JPH0360165B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a discharge position detection device for detecting a partial discharge position occurring in a stationary induction device such as a transformer. [Prior Art] In stationary induction equipment such as transformers, the position of partial discharge is detected by detecting ultrasonic waves caused by partial discharge generated inside the equipment from the tank wall. Conventionally, when detecting the position of a partial discharge in a stationary induction device, detection is performed using a discharge position detection device shown in FIG. Fourth
In the figure, first, a discharge pulse detector 3 is attached to the tank ground line 2 of the stationary induction device 1, and the discharge pulse detector 3 detects a reference voltage. Next, a plurality of ultrasonic detectors 4a to 4n directly attached to the wall of the tank 101 of the stationary guidance device 1 electrically detect ultrasonic waves caused by the partial discharge. Ultrasonic detector 4a
~4n outputs are amplified by amplifiers 5a~5n, and the output ultrasonic signals are sent to the discharge pulse detector 3.
is applied to the cathode ray tube oscilloscope 6 together with the detection voltage. On a cathode ray tube oscilloscope 6,
By sweeping the ultrasonic signals output from the amplifiers 5a to 5n with the corona pulse included in the detection voltage of the discharge pulse detector 3, the time at which the corona pulse signal was detected and each ultrasonic signal were detected. The time difference from the time is calculated, and the partial discharge position is detected from the time difference, the mounting positions of the ultrasonic detectors 4a to 4n, etc. FIG. 5 shows a corona pulse signal A included in the detection voltage of the discharge pulse detector 3 and an ultrasonic signal B which is the output of the amplifiers 5a to 5n, observed with the cathode ray tube oscilloscope 6. Time difference △t ₁ ~ △
tn is the time difference between the time when the corona pulse signal is detected and the signal detected by the ultrasonic detectors 4a to 4n. [Problems to be Solved by the Invention] The conventional discharge position detection device is configured as described above, and the ultrasonic detectors 4a to 4n are directly attached to the tank 101 of the stationary induction device 1, so that the problem caused by partial discharge It is difficult to distinguish between an ultrasonic signal and noise that is not related to partial discharge and is transmitted through the wall of the tank 101, for example, and the S/N is
There was a drawback that the detection accuracy of the partial discharge occurrence position deteriorated due to the poor ratio. In addition, if the detection sensitivity of the ultrasonic detectors 4a to 4n is increased in order to improve the S/N ratio, the noise level will also increase as well as the detection sensitivity, so the S/N ratio will not be improved much. It was hot. This invention was made in order to solve the above-mentioned problems, and an ultrasonic detector detects an ultrasonic signal from which noise has been removed, improving the detection accuracy of the position of partial discharge occurrence, and detecting even small partial discharges. The purpose is to obtain a discharge position detection device that can detect the discharge position. [Means for solving the problem] The discharge position detection device according to the present invention attenuates ultrasonic waves by connecting the opening of the tank to a mounting frame made of a material that easily attenuates ultrasonic waves propagated into the tank. It is covered with a mounting material made of a hard material, and an ultrasonic detector is attached to this mounting material. [Function] The discharge position detection device of the present invention includes a mounting frame made of a material that easily attenuates ultrasonic waves propagated into the tank around the opening of the tank, and a mounting frame made of a material that easily attenuates ultrasonic waves propagated into the tank. By covering the opening with the mounting material, the ultrasonic detector attached to the mounting material becomes less susceptible to the effects of ultrasonic noise propagated through the tank wall. [Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the discharge position detection device according to the present invention, and FIG. 2 is an enlarged view of the portion shown in FIG. 1. In FIGS. 1 and 2, the stationary induction device 1 is composed of a main body (not shown) and a tank 101 that houses the main body and is filled with, for example, insulating oil. Opening 1a
~1n is provided. The mounting frames 7a to 7n are made of a material that easily attenuates ultrasonic waves propagated to the tank, such as Bakelite, and are installed around the opening 1a. The mounting members 8a to 8n are made of a material that does not easily attenuate ultrasonic waves, such as glass, and are installed so as to cover the openings 1a to 1n like lids via the mounting frames 7a to 7n. Ultrasonic detector 4a~
4n are respectively attached to mounting members 8a to 8n,
For example, ultrasonic waves generated by partial discharge from the main body of the stationary guidance device 1 are received. The amplifiers 5a to 5n amplify the detected ultrasonic signals of the ultrasonic detectors 4a to 4n,
Ultrasonic signals 5a to 5n shown in FIG. 3 are obtained. The time difference measurement circuit 9 determines the detection order of the ultrasonic detectors 4a to _4n , and as shown in FIG.
Each detection time difference t _1-2 with ~nth detection signal A ₂ ~An,
Measure t _1-3 ,...t _1-o . The position detecting device 10 detects the partial discharge position of the stationary induction device 1 from the detected time difference of the time difference measuring circuit 9, and is composed of the following circuits and devices. The position detection calculation circuit 11 detects the partial discharge position of the stationary induction device 1 from the detection time difference of the time difference measurement circuit 9 and the mounting positions of the ultrasonic detectors 4a to 4n. The display device 12 displays the partial discharge position of the stationary induction device 1 detected by the position detection calculation circuit 11. The determination circuit 13 determines whether the partial discharge position detected by the position detection calculation circuit 11 is within the stationary induction device 1 or not, and causes the display device 12 to display the determination result. The amplitude determination circuit 14 is an ultrasonic detector 4a.
The maximum amplitude of each of the detection signals ~4n is compared with a set level, and when the maximum amplitude of the detection signal is equal to or higher than the set level, the partial discharge position detected by the position detection calculation circuit 11 is displayed on the display device 12. A detector 141 that obtains the maximum amplitude of the detection signal of each of the ultrasonic detectors 4a to 4n, a setter 142 that sets the setting level, and a setter 142 that sets the maximum amplitude obtained by the detector 141. The comparator 143 causes the display device 12 to display the partial discharge position detected by the position detection calculation circuit 11 when the partial discharge position is equal to or higher than the set level. Next, the operation will be explained. For example, ultrasonic waves caused by partial discharge of the main body of the stationary induction device 1 propagate only through the insulating oil, and from the insulating oil to the tank 101.
The ultrasonic detector 4a~ through the path propagating to the wall of
4n detected. In this case, the mounting frame 7a~ made of a material that easily attenuates the ultrasonic waves propagated to the tank.
7n, the ultrasonic waves on the path that propagates from the insulating oil to the wall of the tank 101 are significantly attenuated. Material 8a-8n
are detected by the ultrasonic detectors 4a to 4n.
The ultrasonic waves detected by the ultrasonic detectors 4a to 4n are
The ultrasonic waves are amplified by amplifiers 5a to 5n to obtain ultrasonic signals 5a to 5n shown in FIG. This ultrasonic signal 5a~
5n, the detection order is detected by the time difference measuring circuit 9,
The first detection signal detected first as shown in Figure 3
Detection time differences t _1-2 , t _1-3 , ..., between A ₁ and the second to nth detection signals A ₂ to An detected after the second position
Measure t _1-o . Based on these detection time differences and the mounting positions of the ultrasonic detectors 4a to 4n, etc., the position detection calculation circuit 11 detects the partial discharge position of the stationary induction device 1, and displays it on the display device 12. Further, the determination circuit 13 determines whether the partial discharge position detected by the position detection calculation circuit 11 is within the stationary induction device 1, and displays the determination result on the display device 1.
Display on 2. Furthermore, ultrasonic detectors 4a to 4
The maximum amplitude of each detection signal of n is detected by the detector 14.
The comparator 143 compares the amplitude obtained in step 1 with the set level set in the setter 142, and only when the maximum amplitude is equal to or higher than the set level, the position detection calculation circuit 11
Display device 1 displays the partial discharge position detected in
Display on 2. In other words, by changing the setting level of the installation device 142, it is possible to display on the display device 12 only when the pulse discharge voltage is equal to or higher than a desired pulse discharge voltage. Note that the discharge position can be detected only by the ultrasonic detectors 4a to 4n, and the conventional corona pulse detector 3 is not required. Next, the propagation velocity, acoustic impedance, and ultrasonic energy reflectance of various materials are shown in the following table.

〔Effect of the invention〕

As described above, according to the present invention, the opening of the tank is covered with a mounting material made of a material that does not easily attenuate ultrasonic waves propagated into the tank via a mounting frame made of a material that easily attenuates ultrasonic waves propagated into the tank. Since the ultrasonic detector is attached to the mounting material, the accuracy of detecting the discharge position is improved and even small partial discharges can be detected.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the discharge position detection device according to the present invention, FIG. 2 is an enlarged view of the portion shown in FIG. 1, and FIG. 3 is an output waveform diagram of the amplifier shown in FIG. FIG. 4 is a block diagram showing a conventional discharge position detection device, and FIG. 5 is an output waveform diagram of the discharge pulse detector of FIG. 4 and an output waveform diagram of the amplifier. In the figure, 1 is a stationary guidance device, 101 is a tank, 1a is an opening, 4a to 4n are ultrasonic detectors,
7a is a mounting frame, 8a to 8n are mounting materials, 9 is a time difference measuring circuit, 10 is a position detection device, 11 is a position detection calculation circuit, 12 is a display device, 13 is a determination circuit, 1
4 is an amplitude determination circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A tank that houses the main body of a stationary guidance device and has a plurality of openings, a mounting member that covers each of the openings via a mounting frame, and a plurality of ultrasonic waves attached to each of the mounting members. a detector, a time difference measurement circuit that measures the detection time difference between the first detection signal and the second and subsequent detection signals of the ultrasonic detector, and a partial discharge position of the stationary induction device based on the detection time difference of the time difference measurement circuit. A discharge position characterized in that the mounting frame is made of a material that easily attenuates ultrasonic waves propagated to the tank, and the mounting material is made of a material that does not easily attenuate ultrasonic waves. Detection device. 2. The position detection device includes a position detection calculation circuit that detects the partial discharge position of the stationary induction device from the detection time difference of the time difference measurement circuit and the installation position of the ultrasonic detector;
The discharge position detection device according to claim 1, further comprising a display device that displays the partial discharge position detected by the position detection calculation circuit. 3. The discharge position detection device according to claim 2, wherein the position detection device includes a determination circuit that determines whether or not the partial discharge position detected by the position detection calculation circuit is within a stationary induction device. 4. The position detection device compares the maximum amplitude of each detection signal of the ultrasonic detector with a set level, and when the maximum amplitude of the detection signal is equal to or higher than the set level, the position detection device detects the portion detected by the position detection calculation circuit. A discharge position detection device according to claim 2 or 3, comprising an amplitude determination circuit for displaying the discharge position on a display device.