JPH04369466A - Abnormality detector of gas filled electric machinery - Google Patents

Abstract

PURPOSE:To estimate and maintain the abnormal state of gas filled electric machinery by detecting the decomposed gas of insulated gas thermally decomposed by overheating or partial discharge by an optical detection means. CONSTITUTION:A decomposed gas detection element 14 composed of a material easy to react with decomposed gas is provided in an insulating gas passage so as to be freely detachable from the outside. When the decomposed gas detection element 14 is exposed to decomposed gas to receive corrosion, the transmissivity of the light applied to the detection element 14 is measured to be compared with a preset reference value by an electrical means and, when difference is generated between the reference value and the transmissivity, the generation of the decomposed gas is detected.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to gas-filled electrical equipment such as a gas insulated transformer, in which the main body of the electrical equipment is housed in a tank together with an insulating gas for insulation and cooling. The present invention relates to an abnormality detection device for gas-filled electrical equipment that detects the presence of decomposed gas caused by overheating, etc., and prevents accidents that may lead to loss of function or damage to the electrical equipment itself.

0002

[Prior Art] Conventionally, for example, in electrical equipment such as transformers, oil-immersed transformers have been the mainstream, in which an insulating oil with excellent insulation and cooling performance is sealed in a tank housing the equipment body. However, if this oil-immersed transformer malfunctions due to abnormal overheating, the insulating oil may catch fire or explode, causing secondary disasters such as fire to surrounding buildings. In particular, with the increase in demand for electricity in recent years, electrical equipment for receiving and transforming power is often installed in the basements of buildings around urban areas due to the difficulty of securing installation locations. Due to changes in the environment, there is a social demand for products with excellent safety without the risk of fire outbreaks or environmental destruction.

Recently, however, gas-insulated transformers have been adopted in place of the oil-immersed transformers, which are less likely to cause fires, are smaller and lighter than oil-immersed cooling systems, and are superior in disaster prevention and reliability. It's starting to happen. In this gas insulated transformer, an insulating gas such as SF6 gas (sulfur hexafluoride gas) is filled as a cooling medium in place of the insulating oil in a tank that houses the main body of the device, and is used to insulate and cool the main body of the device. ing. Even if the temperature inside the tank becomes abnormally high due to a malfunction or the like, there is almost no risk of a fire breaking out, and there is little negative impact on the surrounding environment, making it ideal for installation in urban areas or underground buildings.

On the other hand, from the viewpoint of stable supply of electric power, it is necessary to avoid stopping the operation of electrical equipment such as transformers due to accidents. However, in the case of transformers, for example, leakage magnetic flux may cause eddy currents to flow in the structural members that make up the tank or the equipment body, causing localized abnormal overheating, heat generation due to incomplete contact between conductor connections, and even heat generation. There are many causes of abnormalities, such as insulation deterioration caused by partial discharge and heat generation due to aging of insulators, and if these abnormalities expand and progress, they can lead to major accidents and cause power supply interruptions.

[0005]

[Problems to be Solved by the Invention] As mentioned above, early discovery or detection of internal abnormalities in electrical equipment is extremely important from the perspective of preventing major accidents involving electrical equipment. For example, if an internal abnormality occurs in the main body of the electrical equipment, the internal abnormality may cause an overheated winding conductor (CU
) and an insulating gas such as SF6 gas react directly to form SF4.
Since decomposed gases such as gases are generated, by checking the presence or absence of these decomposed gases, it is possible to easily know whether or not the main body of the device is malfunctioning. Therefore, the same applies to gas insulated transformers that use insulating gas such as SF6 gas, and it is necessary to constantly or periodically detect and analyze the insulating gas in order to determine whether an abnormality has occurred in the equipment itself. be. However, conventionally, when detecting the decomposed gas, for example, gas is sampled from inside the tank of a transformer, and a gas chromatograph, a mass spectrometer, etc. are used to detect whether the decomposed gas is contained in the sampled gas. Anomalies in the device itself were detected by analyzing whether or not the device was present, but there were the following problems.

(1) When checking whether there is an internal abnormality in the main body of the device, the gas in the tank is first collected into a cylinder, and the gas is transported to a place where an analyzer such as a gas chromatograph is located to detect the presence or absence of decomposed gas. As a result, detection was time-consuming and labor-intensive, and if the abnormality of the equipment continued to develop during this time, there was a problem in that it would be impossible to predict and maintain a major equipment accident. (2) Furthermore, the gas sampling work described above must be carried out with the transformer's live wires, which is extremely dangerous, and the amount of gas sampled is very large.
Because the gas pressure in the tank decreases, there is a natural limit.As a result, when the scale of the abnormality is small or in the early stages of an abnormality, the detection sensitivity of the analyzer is often below, and the abnormality can be detected early. There was also the problem that it could not be detected.

In view of the above-mentioned problems, the present invention continuously monitors decomposed gas generated by overheating of insulating gas and partial discharge, etc. when necessary, thereby detecting minor abnormalities such as those in the early stages of abnormality in electrical equipment. An object of the present invention is to provide an abnormality detection device for gas-filled electrical equipment that can quickly and reliably detect the abnormal state of the electrical equipment at an early stage and enable early prediction and maintenance of the abnormal state of the electrical equipment.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a tank containing a device main body, and an SF
A gas abnormality detection device is installed in the middle of the gas distribution pipe connected to the cooling device that cools the insulating gas such as 6.
This gas abnormality detection device includes a decomposed gas detection element made of a material that easily reacts with the decomposed gas arranged in the gas distribution pipe, and a light emitting element and a light receiving element arranged outside the gas distribution pipe in a direction perpendicular to the detection element. element, an optical fiber for guiding light, an operational amplifier circuit that operationally amplifies the minute signal output of the light received by the light receiving element, and a standard that outputs a signal corresponding to a preset reference value. The output from the signal generation circuit and the operational amplifier circuit is compared with the output from the reference signal generation circuit, and if the output from the operational amplifier circuit exceeds the output from the operational amplifier circuit, the comparison circuit outputs the output signal and the output from the comparison circuit is For example, it is characterized by being configured to include a signal processing circuit that performs digitization and data processing, and a device that displays (alarms) an abnormality in gas-filled electrical equipment by inputting the processed signal.

[0009]

[Operation] According to the present invention, as a decomposition gas detection element disposed in a gas distribution pipe, a decomposition gas detection element is used to detect decomposed gases generated by abnormal conditions such as partial discharge, etc. that occur in gas-insulated electrical equipment filled with an insulating gas such as SF6 gas. Materials that react extremely easily with decomposed gases such as SO2 and SF4, such as silica (S
Using a glass substrate based on IO2) alone,
Copper (Cu), aluminum (
The surface of the detection element itself changes due to corrosion due to chemical changes that occur when the decomposition gas detection element, which has a metal vapor deposited film formed by vapor deposition of a metal material such as Al) or chromium (Cr), comes into contact with the decomposition gas. SF6 gas, etc. It is characterized by being able to quickly and reliably detect the occurrence of abnormalities such as overheating and partial discharge in an insulating gas.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is implemented in a gas insulated transformer will be described below with reference to FIGS. 1 to 4. In Figure 2, 1 is a tank of a gas insulated transformer, and there is an iron core 2 inside.
A transformer main body 6 comprising a winding 3 wound around the iron core 2 and clamping clamps 4 and 5 for tightening the upper and lower parts of the iron core 2 is housed. Further, in this tank 1, together with the transformer body 6, an inert and nonflammable insulating gas such as SF6 gas for insulation and cooling is sealed at a predetermined pressure. Reference numeral 7 designates an insulating gas cooling device installed between gas distribution pipes 8 and 9 that are connected to the inside of the tank 1 and installed above and below the side wall of the tank 1. A gas blower 10 guides the gas from the upper part of the tank 1 through the upper gas distribution pipe 8 to the cooling device 7.
After cooling here, it passes through the lower gas distribution pipe 9 to the tank 1.
The transformer main body 6 is cooled by circulating the water inside the transformer body 6. 11 and 12 are attached to the top surface of the tank 1,
This is a bushing for pulling out the lead wire from the winding 3 to the outside.

Next, in FIG. 1, reference numeral 13 denotes a gas abnormality detection device inserted through a valve X in the middle of the lower gas distribution pipe 9, for example, between the tank 1 and the gas blower 10, and its outline will be explained below. do. In Figures 1, 3, and 4, 14
is a decomposition gas detection element, and this decomposition gas detection element 14 is
It exists abundantly in the earth's crust and is a material for glass.
Silica (SIO2) reacts extremely well with cracked gas.
) and the glass substrate 1
Similar to 4a, copper (Cu) is extremely reactive with decomposition gas.
, aluminum (Al), chromium (Cr), etc., is deposited on a glass substrate 14a to a required thickness (thickness that allows light to pass through to a certain extent). Then, the decomposition gas detection element 1
4, for example, as shown in FIGS. 1 and 3, the insulating gas flow direction (FIG. 1
It is attached so that it can be taken out from the lower gas flow pipe 9 in parallel with the arrow direction) and with the metal vapor deposited film 14b facing upward. That is, as shown in FIG. 3, one end of the decomposition gas detection element 14 parallel to the axial direction of the inner circumferential surface of the lower gas flow pipe 9 is fitted onto the retaining plate 15 using a fixing member such as a bolt. This retaining plate 15 is supported on a mounting plate 16 on the outside of the lower gas distribution pipe 9, and a support plate 18 having a through hole 17 through which the retaining plate 15 is inserted is provided on the lower gas distribution pipe 9 side. The support plate 18 is fitted into the fitting hole 19 and fixed by welding or the like, and the inner peripheral surface of the gas flow pipe 9 corresponding to the support plate 18 has an engagement member with which the other end of the cracked gas detection element 14 engages. A locking plate 21 with a matching groove 20 installed horizontally is fixed, and when installing the cracked gas detection element 14, the detection element 14 is inserted into the lower flow pipe 9 through the through hole 17 of the support plate 18 and engaged. engaging the engagement groove 20 of the stop plate 21, and engaging the holding plate 15 in the through hole 17 of the support plate 18;
In this state, by bolting the mounting plate 16 to the support plate 18 via a sealing member such as an O-ring, the decomposed gas detection element 14 can be removed and placed horizontally at the center of the thick diameter portion 9a in the lower gas flow pipe 9. Can be mounted on a shelf.

Next, reference numeral 22 shown in FIG.
For example, a light emitting element equipped with a light source such as a light emitting diode or a laser, disposed orthogonally to the metal vapor deposited film 14b side of No. 4,
The light emitted from the light emitting element 22 is guided to the optical fiber 24 inserted into the lower gas flow pipe 9 via an airtight packing 23, and is directed from the open end face toward the metal vapor deposited film 14b of the decomposition gas detection element 14. irradiated. Reference numeral 25 denotes a light-receiving element made of, for example, a phototransistor, which is disposed below the large-diameter portion 9a of the lower gas flow pipe 9 so as to face the light emitting element 22.
An optical fiber 24 inserted into the distribution pipe 9 via a
a, and receives light transmitted through the decomposition gas detection element 14 and guided from the open end surface of the optical fiber 24a for optical detection. 26 is an operational amplifier circuit for electrically operationally amplifying the detection signal received by the light receiving element 25. Reference numeral 27 denotes a reference signal generation circuit that outputs a reference signal for setting the decomposition gas generation reference value with a constant pulse.The setting value of the output reference signal (reference value) is determined by the decomposition gas detection element 14 used It is configured so that it can be changed arbitrarily. 28 is a comparison circuit, and operational amplifier circuit 2
6 and the output from the reference signal generation circuit 27, and if the output from the operational amplifier circuit 26 differs from the output from the reference signal generation circuit 27 (that is, the amount of decomposition gas generated is (If it exceeds the preset standard value)
The device is configured to output an output signal. 29 denotes a signal processing circuit for digitizing and data processing the signal output from the comparison circuit 28;
is a display (alarm) device activated by the output from the signal processing circuit 29.

As explained above, the gas abnormality detection device 13 of the present invention basically uses a glass substrate 14 made of silica.
A decomposed gas detection element 14 is provided with a metal vapor deposited film 14b deposited on it and horizontally supported within the lower gas flow pipe 9, and light is guided by optical fibers 24 and 24a to irradiate the decomposed gas detection element 14. , a light-emitting and light-receiving element 22, 25 that receives the light transmitted through the detection element 14, an operational amplifier circuit 26 that amplifies the received signal, and a reference signal generation circuit 27 that sets a reference value for the generation of decomposition gas. Consisting of a comparison circuit 28 that compares the received light signal and the reference signal and outputs a signal when a difference occurs, and a signal processing circuit 29 that processes the output signal from the comparison circuit 28 and outputs it to the display device 30. has been done.

Next, the operation of the gas abnormality detection device 13 will be explained. During the operation of a gas insulated transformer, for example, the insulation coating of the silicon steel strip that makes up the iron core may be damaged by vibrations during transportation, resulting in abnormal local overheating of the iron core 2.
SF
6 When the temperature reaches the temperature at which an insulating gas such as gas decomposes, or when a spark caused by partial discharge etc. directly reacts with an insulating gas such as SF6 gas, SO2, SF4
decomposed gases such as As shown in FIGS. 2 and 3, the decomposed gas circulates in the order from inside the tank 1 to the upper gas distribution pipe 8 → the cooling device 7 → the lower gas distribution pipe 9 → the inside of the tank 1. When flowing through the gas distribution pipe 9, the decomposed gas passes through the decomposed gas detection element 14 as shown in FIG.
You will be in direct contact with. As a result, the detection element 14
(metal vapor deposited film 14b part) and back surface (glass substrate 1
4a (portions not having the metal vapor deposited film 14b) are gradually eroded by a chemical reaction caused by contact with the decomposition gas. That is, the surface shape of the decomposition gas detection element 14 changes compared to before being exposed to the decomposition gas. This is because the glass substrate 14a and the metal vapor deposited film 14b themselves are made of materials that easily react with decomposition gas. Therefore, the transmittance through the detection element 14 of the light projected from the light emitting element 22 and irradiated onto the decomposed gas detection element 14 also changes as the surface shape changes. By utilizing this change in transmittance, it is possible to detect the occurrence of an abnormality, such as partial discharge or local abnormal heating, within the tank 1, for example.

Next, regarding the change in transmittance in the decomposition gas detection element 14, for example, using a decomposition gas detection element 14 in which a copper vapor deposited film 14b is formed on a glass substrate 14a, the change in transmittance is determined at a constant wavelength interval. The results of spectrum measurement and experimental verification of the transmittance will be explained. In FIG. 1, light transmitted through the detection element 14 due to the generation of decomposed gas is received by a light receiving element 25, amplified by an operational amplifier circuit 26, and input to a comparison circuit 28. On the other hand, the reference signal generation circuit 27 always outputs a reference value (indicates a reference signal corresponding to the transmittance of light transmitted through the decomposed gas detection element 14 measured when no decomposed gas is present). A reference signal is input to a comparison circuit 28, and the comparison circuit 28 compares both input signals. If the input from the operational amplifier circuit 26 differs from the reference signal, the comparison circuit 28 sends a signal to the signal processing circuit. 29, the display device 30 displays that the decomposed gas exceeds the standard value. This is shown in FIG. 8 as a metal vapor deposited film 14b.
To explain the spectrum measurement results in the case of the decomposition gas detection element 14 using copper as the material, the line indicated by A in the figure is the transmittance (reference value) measured before exposure when no decomposition gas is generated. , B is a diagram obtained by measuring the transmittance of light transmitted through the detection element 14 (when decomposed gas is generated) when exposed to decomposed gas, and is shown in FIG.
As shown in the figure, it was found through experiments that when copper was used for the metal vapor deposited film 14b, the transmittance increased when decomposition gas was generated. This is caused by the decomposition gas causing the metal vapor deposited film 14 to
It is presumed that the surface of b has been eroded, for example, and the transmittance has changed mainly due to a change in the surface condition. Based on the above experimental results, if the reference value A is set as the point in time when the decomposed gas detection element 14 is attacked by the decomposed gas within the allowable range, the time B when decomposed gas is generated becomes the reference value A, as shown in FIG.
By displaying this on the display device 30 or issuing an alarm when the value exceeds 1, an abnormal state such as a partial discharge in the tank 1 can be accurately detected. Also, by changing the set value of reference value A,
Since it is possible to detect minute amounts of decomposed gas at the stage of a minor failure sign, it is possible to regularly grasp the abnormal state of electrical equipment filled with insulating gas such as SF6 gas, and also to predict it.・Maintenance can be performed easily and reliably at all times.

Next, a schematic configuration of a second embodiment of the gas abnormality detection device according to the present invention will be described with reference to FIG. 5, only the parts that are different from the configuration of the first embodiment of the present invention shown in FIG. Gas abnormality detection device 13 of the second embodiment shown in FIG.
A detects the occurrence of an abnormality in the tank 1 by utilizing a change in the light reflected by the decomposition gas detection element 14, that is, a change in reflectance, out of the light irradiated onto the decomposition gas detection element 14. be. In FIG. 5, the light emitting element 22 includes an optical fiber 24, a prism 31, an optical fiber 2
The open end of the optical fiber 24a, which is connected to the thick diameter portion 9a of the lower gas distribution pipe 9 through the fiber 4a and protrudes into the thick diameter portion 9a of the optical fiber 24a, is connected to the metal vapor deposited film 14 of the decomposed gas detection element 14.
It is attached to the thick diameter portion 9a facing oppositely to b. on the other hand,
The light receiving element 25 is connected to the large diameter portion 9a of the lower gas flow pipe 9 via optical fibers 24a and 24b, facing the metal vapor deposited film 14b of the decomposed gas detection element 14. Next, in the second embodiment of the present invention, the degree of generation of decomposition gas is measured using the decomposition gas detection element 14, which has a copper vapor deposited film 14b formed on the surface of the glass substrate 14a, as in the first embodiment.
We will explain an example of an experiment conducted by In Figure 5,
When the light emitted from the light emitting element 22 is irradiated onto the decomposition gas detection element 14 using the prism 31, most of the irradiated light is transmitted through the decomposition gas detection element 14. However, a part of the irradiated light is reflected by the detection element 14, received by the light receiving element 25, operationally amplified by the operational amplifier circuit 26, and output to the comparison circuit 28. On the other hand, from the reference signal generation circuit 27a, a reference signal corresponding to the reflectance of light reflected from the decomposed gas detection element 14 measured when no decomposed gas is present is inputted to the comparison circuit 28. The comparison circuit 28 compares the two inputs, and when the input from the operational amplifier circuit 26 differs from the reference signal, outputs an output signal to the signal processing circuit 29 and displays the display device 30.
indicates that the decomposition gas exceeds the standard value.

To explain this with the spectrum measurement results shown in FIG. 9, the line C in the figure shows the light reflectance (reference value) before the decomposed gas is generated, and the line D shows the reflectance of the decomposed gas detection element. The reflectance of the light reflected from each detection element 14 (when decomposition gas is generated) is measured when 14 is exposed to decomposition gas. It was confirmed through experiments that the reflectance D of light when gas is generated is lower than the reflectance C when no gas is generated. This is because the surface condition of the decomposed gas detection element 14 changes due to the generation of decomposed gas,
This shows that the light transmittance has increased as in the first example, and also in this second example, the decomposed gas detection element 1
4 was confirmed to have been eroded by decomposition gas. That is, in the first and second embodiments of the present invention, if the detection element 14 is eroded by the decomposed gas, the increase or decrease in light transmittance and reflectance are necessarily inversely proportional, and therefore, either of these decomposition It was confirmed that the gas detection means could also detect the generation of decomposed gas. As a result, in the second embodiment, the setting of the reference value C is made variable as in the first embodiment, so that the time point at which generation of cracked gas is detected can be arbitrarily set, and as a result, the reference value C When a difference occurs between the time D and the time D when decomposed gas is generated, an abnormality in the tank 1 can be reliably detected by displaying it on the display device 30.

Next, FIG. 6 shows a schematic configuration of a third embodiment of the gas abnormality detection device according to the present invention, which is different from the configuration of the first embodiment of the present invention shown in FIG. 1 and the second embodiment shown in FIG. Only parts will be explained. The gas abnormality detection device 13b of the third embodiment shown in FIG.
4 is irradiated with light from the light emitting element 22, a change in the light transmitted from the detection element 14 and a change in the light reflected,
That is, the occurrence of an abnormality within the tank 1 is detected by utilizing the change caused by adding up the transmittance and reflectance of light. In FIG. 6, the light emitting element 22 is connected to the thick diameter portion 9a of the lower gas flow pipe 9 via the optical fiber 24, the prism 31, and the optical fiber 24a, as in the second embodiment. The opening end surface projecting inward is attached to the thick diameter portion 9a so as to face the metal vapor deposited film 14b of the decomposed gas detection element 14. On the other hand, as shown in FIG. 6, a light-receiving element 25 that receives the light transmitted from the decomposed gas detection element 14 is placed above the thick diameter part 9a of the lower gas flow pipe 9, facing oppositely to the prism 31. It is connected via an optical fiber 24b that is airtightly inserted into the thick diameter portion 9a, and the output end of the light receiving element 25 is connected to an operational amplifier circuit 26a. Further, as shown in FIG. 6, the light receiving element 25a that receives the light reflected from the decomposed gas detecting element 14 is located opposite to the metal vapor deposited film 14b of the decomposed gas detecting element 14.
The optical fibers 24a and 24d are connected to the lower side of the thick diameter part 9a with a packing 23a, and are airtightly inserted into the thick diameter part 9a, and the output end thereof is connected to the operational amplifier circuit 26a as well as the light receiving element 25. Connected.

Next, an example will be described in which the degree of generation of decomposed gas in the third embodiment was tested using the same decomposed gas detection element 14 as in the first embodiment. In FIG. 6, when the light from the light receiving element 22 is irradiated onto the detecting element 14 through the prism 31, the light passes through the detecting element 14 and a part of it is reflected.
5, 25a, and is operationally amplified by the operational amplifier circuit 26a in a state where the transmittance and reflectance are summed, and then sent to the comparison circuit 2.
Output to 8. On the other hand, from the reference signal generation circuit 27b,
A reference signal corresponding to the sum of the transmittance and reflectance of the light transmitted and reflected from the decomposed gas detection element 14 measured at the time when no decomposed gas is present is detected by the comparison circuit 28.
The comparator circuit 28 compares the inputs,
When the input from the operational amplifier circuit 26a differs from the reference signal, an output signal is output to the signal processing circuit 29, and the display device 30 displays that the decomposed gas exceeds the reference value.

To explain the above results using the spectrum measurement results shown in FIG. 10, the line marked E in the figure shows the state before the decomposed gas is generated, and the line marked F shows the state before the decomposed gas detection element 14 is exposed to the decomposed gas. The sum of the transmittance and reflectance of the light transmitted and reflected from the detection element 14 is shown, and as can be seen from these diagrams E and F, decomposed gas is generated. It has been confirmed through experiments that the total value F of light transmittance and reflectance is smaller than the total value E before the decomposition gas is generated. This was found to be due to the detection element 14 itself being eroded by the decomposition gas, similar to the two examples above. As described above, in the first to third embodiments of the present invention, the surface state of the decomposition gas detection element 14 changes when exposed to decomposition gas, and this changes the transmittance and reflection of light irradiated onto the detection element 14. It was confirmed that there is always an increase/decrease relationship with the rate, and that it is possible to detect the presence of decomposed gas, that is, the generation of decomposed gas, based on this result. Depending on the degree of detection of this decomposed gas, it is possible to detect the occurrence of an abnormality in an insulating gas such as SF6 gas at a minor failure precursor stage before an accident occurs. In addition, in the third embodiment, the reference value E
The setting is variable as in the first and second embodiments, and if there is a difference between this reference value E and the time F when cracked gas is generated,
The display on the display device 30 is the same as in the previous embodiment.

Next, experimental results in an example in which the decomposed gas detection element 14 uses, for example, only the glass substrate 14a will be explained with reference to the spectrum measurement results shown in FIGS. 11 to 13. FIG. 11 shows a comparison between the light transmittance b when decomposed gas is generated and the transmittance a when no decomposed gas is generated, using a decomposed gas detection element (not shown) consisting only of a glass substrate 14a. Similarly to FIG. 11, FIG. 12 shows the reflectance d of light from a decomposed gas detection element (only the glass substrate 14a, not shown) when decomposed gas is generated, and the reflectance c when no decomposed gas is generated. Furthermore, FIG. 13 shows the sum value f of the transmittance b and reflectance d of light from the decomposed gas detection element (only the glass substrate 14a) (not shown) when decomposed gas is generated, and
It shows a comparison between the value e, which is the sum of the transmittance a and the reflectance c when no occurrence occurs, and is shown in FIG. 1 above.
1 to 13, even in the decomposed gas detection element consisting only of the glass substrate 14a, the glass substrate 14a
Silica glass (SiO
2), when decomposed gas is generated in the tank 1, the glass substrate 14a exposed to the decomposed gas
The surface condition changes due to a chemical reaction with decomposed gas, which increases the light transmittance or decreases the reflectance. Based on the changes, abnormal occurrences such as partial discharge can be detected in insulating gas such as SF6 gas.

As described above, in the present invention, the ratio of transmission and reflection of light irradiated to the decomposition gas detection element 14, which is relatively likely to react with decomposition gas, is constantly detected, and this is set to a preset reference value. Since it is possible to easily detect abnormal conditions in the tank 1 at a relatively minor point in time compared to the above, it is possible to quickly and reliably predict and maintain abnormal conditions in electrical equipment filled with insulating gas such as SF6 gas. be able to.

Next, the detection element 14 is eroded by the decomposition gas.
However, when it can no longer perform its function, it needs to be replaced. In that case, first stop the cooling device 7, then
After closing valve X in Fig. 2, in Fig. 3, attaching plate 1
6 and the support plate 18, and remove the mounting plate 1 from the through hole 17.
6, by removing the used decomposition gas detection element 14 and fixing the mounting plate 16 equipped with a new detection element 14 (or only the decomposition gas detection element 14 may be replaced) to the support plate 18, This is to replace the decomposed gas detection element 14 under live line conditions. Further, FIG. 7 shows another installation state of the cracked gas detection element 14, in which a U-shaped bypass pipe 35 is connected to the lower gas distribution pipe 9 via a valve Y in the middle of the pipe so that it can communicate with the U-shaped bypass pipe 35. A cracked gas detection element 14 is arranged in the large diameter portion 35a of the bypass pipe 35,
When replacing the detection element 14 in this case, after closing the valve Y, replace the decomposed gas detection element 14 with a new one using the above-described replacement procedure. In this case, the replacement work can be done by closing the bypass pipe 35 with the valve Y, so that the cracked gas detection element 14 can be replaced without stopping the cooling device 7 of the electric equipment. In addition, Figures 1 and 5
Reference numeral 36 shown in FIG. 7 is a replenishment pipe for insulating gas such as SF6 gas, and the replenishment pipe 36 is used to vacuum-fill the insulating gas when replacing the decomposed gas detection element 14.

[0024]

Since the present invention is constructed as described above, it has the following effects. (1) In the present invention, the decomposed gas detection element is formed using a material that relatively easily reacts with the decomposed gas generated when an insulating gas such as SF6 gas is thermally decomposed or decomposed due to partial discharge, etc. Therefore, if an abnormality such as overheating or partial discharge occurs in a gas-filled electrical device, the decomposition gas detection element will react with the decomposition gas and its surface state will change relatively quickly, so that the light emitting element will not be detected. By taking advantage of the fact that the transmittance of light changes rapidly when it is irradiated with light, and constantly monitoring changes in this light,
Abnormalities in gas can be detected quickly and reliably at a minor stage. (2) Also, the decomposed gas detection element is horizontally mounted and supported in the hollow part of the insulating gas flow path parallel to the gas flow direction so as not to obstruct the flow of the insulating gas. When gas is generated, any part can come into contact with the decomposed gas, making it possible to detect the decomposed gas at an early stage.In addition, even if it is attacked by the decomposed gas and needs to be replaced, it is possible to prevent the insulating gas from flowing. Since it is constructed so that it can be easily removed and replaced from the outside of the road, the replacement work can be carried out smoothly and efficiently without adversely affecting the electrical equipment. (3) Furthermore, when detecting abnormalities in gas-filled electrical equipment, as mentioned above, since the decomposed gas detection element uses a material that easily reacts with decomposed gas, optical detection means can be used, for example. , it becomes easy to measure transmittance and reflectance, and it becomes possible to detect decomposed gas quickly and reliably within a short period of time from the time of generation, thereby minimizing abnormalities in gas-filled electrical equipment. It can be predicted and maintained within a short period of time. (4) Moreover, the abnormality detection device for gas-filled electrical equipment of the present invention uses a ubiquitous silica-based material as the base material, and also uses a general-purpose metal as the material of the metal vapor deposition film. , the decomposition gas detection element can be easily formed, and the decomposition gas detection means only needs to optically detect the degree of light acting on the detection element. The abnormality detection device not only maintains its detection performance well, but also eliminates the trouble of extracting insulating gas from the tank for detection, and eliminates the need for high-precision measuring instruments and analyzers. It has a simple configuration and can be manufactured economically.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a gas abnormality detection device of the present invention.

FIG. 2 is a vertical cross-section showing a main part of a gas-filled electrical device equipped with the gas abnormality detection device of the present invention.

FIG. 3 is a sectional view showing how the decomposition gas detection element is attached.

FIG. 4 is a longitudinal cross-sectional view of a decomposed gas detection element.

FIG. 5 is a schematic configuration diagram of a gas abnormality detection device according to another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a gas abnormality detection device according to still another embodiment of the present invention.

FIG. 7 is a sectional view showing another mounting state of the decomposition gas detection element.

FIG. 8 is a graph of spectrum measurement results showing a comparison of light transmittance before and after generation of decomposed gas in a decomposed gas detection element having a metal vapor deposited film using copper.

FIG. 9 is a diagram of spectrum measurement results comparing light reflectance.

FIG. 10 is a diagram of spectrum measurement results showing a comparison of the sum of light transmittance and reflectance.

FIG. 11 is a diagram of spectrum measurement results showing a comparison of light transmittance before and after generation of decomposed gas in a decomposed gas detection element made of only a glass substrate.

FIG. 12 is a diagram of spectrum measurement results comparing light reflectance.

FIG. 13 is a diagram of spectrum measurement results showing a comparison of the sum of light transmittance and reflectance.

[Explanation of symbols]

1 Tank 6　Transformer body 9 Lower gas distribution pipe 13 Gas abnormality detection device 14 Decomposition gas detection element 15 Holding plate 16 Mounting plate 18 Support plate 20 Engagement groove 21 Locking plate 22 Light emitting element 24 Optical fiber 25 Photo receiving element 26 Operational amplifier circuit 27 Reference signal generation circuit 28 Comparison circuit 29 Signal processing circuit 30 Display device

Claims (4)

[Claims] 1. A decomposed gas detection element made of a material that easily reacts with decomposed gas, removably horizontally supported and supported in a hollow part of a gas flow pipe, and a decomposed gas detection element facing opposite to the decomposed gas detection element on the outside of the gas flow pipe. a light-emitting element and a light-receiving element arranged via a light transmission means such as an optical fiber, and when the light of the light-emitting element is transmitted or reflected by a decomposition gas detection element, this light is detected by the light-receiving element, and , an amplifying means for operationally amplifying the signal detected by the light receiving element, a comparing means for comparing the output from the amplifying means with a preset reference value, and further an amplifying means for operationally amplifying the signal detected by the light receiving element; An abnormality detection device for gas-filled electrical equipment, characterized in that it is equipped with a display means for displaying. 2. The cracked gas detection element has one end removably engaged with a locking plate provided in the gas flow pipe, and the opposite end fitted into a retaining plate, which retains the retaining plate. It is fixed to a mounting plate on the outside of the gas distribution pipe, and the decomposed gas detection element is mounted horizontally and suspended on the locking plate in the fitting hole drilled in the gas distribution pipe, and the mounting plate is installed in an airtight manner. 2. The abnormality detection device for gas-filled electrical equipment according to claim 1, wherein the device is removably attached to the gas-filled electrical equipment. 3. The decomposed gas detection element made of a material that easily reacts with decomposed gas is formed by depositing a glass substrate mainly made of silica or a metal material that easily reacts with decomposed gas on the glass substrate. An abnormality detection device for gas-filled electrical equipment according to claim 1. 4. The light detected by the light receiving element has one of the transmittance or reflectance of the light transmitted through the decomposed gas detection element, or the sum of the transmittance and the reflectance. The abnormality detection device for gas-filled electrical equipment according to claim 1.