied to the joint metal part during normal operation. A multi-layered insulator type current transformer characterized by being covered with layers.