JPS5835468A - Split-type transformer - Google Patents

Abstract

PURPOSE:To measure a current in a connecting lead without being affected by an electric field and a magnetic field, by providing an earthing cylindrical electrode between the outer-peripheral part of a connecting lead wire and the inner- peripheral surface of a connecting duct, and by fitting a sensor consisting of an optical fiber having a magnetooptical effect, etc. on the outer periphery of said electrode. CONSTITUTION:A high-voltage connecting lead wire 8 is led out from a winding 2 housed in a tank 3 and connectd to a high-voltage bushing through a duct 4. This lead wire 8 is covered with a lead insulator 17, while an earthing cylindrical electrode 19 is provided at the outer-peripheral part of the lead insulator 17 located inside the duct, through the intermediary of a supporting insulator 18. An optical fiber 20 having a magnetooptical effect is wound round the outer periphery of the electrode 19, and an optical fiber 21 is connected, as a lead for the input and output of a signal, to the optical fiber 20. By measuring a current in the optical fiber 20, a current in the winding of a transformer can be measured under no adverse effect of an electric field and a magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to a transformer, and more particularly to a measuring device using the JR magneto-optical effect for detecting the current in each winding.

As demand for electricity increases, transformers are becoming increasingly high-voltage and large-capacity. However, due to restrictions on railway transport, it is difficult to assemble such huge transformers with high power and large capacity, by replacing the three-phase transformer with three single-phase transformers and connecting them on-site, or by adding one-phase transformer. A method is adopted in which the image is divided into two or three parts.

FIG. 1 shows an example of a conventional two-part transformer, in which the contents of the transformer, in which a winding 2 is wound around an iron core 1, are housed in two slots 3, respectively. Both these tanks 3 are connected to a high pressure connecting duct 4
It is connected to the high-pressure bushing pocket 5 by a low-pressure bushing pocket 5 and to the low-pressure bushing pocket 7 by a low-pressure connecting duct 6 . High voltage connection lead wire 8 is inside the high voltage connection duct 4.
．． 9 passes through, and these join together to form a pressure weld = lead wire 10, which is connected to the high voltage pushphage 11. Low voltage connection lead wires 12 and 13 pass through the low voltage connection duct 6, and these join together to form the low voltage connection lead. A line 14 is connected to the low pressure bushing 15. Further, the two divided windings 2 are connected in parallel, and the current in the winding #J2 is measured as a winding-phase component, for example, by the bushing current transformer 16 on the high voltage side.

Generally, it is sufficient to measure the current at the connection between the transformer and the line (high-voltage bushing 11) as described above. However, in the case of the method of detecting an internal fault in a transformer by the difference between the high and low voltage side currents, when a small part of the winding is shorted, such as a -winding (1 turn) short circuit, the current that flows from the line to the transformer, that is, the connecting lead The power increasing portion of the accent flowing through the wires 10° and 14 years old is small, and is not necessarily sufficient to detect the current difference d and detect the target current difference r between the connecting lead wires 16 and 14 with the above-mentioned one configuration.

By the way, the connection lead d8.1 for each divided tank 3
Looking at the currents of 2, 9, and 13, the load current is halved in the -phase 2 minute h11, and 1/3 in the case of 3 divisions. However, the production sensitivity of the fault current superimposed on the current is doubled in the case of two divisions, and is improved by V'i3 in the case of three divisions. Therefore, the connection leads 8, 9, 12 from the divided tank 3
．． By measuring currents such as 13, it is possible to improve the detection sensitivity of transformer internal fault currents.

As shown in FIG. 1, a high voltage bushing current transformer 16 is typically used to measure the current flowing through the high voltage connection lead 10. However, for the above reasons, when trying to measure the current of each connection lead wire 8, 9, 12.13 with a bushing current transformer, the high , it becomes necessary to make the low-pressure connecting ducts 4 and 6 large enough to accommodate the bushing current transformer. However, it is desirable that these high and low voltage connecting ducts 4 and 6 be made as small as possible in order to reduce the size of the entire transformer for one phase.

Therefore, as a method for measuring current based on the above-mentioned constraints, there is a method using an optical fiber having a magneto-optic effect, a crystal having a magneto-optic effect, or the like. Since optical fiber has high electrical insulation properties, it is not impossible to install the sensor part near the high voltage part of the connecting lead wire, but considering the risk of creeping flash of the optical fiber, it is easy to connect the optical fiber to high voltage. cannot be pulled out from the measured position to the grounded tank. Therefore, various measures must be taken to prevent creeping flash of the optical fiber, such as providing an insulating structure or increasing the length from the high α pressure section to the ground tank. Alternatively, there is also a method of installing these sensors on the inner surface of a grounded tank to avoid high voltage from increasing in the sensor portion. However, all of the above-mentioned methods have the disadvantage that they are complicated in terms of manufacture and require special structures and operations for mounting the sensor.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a split type transformer that has a simple structure and can easily and highly sensitively measure the current flowing through each winding of a 11J transformer.

The present invention relates to an outer circumferential portion of a connecting lead wire of a transformer winding wired in a connecting duct that connects each tank housing a split transformer and an inner circumferential surface of the connecting duct in a parallel connection of split transformers. A grounded cylindrical electrode is provided between the grounded cylindrical electrode, and a sensor made of an optical fiber or crystal having a magneto-optical effect is attached to the outer periphery of the grounded cylindrical electrode. It is something to be measured.

Hereinafter, an embodiment of the split type transformer of the present invention will be described with reference to FIG. 2, in which the same parts as in the conventional example are denoted by the same reference numerals.

FIG. 2 shows a winding current measuring section which is a covering part of the split type transformer of this embodiment. A high voltage connection lead wire 8 is drawn out from the winding 2 housed in the tank 3, and this high voltage connection lead wire 8 passes through the high voltage connection duct 4, passes through the psuosing pocket, and connects to the high voltage bushing (see Figure 1). It is connected to the.

This high voltage connection lead wire 8 is covered with lead insulation 17. A grounded cylindrical electrode 19 is provided on the outer periphery of the lead insulator 17 in the high voltage connection duct 4 with a supporting insulator 18 interposed therebetween. A fiber 20 having a magneto-optical effect is wound around the outer periphery of this grounded cylindrical electrode 19, and an optical fiber 21 is connected to this fiber 20 as a lead-out for signal input/output.

The grounded cylindrical electrode 19 is made of a non-magnetic metal such as an impermeable steel plate or aluminum having a magnetic permeability of approximately 1, so that there is almost no difference in the magnetic field between the inside and outside of the grounded cylindrical electrode 19. . Therefore, by measuring the current value in the fiber 20 generated by the magnetic field caused by the current flowing through the connecting lead 8, it is possible to conversely estimate the current flowing through the connecting lead 8. The reason why we provided 19 grounded cylindrical type fibers is that without them, the fiber 20
must be attached to the inner surface of the connected duct 4, and then the influence of the electric field and magnetic field other than the connected eX')-dead wire 8 will be reduced
This is because there is a problem that an accurate current value cannot be detected due to the current value being 0.

According to this embodiment, the electric field is This has the effect of being able to measure the winding current of a split transformer without being adversely affected by the magnetic field and with a small and simple structure. In addition, since the current flowing through the connection lead wire of each divided winding can be detected using a method similar to that shown in Fig. Since it is possible to detect current return with high sensitivity, it has the effect of improving the reliability of the device and facilitating maintenance management.

FIG. 3 shows another embodiment of the invention. The difference between this embodiment and the embodiment shown in FIG. 2 is that a crystal 22 having a magneto-optical effect is attached to the outer surface of a grounded cylindrical electrode 19 as a sensor for current measurement. The rest of the structure is exactly the same as the embodiment shown in FIG. 2, and has the same effect.

FIG. 4 shows still another embodiment of the present invention.
The difference from the embodiment shown in FIG. 3 is that the grounded cylindrical electrode 19
A small hole 23 is made in one part of the 1-hole so that it is not affected by the magnetic field or the shadow of the magnetic field, and a crystal 22 having a magneto-optic effect is inserted and attached thereto. There is an effect.

According to the split type transformer of the present invention described above, the current flowing through each winding of the split transformer can be easily and highly sensitively measured with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the schematic configuration of a conventional two-split transformer;
Fig. 2 is an explanatory diagram showing the main parts of the split type transformer according to the present invention, and Fig. 3 is an explanatory diagram showing the main parts of the split type transformer according to the present invention. FIG. 4 is an explanatory diagram showing the essential parts of yet another embodiment of the split type transformer of the present invention. 2...Winding, 3...Tank, 4...High pressure connection duct, 5...High pressure bushing pocket, 6...Low pressure connection duct, 7...Low pressure bushing pocket, 8,9
．． 10...High voltage connection lead wire, 11...High pressure bushing, 12゜13.14...Low voltage connection lead wire, 15
...Low pressure bushing, 17...Lead insulation, 18.
... 1 gravel with no support, 19... grounded cylinder! Canopy, 2o...
・Phi, :, 22...Kii 9 hiri ni

Claims (1)

[Claims] 1. In a split transformer in which the lead wires connected to the windings of six transformers divided into a plurality of pieces pass through the connecting duct and are connected in parallel to the punching, A non-magnetic grounding pole is provided on the outer periphery of the lead wire, and a sensor having a magneto-optical effect is attached to the outer periphery of this grounding electrode.f
:, ff-characterized segmented plasmopressor. 2. The split-ill type transformer according to claim 1, characterized in that a small hole is provided in a part of the non-magnetic grounding electrode, and a sensor is mounted in the small hole.