JPH0365666A - Abnormality detector for static guidance apparatus - Google Patents

Abstract

PURPOSE:To achieve a simplification of an entire construction and a higher reliability by checking an electromagnetic wave generated from a winding within an equipment (transformer) to detect abnormality of the winding by discriminating a frequency component thereof. CONSTITUTION:When a local short-circuiting/partial discharge is generated in primary and secondary windings 13 and 14 within a tank 11, an electromagnetic wave with a frequency 50Hz (power source voltage frequency)/1-100MHz corresponding thereto is released to be interlinked with an antenna 16 of a sensor 15. The antenna 16 outputs a measurement signal indicating a frequency of the electromagnetic wave and the measuring signal is amplified 17 to be inputted into BPFs 18 and 19. The BPFs 18 and 19 discriminate a signal with a frequency band width of 50Hz and 1-100MHz respectively while outputting a pulse signal indicating an intensity thereof through an optical fiber 20. An abnormality detecting means (signal processor) 21 detects a frequency and intensity of the electromagnetic wave interlinked with the antenna 16 based on a pulse light applied through the optical fiber 20 and can detect a local short- circuiting or a partial discharge in the windings 13 and 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an abnormality detection device for stationary induction equipment for detecting partial discharge or local short circuit occurring in a winding.

(Prior Art) Transformers, which are static induction devices, are susceptible to various abnormalities such as local short circuits or partial discharges in their internal windings.
It is desired to detect and deal with them early.

Now, a local short circuit occurs when windings are short-circuited, and the occurrence of partial discharge at that time increases the current flowing through the windings, which may cause burnout. Therefore, conventionally,
Various methods have been considered for detecting local short circuits in windings.

As an example of a detection method, it has been considered to detect the leakage flux based on a variation in the distribution of leakage magnetic flux due to the occurrence of a local short circuit in the winding. In other words, if a local short circuit occurs in the winding, the distribution of leakage magnetic flux from the winding will change from the normal distribution, so it is recommended to install a sensor in the range where this change occurs and use this to detect the change in the leakage flux distribution. That is to say. In this case, since the frequency of the leakage flux corresponds to the frequency of the power supply voltage applied to the primary winding, if the measurement signal from the sensor is an electromagnetic wave corresponding to the power supply frequency, it is determined that a local short circuit has occurred. be able to.

On the other hand, partial discharge is a phenomenon in which dielectric breakdown occurs partially in the winding or the insulation of the lead wire connected to the winding when electric field concentration occurs due to high voltage being applied to the winding. .

The intensity of this partial discharge is usually relatively low, but if it continues for a long time, the solid insulation of the windings will gradually erode.
Eventually, this may progress to dielectric breakdown. Therefore, when partial discharge occurs beyond the limit, the insulation function of the winding must be diagnosed as a precursor to total circuit breakdown. Therefore, conventional methods for detecting partial discharges that occur in windings include audible sounds, ultrasonic waves, and electromagnetic waves that are generated due to partial discharges.

Various devices have been provided that detect the occurrence of partial discharge by detecting optical partial discharge current and the like.

FIG. 12 shows an example of a device for detecting electromagnetic waves generated due to partial discharge. That is, a sensor 3 for detecting electromagnetic waves is provided in a tank 2 in which a transformer main body 1 is built.

This sensor 3 is connected to an antenna 4. An amplifier 5 that amplifies the measurement signal from this antenna 4. Of the signals amplified by this amplifier 5, from IMHz to 100MHz
It is composed of a bandpass filter 6, etc., which discriminates frequencies up to.

Now, when a partial discharge occurs in the transformer 1, an electromagnetic wave is emitted along with it, and this electromagnetic wave interlinks with the antenna 4. Since the main component of the frequency of the electromagnetic waves emitted with the partial discharge at this time is from I MHz to 100 MHz, the measurement signal from antenna 4 is from I MHz to 100 MHz.
When it passes through the band pass filter 6 that discriminates 2,
A voltage signal is output from the sensor 3. Therefore, the signal processing device 7 can determine the occurrence of partial discharge based on the voltage signal. Here, since the magnitude of the voltage signal output from the sensor 3 and the amount of discharged charge released by partial discharge have a correlation as shown in FIG. 13, the magnitude of the amount of discharged charge can be determined based on the magnitude of the voltage signal. can be found.

In addition, in the case of the above configuration, the tank 2 is sealed and electrical noise (electromagnetic waves) is difficult to penetrate, so the noise ratio of the sensor 3 is high, and the sensor 3 is insulated from the transformer 1. Therefore, even if the sensor 3 fails, the transformer 1 is not affected in any way.

(Problem to be Solved by the Invention) By the way, the above-mentioned sensors for detecting local short circuits and partial discharges have individual configurations even though they both have a common function of detecting electromagnetic waves. there were.

Therefore, when trying to detect both local short circuits and partial discharges, each sensor must be installed individually, which not only complicates the overall configuration, but also increases the reliability of the entire device due to multiple detection elements. There is a risk that the performance may deteriorate. This reduction in reliability of the device means that it cannot respond to abnormalities that occur in the transformer, which is thought to have a longer lifespan than the sensor.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an abnormality detection device for stationary guidance equipment that can simplify the overall configuration and improve reliability.

[Structure of the Invention] (Means for Solving the Problem) The abnormality detection device for a stationary induction device of the present invention detects an electromagnetic wave generated from a winding in a stationary induction device and outputs a measurement signal indicating the frequency of the electromagnetic wave. A measuring device is provided, and a discriminator is provided to discriminate each frequency component that occurs due to partial discharge and local short circuit among the measurement signals from this measuring device. An abnormality detection means is provided to detect the occurrence of an abnormality.

(Function) When a local short circuit occurs in the winding, an electromagnetic wave having a frequency corresponding to the local short circuit is emitted from the winding. On the other hand, when partial discharge occurs in the winding, electromagnetic waves with a frequency corresponding to the partial discharge are emitted from the winding, and the electromagnetic waves intersect with the measuring device. The measuring device then outputs a measurement signal indicating the frequency of the electromagnetic wave.

At this time, the discriminator discriminates the frequency component of electromagnetic waves associated with partial discharge or local short circuit among the measurement signals from the measuring device. Therefore, the abnormality detection means detects the occurrence of partial discharge or local short circuit based on the discrimination result of the discriminator.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 to 7.

In FIG. 1, an iron core 12 is disposed within a tank 11, and a primary winding 13 and a secondary winding 14 are wound around the iron core 12. An appropriate insulation distance is maintained between the iron core 12 and the primary winding 13, the primary winding 13, and the secondary winding 13.14, and insulating oil, SF, air, etc. are used as the insulation material. Here, when insulating oil and SFb are used as the insulating material, they are sealed in a tank, and when air is used, they are stored and used in a case communicated with the outside.

On the other hand, a sensor 15 is provided in the tank 11. This sensor 15 has a winding 1 on a ferrite core 16a, for example.
Antenna 16, which is a measuring device, is made by winding a plurality of turns of 6b.
．． Amplifier 1 that amplifies the measured voltage from this antenna 16
7. It is comprised of a first band-pass filter 18 and a second band-pass filter 19, each serving as a discriminator that discriminates and passes only signals of a predetermined frequency among the signals from the amplifier 17. In this case, the first bandpass filter 18 discriminates signals in a frequency band of, for example, 50 Hz, which is the frequency of the power supply voltage applied to the primary winding 13, and outputs a pulse signal indicating the intensity thereof through the optical fiber. Further, the second bandpass filter 19 discriminates signals from IMHz to 100MHz and outputs pulsed light indicating the intensity thereof through the optical fiber 20. A signal processing device 21 serving as an abnormality detection means receives a first signal provided through an optical fiber 20. Second bandpass filter 18.
The frequency and intensity of electromagnetic waves linked to the antenna 16 are detected based on the pulsed light from the antenna 19 .

Next, the above configuration will be explained.

If a local short circuit occurs in the primary winding 13 or the secondary winding 14 during operation of the transformer, the local short circuit can be detected as follows. When the load is removed from the secondary winding 14, a strong leakage magnetic flux with a distribution as shown in FIG. 2(a) is generated in each winding 113, 14. Here, for example, if a local short circuit occurs in the secondary winding 13, a local magnetic flux imbalance occurs and a part of the distribution of leakage magnetic flux from each winding 13, 14 is disturbed. To explain this with a schematic diagram, when no local short circuit occurs, the leakage flux due to the primary current is distributed as shown in Figure 3 (a), whereas when a local short circuit occurs, the leakage flux is distributed. The short-circuit current causes leakage flux that is locally concentrated around the short-circuit current generation site shown in FIG. 2(b).

Regarding this point, IEEJ Transactions VOL107-D, N
O.

1, '87, the leakage flux distribution at the time of a local short circuit in the winding was quantitatively studied. According to this, the leakage magnetic flux of the primary winding 13 flowing from the cylindrical windings 13a, 13b, 13c, and 13d shown in FIG. 4 is normally distributed as shown in FIG. The distribution of leakage magnetic flux when a local short circuit occurs at each part of A, B, and C of the cylindrical winding 13d is shown in the same figure (b).
The results are as shown in (d). When this is illustrated by the magnetic flux density distribution on the P-Q line shown in the same figure, the maximum distribution in the radial direction of the winding is as shown in Figure 6, and the maximum distribution in the axial direction is as shown in Figure 7. Become. As can be seen from this figure, when there is a local short circuit, the leakage flux distribution fluctuates more than when there is no local short circuit, so by installing the antenna 16 within the range covered by this magnetic flux distribution, it is possible to Leakage flux becomes interlinked with local short circuits. Specifically, primary winding 1
By installing the antenna 16 in the vicinity deviated by 200 degrees upward in the drawing from the center position of 3, leakage magnetic flux can be linked to the antenna 16. In this case, since the frequency of the leakage magnetic flux is the frequency of the power supply voltage, for example, 50 Hz, the measurement signal output from the antenna 16 and amplified by the amplifier passes through the first band pass filter 18. The bandpass filter 18 outputs pulsed light with a predetermined period to the optical fiber 20. Therefore, the signal processing device 21 can detect a local short circuit occurring in the primary winding 13 based on the pulsed light applied through the optical fiber 20.

Further, if a partial discharge occurs in the windings 13 and 14, it can be detected as follows. For example, primary winding 1
When a partial discharge occurs at 3, electromagnetic waves are output and interlink with the antenna 16. At this time, the frequency band of electromagnetic waves accompanying partial discharge is approximately IMHz to 100MHz.
Since the antenna 16 has a range of IM
A measurement signal whose main component is a frequency band from Hz to 100 MH2 is output. Then, the measurement signal is amplified by the amplifier 17 and then passes through one second band-pass filter, so that the second band-pass filter 19 outputs pulsed light with a predetermined period indicating this to the optical fiber 20. be done. Therefore, the signal processing device 21 can detect the occurrence of partial discharge in the windings 13 and 14 based on the pulsed light from the optical fiber 20.

In short, according to the above embodiment, since the occurrence of local short circuits and partial discharges can be detected using the sensor 15 alone, unlike the conventional example in which the occurrence of local short circuits and partial discharges must be detected individually, The overall configuration can be simplified.

FIG. 8 shows a second embodiment of the present invention. Hereinafter, the same parts as in the first embodiment will be given the same reference numerals, and the explanation will be omitted, and only the different parts will be explained. That is, the tank 11 is provided with sensors 15 corresponding to a plurality of locations in the height direction of the windings 13 and 14, and pulsed light from each sensor 15 is sent to the signal processing device 21. It has become.

By the way, the intensity of the electromagnetic waves measured by the antenna 16 is
Since there is a substantially proportional relationship with the distance from the occurrence point, it is possible to estimate the occurrence position of the local short circuit or the occurrence location of the partial discharge based on the strength of the measurement signal at each antenna 16. Therefore, it is possible to identify the location where a local short circuit or partial discharge occurs and quickly deal with it.

FIG. 9 shows a third embodiment of the invention.

That is, a plurality of sensors 15 are arranged at the same height on the outer peripheral surface of the tank 11, and pulsed light from each sensor 15 is output to the signal processing device 21.

In the case of this third embodiment, since a strong electromagnetic wave interlinks with the sensor 15 placed near the location where the local short circuit and partial discharge occur in the windings 13 and 14, the electromagnetic waves from the sensor 15 respond accordingly. The intensity of the pulsed light increases. Therefore, the signal processing device 1121 can specify the location where a local short circuit or partial discharge occurs in the radial direction of the winding based on the measurement signal.

FIG. 10 shows a fourth embodiment of the present invention.

That is, sensors 15 are provided corresponding to the U-phase, ■-phase, and W-phase of a three-phase transformer, and pulsed light from each sensor 15 is output to the signal processing device 21.

In the case of this fourth embodiment, when a local short circuit or partial discharge occurs in any of the phases, an electromagnetic wave is output from the winding corresponding to the location where the short circuit occurs, so the sensor 15 outputs pulsed light accordingly. is output. Therefore, the signal processing device 21 can identify the phase in which a local short circuit or partial discharge has occurred based on the pulsed light from the sensor 15.

In the second to fourth embodiments described above, the amplifier 17 and the first . Second bandpass filter 18.
19, but instead of this, amplifiers 17.19 are provided corresponding to the plurality of antennas 16, as shown in FIG.
1st. Second bandpass filter 18. ．． 19 may be provided, and these devices may be used in a time-sharing manner. In this case, it is desirable to protect the space between the antenna 16 and the amplifier 17 from electrical noise with a metal protective tube.

[Effects of the Invention] As is clear from the above description, the abnormality detection device for stationary induction equipment of the present invention can discriminate the frequency components of electromagnetic waves generated due to partial discharges and local short circuits in stationary induction equipment. Since the occurrence of partial discharge or local short circuit is detected based on this discrimination result, the number of detection elements can be reduced, simplifying the overall configuration, and improving reliability. It has excellent effects.

[Brief explanation of drawings]

1 to 7 show a first embodiment of the present invention. FIG. 1 is a block diagram of the entire transformer taken longitudinally, and FIG. 2 is a leakage flux diagram taken longitudinally of the transformer. Schematic diagram of the distribution. Figure 3 is a diagram schematically showing the leakage flux distribution. Figure 4 is 1.
Schematic diagram of the next winding, ′! Figure J5 is a schematic diagram of the leakage magnetic flux distribution shown longitudinally through the transformer, and Figures 6 and 7 are diagrams showing the relationship between the detection position and the magnetic flux density. 8 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention, FIG. 9 is a plan view of a transformer showing a third embodiment of the present invention, and FIG. 10 is a view corresponding to FIG. FIG. 11 is a schematic diagram of a three-phase transformer showing an IS4 embodiment, and is a diagram corresponding to FIG. 1 showing a modification of the present invention. and,
Figures 12 and 13 show conventional examples;
FIG. 2 is an overall block diagram, and FIG. 13 is a characteristic diagram showing the relationship between discharge charge amount and output voltage. In the figure, 11 is a tank, 12 is an iron core, 13 is a primary winding, 1
4 is a secondary winding, 15 is a sensor, 16 is an antenna (measuring device), 18 is a first band pass filter (discriminator), 19
21 is a second bandpass filter (discriminator), and 21 is a signal processing device (abnormality detection means).

Claims (1)

[Claims] 1. A measuring device for detecting abnormalities occurring in stationary induction equipment, which detects electromagnetic waves generated from windings, etc. in the stationary induction equipment and outputs a measurement signal indicating the frequency thereof, and this measuring device a discriminator that discriminates each frequency component generated due to a partial discharge and a local short circuit among the measurement signals from the
An abnormality detecting device for stationary induction equipment, comprising: abnormality detecting means for detecting occurrence of partial discharge or local short circuit based on the discrimination result by the discriminator.