JP3100527B2 - Partial discharge detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detecting device for reliably detecting only a partial discharge generated in an electric device such as a transformer.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the configuration of a conventional partial discharge detecting device provided in a transformer as, for example, electric equipment. In the figure, 1 is a transformer, 2 is a bushing provided on the transformer 1, and 3 is a capacitor-type instrument transformer provided on the bushing 2 for detecting an electric signal generated by partial discharge in the transformer 1. (Hereinafter abbreviated as PD) 4 is a ground wire of the transformer 1, 5 is a high-frequency current detecting current transformer (hereinafter abbreviated as high-frequency CT) provided on the ground wire 4, and 6 is attached to the transformer 1. Ultrasonic sensor, 7
Is a signal processor which receives output signals of the PD 3, the high-frequency CT 5 and the ultrasonic sensor 6 and detects partial discharge.

[0003] Next, the operation of the conventional partial discharge detecting device configured as described above will be described. First, the transformer 1
When a partial discharge occurs in the inside, the PD 3 and the high frequency CT 5 detect an electric signal due to the partial discharge. Further, the ultrasonic sensor 6 detects the ultrasonic vibration of the transformer 1 caused by the partial discharge. Then, in the signal processor 7, PD3, high-frequency CT5
And the output signal detected from the ultrasonic sensor 6 is used to determine the time from the detection of the electric signal to the detection of the ultrasonic vibration, and the time from the mounting position of the ultrasonic sensor 6 to the occurrence position of the partial discharge is determined. Utilizing the fact that it is proportional to this time, the position where the partial discharge occurs is calculated from the ultrasonic sensor 6 from this time.

However, in the conventional partial discharge detecting device configured as described above, various noises enter and it is difficult to detect and determine only the partial discharge signal. Therefore, other conventional examples described below have been proposed.

FIG. 4 is a block diagram showing a configuration of another conventional partial discharge detecting device disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 62-140374. In the figure, reference numerals 8 and 9 denote two transformers placed in a similar noise environment, and 10 and 11 denote respective inductances La and Lb and resistance R from the transformers 8 and 9.
a, ground lines connected via Rb, 12, 1
3 is each transformer 8, 9 for drawing out each ground wire 10, 11.
, A differential amplifier for inputting an output signal from each of the ground terminals 12 and 13 through input terminals a and b, and 15 and 16 respectively attached to the transformers 8 and 9. The ultrasonic sensors 17 are signal processors which receive output signals from the ultrasonic sensors 15, 16 and the differential amplifier 14 and detect partial discharge.

Next, the operation of another conventional partial discharge detecting device configured as described above will be described. First, during normal operation of the transformers 8 and 9, there is almost no potential difference between the ground terminals 12 and 13 of the two transformers 8 and 9, so the differential amplifier 14 sends the signal to the signal processor 17. Do not output. Therefore, it is possible to prevent the signal processor 17 from erroneously starting due to noise.

Next, for example, if a partial discharge occurs on the transformer 8 side, a partial discharge pulse current flows through the ground line 12 of the transformer 8, so that this pulse current and the ground line 10
And the potential of the ground terminal 12 of the transformer 8 rises by a level determined by the impedance of the transformer 8. Therefore, each ground terminal 1
A potential difference occurs between 2 and 13, and the differential amplifier 14 outputs a signal to the signal processor 17. Then, in the same manner as in the conventional case, the signal processor 17 calculates the position where the partial discharge occurs based on the signals from the ultrasonic sensors 15 and 16 and the signal from the differential amplifier 14.

[0008]

The conventional partial discharge detecting device is constructed as described above, and outputs the potential difference between the ground terminals 12 and 13 of the transformers 8 and 9 by the differential amplifier 14. Although the effects of noise are prevented, the structures and characteristics of the transformers 8 and 9 are various, so that the ground terminals 12 and 13 are provided for all various noises.
Does not always detect the same value, it is impossible to deal with all kinds of noise, and there is a problem that it cannot be denied that it is affected by noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a partial discharge detection device capable of detecting a partial discharge of an electric device without being affected by various noises. With the goal.

[0010]

Means for Solving the Problems Claim 1 according to the present invention.
Is composed of a pair of device parts having the same rating and the same structure, which are obtained by dividing an electrical device into two mirror-symmetrically, and providing a pair of ground wires at mirror-symmetric positions of the pair of device portions, respectively. The partial discharge is detected from the differential signal of the signal of the ground line of FIG.

According to a second aspect of the present invention, there is provided a partial discharge detecting apparatus according to the first aspect, wherein a plurality of pairs of ground lines are provided, and differential signals of signals of each pair of ground lines are added for a plurality of pairs. To detect partial discharge.

[0012]

In the partial discharge detecting device according to the first aspect of the present invention, since a signal due to noise is generated with a value equal to a pair of ground lines and these signals are surely canceled out by taking a differential, the noise is eliminated. Obtains only a signal due to discharge.

Further, the partial discharge detecting device according to the second aspect of the present invention can obtain a signal by partial discharge from which noise has been removed with high sensitivity.

[0014]

【Example】

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a partial discharge detection device according to Embodiment 1 of the present invention. FIG. 2 is a sectional view taken along line II-II of the partial discharge detection device shown in FIG. In the figure, reference numeral 18 denotes a transformer as an electric device,
Numeral 0 denotes a pair of equipment units 21 and 22 having the same rating and the same structure in which the transformer 18 is divided into two mirror-symmetrically with respect to the line A as a central axis.
Are a pair of ground wires provided at mirror symmetrical positions of the pair of device portions 19 and 20, respectively, and 23 and 24 are another pair of ground wires similarly provided at positions different from the pair of ground wires 21 and 22. The ground lines 25, 26, 27, and 28 are high-frequency CTs respectively provided for extracting signals of the plural pairs of ground lines 21, 22, 23, and 24.

Reference numeral 29 denotes a first differential amplifier which receives signals from the pair of high-frequency CTs 25 and 26 from the + and-terminals, respectively, to take a differential, and 30 denotes another pair of high-frequency CTs 27 and 2.
The second differential amplifier takes the signal of signal No. 8 from the negative terminal and the positive terminal, respectively, and takes a differential signal. 19, 20
Are input in reverse. 31 is the first
And an amplifier for inputting and adding the differential signals of the second differential amplifiers 29 and 30 from the positive and negative terminals, and a signal processor 32 for detecting a partial discharge based on the signal from the amplifier 31.

Next, the operation of the partial discharge detection device of the first embodiment configured as described above will be described. First, at the time of normal operation of both the equipment sections 19 and 20, ie, the transformer 18,
Even though each pair of high-frequency CTs 25, 26 and 27, 28 respectively detect noise, the signal is
Since T25, 26 and 27, 28 always have the same value, the differential signal of the first and second differential amplifiers 29, 30 becomes zero. Therefore, noise is not erroneously detected as partial discharge. This is because both the equipment parts 19 and 20 are formed in the same rating and the same structure in which the two equipment parts 19 and 20 are mirror-symmetrically divided into two, and the ground wires 21, 22 and 23 and 24 of each pair are provided at mirror-symmetric positions. This is because various noises are always detected by the pair of high-frequency CTs 25, 26 and 27, 28 with the same value.

Next, for example, assuming that a partial discharge has occurred on the device section 19 side of the transformer 18, one of the pair of high-frequency CT2
5 and 27 detect a value greater than the other high-frequency CTs 26 and 28 of the pair, and the first and second differential amplifiers 29 and 30 output differential signals, respectively. At this time, it goes without saying that noise has been removed from the same idea as described above. Then, the amplifier 31 adds and amplifies the differential signals input from the two differential amplifiers 29 and 30 in the opposite direction ± to the + side, amplifies the differential signals, and outputs the amplified signals to the signal processor 32. The signal processor 32 processes this signal to detect a partial discharge.

The partial discharge detection device of the first embodiment constructed as described above is composed of a pair of equipment sections 19 and 20 having the same rating and the same structure obtained by dividing the transformer 18 into two mirror-symmetric parts. Each pair of ground lines 25, 26 and 27, 28 is provided at each mirror symmetric position of the parts 19, 20 to detect signals, obtain differential signals, and detect partial discharges. While reliably removing,
Since a plurality of differential signals are taken and added, the partial discharge can be detected with high sensitivity.

In the first embodiment, the ultrasonic sensor for detecting the ultrasonic vibration and the like are omitted as in each of the above-mentioned prior arts. Needless to say, the signal of each of the ground lines 21, 22, 23, and 24 may be, for example, a signal other than the high-frequency CT, such as a voltage.

In the first embodiment, the description is made with reference to a single-phase diagram of the transformer 18. However, the same can be said for example with three-phase one bank or several banks. Although the transformer 18 has been described as an example of the electric equipment, other electric equipment such as a reactor can be similarly used.

Embodiment 2 FIG. In the first embodiment, the pair of ground wires 2
Although an example has been described in which a plurality of pairs of 1, 22, 23, and 24 are provided, for example, if only one pair of ground lines is provided, a differential signal from which noise has been removed can be reliably obtained. Of course, partial discharge can be detected. Needless to say, if more than two pairs of ground lines are provided and the differential signals are added to detect a partial discharge, the sensitivity is further improved.

[0022]

As described above, according to the first aspect of the present invention, an electric device is constituted by a pair of device parts having the same rating and the same structure, which are divided into two mirror-symmetrically, and the ground wire is connected to the pair of device parts. Are provided in a mirror symmetrical position, and a partial discharge is detected from a differential signal of the signal of the pair of ground lines, so that various noises can be reliably removed and only the partial discharge can be detected. It is possible to provide a partial discharge detection device.

According to a second aspect of the present invention, in the first aspect, a plurality of pairs of ground lines are provided, and a partial discharge is performed by adding a plurality of pairs of differential signals of the signals of each pair of ground lines. Since the detection is performed, it is possible to provide a partial discharge detection device capable of reliably removing various noises and detecting only partial discharge with high sensitivity.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a partial discharge detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing details of a mounting position of each ground wire in the partial discharge detection device shown in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional partial discharge detection device.

FIG. 4 is a block diagram showing a configuration of another conventional partial discharge detection device.

[Explanation of symbols]

18 Transformers, 19, 20 Equipment, 21, 22, 2
3,24 Ground wire, 25,26,27,28 High frequency C
T, 29 First differential amplifier, 30 Second differential amplifier, 31 Amplifier, 32 Signal processor.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31 / 12,31 / 32

Claims (2)

(57) [Claims] 1. A partial discharge detection device for detecting a partial discharge from a differential signal of a pair of ground lines provided in an electric device, wherein the electric device is divided into two mirror-symmetrically and has the same rating and the same structure. A partial discharge detection device comprising: a plurality of device parts; and a pair of ground lines provided at mirror-symmetric positions of the pair of device parts. 2. A part according to claim 1, wherein a plurality of pairs of ground lines are provided, and a partial discharge is detected by adding the differential signals of the signals of the pair of ground lines by the plurality of pairs. Discharge detection device.