JPH05322963A - Partial discharge measuring device for resin mold transformer - Google Patents

Abstract

PURPOSE:To measure partial discharge without removing a connection conductor which connects a tap terminal. CONSTITUTION:A partial discharge sensor is built into a connection conductor 17 which connects a tap terminal 4 of a high voltage coil winding 3 and at the same time an amplification part is built into the input side within an E/O conversion part 18. The output terminal of a partial discharge sensor and the input terminal of the amplification part are formed at an insertion-type connector 19 where they can be engaged each other. Also, the E/O conversion part 18 is constituted so that it is supported at the high voltage coil winding 3 side of a resin mold transformer only by the engagement of the connector 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring a partial discharge generated inside a winding of a resin-molded transformer.

[0002]

2. Description of the Related Art FIG. 5 is a front view showing a structural example of a three-phase resin molded transformer. In the resin-molded transformer, a three-phase high-voltage winding 3 is wound around each main leg of a tripod iron core 2 held by a frame 1. The high-voltage winding 3 is formed by molding the entire winding conductor with epoxy resin, and its outer shape is a substantially cylindrical shape. A low voltage winding (not shown) is arranged on the inner diameter side of the high voltage winding 3, and the low voltage winding is also wound around the main leg of the iron core 2. A plurality of tap terminals 4 are provided outside each high-voltage winding 3, and are short-circuited via a connection conductor 5. The interphase lead connecting portion 6 is an epoxy resin casting body in which leads (not shown) for connecting the phases of the high voltage winding 3 are embedded. The interphase lead connecting portion 6 is also provided with a high voltage terminal 7 for outputting a three-phase voltage to the outside.

Generally, the resin mold transformer is not housed in a dedicated tank, but is placed as it is in a room or a switchboard. The tap change of the resin mold transformer is performed by the high voltage winding 3
Is set to a non-voltage state, and then the connection conductor 5 is reconnected to a predetermined tap terminal 4. FIG. 6 is a block diagram showing a method for measuring partial discharge of a resin mold transformer. This method is a method of detecting partial discharge from the connection conductor 5 that short-circuits the tap terminal 4 of the high-voltage winding 3. The partial discharge is measured by measuring the partial discharge sensor 9 and the amplification unit 10,
E / O converter 11, optical fiber 12, O / E converter 1
3. The partial discharge measuring device 8 including the indicator 14 is used.

In FIG. 6, the partial discharge sensor 9 is formed of a through type current transformer, penetrates the connecting conductor 5, and its secondary side output is sent to the amplifying section 10. The amplifier 10 amplifies the input signal and outputs it to the E / O converter 11. E / O converter 1
1 converts an input signal into an optical signal and outputs it to the optical fiber 12. The optical fiber 12 transmits an optical signal to the O / E converter 13. The O / E converter 13 converts the input optical signal into an electric signal and outputs the electric signal to the instruction unit 14. Based on the input signal, the instruction unit 14 displays the magnitude and frequency of partial discharge on a meter, an oscilloscope, or the like. in this way,
The method for detecting partial discharge from the connecting conductor 5 of the tap terminal 4 has already been applied for by the same applicant as the present invention.
(JP-A-3-216564). By detecting the partial discharge current flowing through the connecting conductor 5, the partial discharge generated inside the high voltage winding 3 can be measured with high sensitivity. The partial discharge sensor 9 is sequentially reconnected to the high-voltage winding 3 of each phase, and the partial discharge measurement is performed three times in total.

FIG. 7 is a side view of essential parts showing a configuration example of a conventional partial discharge measuring apparatus for a resin mold transformer. A rod-shaped connecting conductor 5 is bridged and bolted between tap terminals 4 provided on the high voltage winding 3 of the resin molded transformer.
The partial discharge sensor 9 is passed through the connection conductor 5, and the output signal is received by the amplifier 10. The amplification unit 10 and the E / O conversion unit 11 are mounted on an insulating base 15 arranged on the ground 16. The output signal of the E / O converter 11 is transmitted through the optical fiber 12 to the O / E converter 1 on the ground 16.
3 receives. Further, the indicator 14 receives the output signal of the O / E converter 13.

In FIG. 7, the reason why the insulating base 15 is necessary is that the amplifying section 10 and the E / O converting section 11 are provided with the tap terminal 4.
This is because it is at the same high potential as. Further, the amplification unit 10 and the E / O conversion unit 11 also incorporate a battery required for operation.

[0007]

However, the conventional device as described above has a problem that the connecting conductor must be removed each time the partial discharge is measured. In order to penetrate the connection conductor through the partial discharge sensor, it was necessary to temporarily remove it from the connection conductor and the tap terminal. Moreover, in the case of a three-phase transformer, it is necessary to attach and detach the connecting conductor three times in order to attach the partial discharge sensor to each high voltage winding. Therefore, the preparation work required for the partial discharge measurement took time. In addition, the connection conductor is where the energizing current of the resin molded transformer flows, and if the bolts are improperly tightened, a serious accident may occur. In the past, after measuring partial discharge, the mounting state of the connecting conductor including the torque control of the bolt was carefully checked before restarting the operation of the resin mold transformer. It has been said that it is preferable not to remove the connecting conductor as much as possible.

An object of the present invention is to enable partial discharge measurement without removing the connecting conductor.

[0009]

To achieve the above object, according to the present invention, there is a non-voltage switching type tap terminal on the high voltage winding side, and the tap terminals are short-circuited by a connecting conductor. An apparatus for measuring partial discharge of a resin mold transformer, comprising a partial discharge sensor consisting of a penetrating current transformer penetrating the connection conductor, an amplification section for amplifying an output signal of the partial discharge sensor, and An E / O converter for converting the output signal of the amplifier into an optical signal, an optical fiber for transmitting the output signal of the E / O converter, and an O for converting the optical signal transmitted by the optical fiber into an electric signal. / E converter and this O /
An E-conversion unit for displaying the magnitude of the output signal, the connection conductor and the partial discharge sensor are integrally formed, and the amplification unit and the E / O conversion unit are integrally formed, It is assumed that the output end of the partial discharge sensor and the input end of the amplification section form a plug-in connector that can be fitted to each other.
The integrated O / O converter is supported on the resin mold transformer side only by fitting the plug-in connector.

[0010]

According to the structure of the present invention, the connecting conductor and the partial discharge sensor are integrated, and the amplifying section and the E / O converting section are also integrated. Further, the output terminal of the partial discharge sensor and the input terminal of the amplification section are formed into a plug connector which can be fitted to each other. With this configuration, the partial discharge measurement only needs to be performed by inserting the connector, so that it is not necessary to remove the connection conductor.

In addition to the above configuration, an amplifier and an O / E
The integrated converter is configured to be supported on the resin-molded transformer side only by fitting the plug-in connector. This eliminates the need for an insulating base during partial discharge measurement, and can reduce the number of parts of the measurement jig. Further, in addition to the above configuration, the periphery of the partial discharge sensor is covered with the connection conductor. With this configuration, the partial discharge sensor cannot be seen from the outside of the resin mold transformer, so that the aesthetic appearance of the transformer in operation can be maintained.

[0012]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a side view of essential parts showing the configuration of a partial discharge measuring apparatus for a resin mold transformer according to an embodiment of the present invention. The connection conductor 17 having the partial discharge sensor housed therein is attached between the tap terminals 4, and the E / O converter 18 having the amplifier part housed on the inside input side via the connector 19 has the high-voltage winding 3
Supported by the side. Other configurations are the same as the conventional ones. Therefore, the same reference numerals are used for the same portions and detailed description thereof will be omitted.

FIG. 2 is an enlarged sectional view showing the structure of the connection conductor 17 of FIG. 1, and FIG. 3 is an XX sectional view of FIG. In FIG. 2, two cylindrical portions 17A and 17B in which the connection conductor 17 contacts the tap terminal 4 and the cylindrical portions 17A and 17B.
And a connecting portion 17C that electrically connects them. The connection conductor 17 is fixed to the tap terminal 4 via a bolt 20 penetrating the hollow portions of the cylindrical portions 17A and 17B. The connection conductor 17 houses the partial discharge sensor 21 inside via a supporting insulator (not shown). Partial discharge sensor 2
Reference numeral 1 includes a toroidal ferrite portion 21A surrounding the outer periphery of the cylindrical portion 17A, and a secondary winding 21B winding the ferrite portion 21A. The connection conductor 17 is further provided with a receptacle 22. The receptacle 22 has an inner conductor 22A having a fitting hole at the center.
And an outer conductor 22C arranged on the outer circumference of the inner conductor 22A via an insulation 22B. Outer conductor 22C
Is a ring-shaped insulating ring 22
It is fixed to the connecting conductor 17 by a nut 22D via E. The output side of the secondary winding 21B is connected to the receptacle 2
The two inner conductors 22A and the outer conductor 22C are conductively connected to each other and electrically insulated from the connection conductor 17.

In FIG. 3, the connecting portion 17 of the connecting conductor 17 is connected.
C has a shape in which one side is expanded because the partial discharge sensor 21 is incorporated. The current output from the tap terminal 4 of the high voltage winding 3 is supplied to the cylindrical portion 17A of the connecting conductor 17 and the connecting portion 17
C, flowing through the cylindrical portion 17B and flowing into another tap terminal 4. Since a current flows through the cylindrical portion 17A penetrating the center of the ferrite portion 21A, an electric signal is induced in the secondary winding 21B when a partial discharge occurs in the high voltage winding 3, and the electric signal is generated inside the receptacle 22. It is output to the conductor 22A and the outer conductor 22C.

FIG. 4 is an enlarged cross-sectional view of an essential part showing the structure of the E / O converter 18 of FIG. E / O converter 18 is case 2
An amplifier, an E / O converter, and a battery, which are not shown, are incorporated in the device 3. Plug 24 into the opening in case 23
Is equipped with. The plug 24 has a needle-shaped inner conductor 24 at the center.
A and an outer conductor 24C arranged on the outer periphery of the inner conductor 24A via an insulation 24B. Outer conductor 24
C has a threaded portion on the outer circumference, and is an insulating ring 2 having a U-shaped cross section
It is fixed to the case 23 by a nut 24D via 4E. The inner conductor 24A and the outer conductor 24C are connected to the amplification section inside the case 23 while being insulated from the case 23. The plug 24 of FIG. 4 and the receptacle 22 of FIG. 2 can be fitted to each other. When fitted together, the connector 19 is formed as shown in FIG.
8 is fixed to the high voltage winding 3 side.

With the connector 19 connected, the inner conductor 24A of the plug 24 in FIG. 4 is just fitted into the fitting hole of the inner conductor 22A of the receptacle 22 in FIG. 2, and the outer conductor 24C of the plug 24 is in the receptacle. The outer conductor 22C of 22 fits outside. Therefore, the E / O converter 1
8 can be easily attached to and removed from the connection conductor 17 by hand. Moreover, by removing the E / O converter 18, the resin-molded transformer can be operated with the connecting conductor 17 still attached to the high-voltage winding 3.

As shown in FIG. 1, in order to fix the E / O converter 18 to the high-voltage winding 3 side only with the connector 19, the E / O converter 18 is made as compact and lightweight as possible. Better. Therefore, the case 23 of the E / O converter 18 may be made of, for example, a lightweight ABS resin.
If the case 23 is insulative, the plug 24 in FIG.
Insulating ring 24E is unnecessary.

Further, the partial discharge sensor 21 does not necessarily have to be housed inside the connection conductor 17 as shown in FIG. What is essential is that the partial discharge sensor 21 penetrates the connection conductor 17 and is fixed integrally with the connection conductor 17, and includes the receptacle 22 that outputs a detection signal of the partial discharge. However, as shown in FIG. 2, by covering the partial discharge sensor 21 with the connecting portion 17C of the connecting conductor 17, the partial discharge sensor 21 cannot be seen from the outside and the appearance of the transformer in operation can be maintained.

[0019]

As described above, according to the present invention, the connecting conductor and the partial discharge sensor are integrated, and the amplifying section and the E / O are integrated.
The conversion unit is also integrally configured. Further, the output terminal of the partial discharge sensor and the input terminal of the amplification section are formed into a plug connector which can be fitted to each other. With this configuration, the partial discharge measurement only needs to be performed by inserting the connector, so that it is not necessary to remove the connection conductor. Therefore, the preparation time for the partial discharge measurement is reduced, and the connection failure of the connection conductor to the tap terminal and the tap terminal selection error are eliminated.

In addition to the above configuration, an amplifier and an O / E
The integrated converter is configured to be supported on the resin-molded transformer side only by fitting the plug-in connector. This eliminates the need for an insulating base during partial discharge measurement, and can reduce the number of parts of the measurement jig. Furthermore, in addition to the above configuration, the periphery of the partial discharge sensor is covered with a connection conductor. As a result, the partial discharge sensor is hidden from the outside of the resin-molded transformer, so that the aesthetic appearance of the transformer in operation is maintained.

[Brief description of drawings]

FIG. 1 is a side view of essential parts showing the configuration of a partial discharge measuring device for a resin mold transformer according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the configuration of the connection conductor of FIG.

3 is a sectional view taken along line XX of FIG.

FIG. 4 is an enlarged sectional view of an essential part showing the configuration of the E / O conversion part in FIG.

FIG. 5 is a front view showing a configuration example of a three-phase resin-molded transformer.

FIG. 6 is a block diagram showing a method of measuring partial discharge of a resin mold transformer.

FIG. 7 is a side view of essential parts showing a configuration example of a conventional partial discharge measuring device for a resin-molded transformer.

[Explanation of symbols]

 1 frame 2 iron core 3 high voltage winding 4 tap terminal 12 optical fiber 13 O / E converter 14 indicator 16 earth 17 connection conductor 17A cylindrical part 17B cylindrical part 17C connecting part 18 E / O converter 19 connector 20 bolt 21 partial discharge Sensor 21A Ferrite part 21B Secondary winding 22 Receptacle 23 Case 24 Plug 22A Inner conductor 24A Inner conductor 22B Insulation 24B Insulation 22C Outer conductor 24C Outer conductor 22D Nut 24D Nut 22E Insulation ring 24E Insulation ring

Claims (3)

[Claims] 1. A device for measuring a partial discharge of a resin-molded transformer, which has a non-voltage switching type tap terminal on the high-voltage winding side, and the tap terminals are short-circuited by a connecting conductor. A partial discharge sensor consisting of a through-type current transformer penetrating the connection conductor, an amplification section for amplifying the output signal of this partial discharge sensor, and an E / O conversion section for converting the output signal of this amplification section into an optical signal, An optical fiber for transmitting the output signal of the E / O converter, an O / E converter for converting the optical signal transmitted by the optical fiber into an electric signal, and the magnitude of the output signal of the O / E converter Is provided, the connection conductor and the partial discharge sensor are integrally formed, and the amplification unit and the E / O conversion unit are integrally formed, and the output end of the partial discharge sensor and the Insertion so that the input end of the amplification section can be fitted together Partial discharge measuring device of the resin mold transformer, characterized in that by forming a shape connector. 2. The amplifier according to claim 1, wherein the amplifier and E
A partial discharge measuring device for a resin mold transformer, wherein the integrated O / O converter is supported on the resin mold transformer side only by fitting a plug-in connector. 3. The device according to claim 1 or 2,
A partial discharge measuring device for a resin mold transformer, characterized in that the periphery of the partial discharge sensor is covered with a connecting conductor.