JPH04175639A - Device for monitoring gas dissolved in oil and method thereof - Google Patents

Abstract

PURPOSE:To measure the quantity of oil extracted from oil in which it is dissolved, by connecting one and the other end sides of a gas sump, respectively to one and the other end sides of a gas detecting chamber through the intermediary of first and second valves. CONSTITUTION:First and second valves 10, 13 are at first deenergized so as to be opened. In this condition, by leaving them for a predetermined time, hydro gen gas in insulating oil in an oil chamber 4 is allowed to permeate through a gas permeable membrane 6 into a gas sump 5 in which hydrogen gas is accu mulated. After a predetermined time elapses, the first valve 10 is energized at first so as to be closed, and after one or two seconds elapses, the second valve 13 is energized to be closed. After leaving them for a predetermined time, a gas sensor 15 measures a quantity of hydrogen gas.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention uses gas dissolved in insulating oil in electrical equipment (
The present invention relates to a dissolved gas monitoring device for monitoring (dissolved gas in oil) and a method for monitoring dissolved gas in oil using the device.

[Prior Art] When an abnormality such as overheating or partial discharge occurs in oil-filled electrical equipment, the insulator decomposes and various gases are generated, and these gases dissolve into the insulating oil. There are many types of gases that can dissolve in insulating oil, but it is known that hydrogen gas will dissolve in insulating oil in most abnormal cases. Therefore, in order to detect internal abnormalities in oil-filled electrical equipment early and prevent accidents, a method is being used to quantitatively analyze hydrogen gas dissolved in insulating oil to determine the presence or absence of an abnormality.

Conventionally, when quantitatively analyzing dissolved gas in insulating oil, there are two methods: collecting a sample of oil at the location where the electrical equipment is installed, and bringing the sample oil to the location where the analyzer is installed, or analyzing the sample oil at the location where the electrical equipment is installed. The method used was to bring analytical equipment to the location for analysis.

However, since these methods require a great deal of time and effort for analysis, recently it has become common practice to attach monitoring devices for dissolved gases in oil directly to electrical equipment.

As a monitoring device for gas dissolved in oil that is directly attached to oil-filled electrical equipment, it includes an oil chamber filled with insulating oil of the electrical equipment, and a gas reservoir chamber that stores gas extracted from the insulating oil in the oil chamber through a gas permeable membrane. Some devices include a gas detection chamber connected to a gas reservoir chamber and a gas sensor disposed within the gas detection chamber. Conventional monitoring devices of this type are
As seen in No. 3441, the gas reservoir chamber and the gas detection chamber are connected through one pipe and a valve, and the dissolved gas in the oil is allowed to pass through the gas permeable membrane from the insulating oil into the gas reservoir chamber over a sufficient period of time. After extracting the gas, a valve is opened and the gas in the gas reservoir chamber is transferred by diffusion into the gas detection chamber, where a sensor detects a specific gas component (usually hydrogen).
I was trying to measure the amount of

When a gas and a liquid are brought into contact with each other through a gas permeable membrane for a certain period of time or more, each gas component exists separated into a gas side and a liquid side according to Henry's law. In this case, since the concentration in the liquid phase is proportional to the partial pressure in the gas phase, the amount of each gas component dissolved in the oil can be quantified by measuring the amount of each gas component on the gas side. be able to.

According to the above law, depending on the components and amounts of gases dissolved in the oil, and the gas components and amounts on the gas side (in a sealed gas reservoir), permeation occurs from the liquid side to the gas side or vice versa. The amount of each gas component that is added changes. If the insulating oil is new oil that has undergone deaeration treatment, there is almost no gas dissolved in it, so the air on the gas side (N2.02, C
O2, etc.) permeate to the oil side. Therefore, the pressure inside the gas reservoir chamber becomes negative after a certain period of time has passed.

Furthermore, since the sensor placed in the gas detection chamber generally measures the concentration of gas (in most cases, the concentration of hydrogen gas) in the atmosphere, a negative pressure inside the gas detection chamber causes a measurement error. Therefore, in the dissolved gas monitoring device disclosed in Japanese Patent Publication No. 63-3441, a hole is provided to communicate the inside of the gas detection chamber with the atmosphere, so that the inside of the gas detection chamber is kept at atmospheric pressure.

[Problems to be Solved by the Invention] In conventional dissolved gas monitoring devices, the gas reservoir chamber and the gas detection chamber were connected through only one pipe, so it was difficult for gas to flow from the gas reservoir chamber to the gas detection chamber. The movement of gas relied solely on the natural diffusion of gases. Therefore, it takes a long time to move the gas from the gas reservoir chamber to the gas detection chamber, making it impossible to perform measurements efficiently. In addition, with conventional devices, the gas detection chamber is always in communication with the atmosphere during measurement, so there is a risk that the extracted gas will diffuse into the atmosphere and escape, which may increase the measurement error of the amount of dissolved gas in the oil. Ta.

The purpose of the present invention is to improve the efficiency of measuring the amount of gas dissolved in oil by transferring gas from the gas reservoir chamber to the gas detection chamber in a short time, and to prevent the diffusion of gas from the gas detection chamber into the atmosphere. It is an object of the present invention to provide a monitoring device for dissolved gases in oil that can prevent measurement errors and reduce measurement errors, and a method for monitoring dissolved gases using the device.

[Means for Solving the Problems] The dissolved gas in oil monitoring device of the present invention includes an oil chamber filled with insulating oil of electrical equipment, and a gas storage system for storing gas extracted from the insulating oil in the oil chamber through a gas permeable membrane. The gas storage chamber includes a gas storage chamber, a gas detection chamber connected to the gas storage chamber, and a gas sensor disposed within the gas detection chamber. It is characterized in that it is connected to one end side and the other end side of the gas detection chamber via the valve and the second valve.

The first and second valves are configured by valves that can be switched between a closed state that communicates the gas detection chamber with the gas reservoir chamber, and an open state that communicates the gas detection chamber with the outside and cuts off communication between the gas reservoir chamber and the outside. is preferable.

Note that each of the first and second valves may be composed of a single valve element, or may be composed of a combination of a plurality of valve elements.

Preferably, the gas reservoir chamber is provided with one end thereof located above the other end, and the gas detection chamber is provided with one end thereof located above the other end.

Further, one end of the gas reservoir chamber is located above the other end, and one end of the gas detection chamber is located below the other end, and the gas detection chamber is positioned above the gas reservoir chamber. It is also good to place it at the bottom.

In the method for extracting dissolved gas in oil of the present invention, there is provided an oil chamber filled with insulating oil of electrical equipment, a gas reservoir chamber that stores gas extracted from the insulating oil in the oil chamber through a gas permeable membrane, and A gas detection chamber connected to the gas detection chamber and a gas sensor disposed within the gas detection chamber are provided, and the gas detection chamber is connected to one end side and the other end side of the gas reservoir chamber through a first valve and a second valve, respectively. Dissolved gas in oil monitoring devices are connected to one end and the other end of the chamber. It is configured to switch to an open state that cuts off communication between the reservoir chamber and the outside. Then, after keeping both the first and second valves open for a predetermined period of time to extract the dissolved gas in the insulating oil into the gas reservoir chamber, the first valve is closed and the interior of the gas reservoir chamber is expanded. Atmospheric pressure is established, and then the second valve is closed to move the gas in the gas reservoir chamber into the gas detection chamber.

[Function] As described above, when one end side and the other end side of the gas reservoir chamber are connected to one end side and the other end side of the gas detection chamber via the first valve and the second valve, respectively, the gas reservoir chamber Since a closed loop gas flow path can be formed from the gas flow path through the first valve, the gas detection chamber, and the second valve to the gas reservoir chamber, a gas flow flowing through the gas flow path can be generated by gas convection. . Therefore, gas can be moved from the gas reservoir chamber to the gas detection chamber in a short time, and the amount of extracted gas dissolved in the oil can be measured in a short time.

Furthermore, as described above, the first and second valves are switched between a closed state in which the gas detection chamber is communicated with the gas reservoir chamber and an open state in which the gas detection chamber is communicated with the outside and communication between the gas reservoir chamber and the outside is cut off. If two valves are configured, after both the first and second valves are kept open for a predetermined period of time to extract the dissolved gas in the insulating oil into the gas reservoir chamber, the first valve is first opened. After the second valve is brought into the closed state to bring the gas reservoir chamber to atmospheric pressure, the gas in the gas reservoir chamber can be moved into the gas detection chamber by closing the second valve. Therefore, measurements can be performed with the gas sensor under atmospheric pressure, and measurement errors can be reduced.

Furthermore, with the above configuration, the gas detection chamber is kept sealed during the measurement of the extracted gas dissolved in the oil, and the extracted gas does not diffuse into the atmosphere, thereby reducing measurement errors. can.

[Examples] Examples of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 shows an embodiment of the present invention, in which 1 is a tank for oil-filled electrical equipment such as an oil-filled transformer, 2 is insulating oil filled in the tank 1, and 3 is the tank 1. This is a drain valve connected to the oil drain port provided at the bottom. Reference numeral 4 denotes an oil chamber detachably connected to an oil drain port of the tank via a drain valve 3, and 5 is a gas reservoir chamber. The oil chamber is filled with insulating oil 2 introduced through the drain valve 3.

The oil chamber 4 and the gas reservoir chamber 5 are partitioned by a laminate of a gas permeable membrane 6 and a porous reinforcing plate 7.

The gas permeable membrane 6 is made of, for example, a fluororesin (about 50μ thick).
It is made of a film made of (trade name: Teflon, etc.). The reinforcing plate 7 is a porous plate that allows gas to freely pass in and out and has sufficient mechanical strength, and is made of, for example, a sintered body of stainless steel or the like.

In this example, the gas permeable membrane 6 is arranged with its membrane surface facing vertically, and one ends of gas conduits 8 and 9 are connected to the upper end (one end) and lower end (other end) of the gas reservoir chamber 5, respectively. ing. The other end of the gas conduit 8 is connected to the upper end (one end) of the gas detection chamber 12 via a first valve 10 and piping 11, and the other end of the gas conduit 9 is connected via a second valve 13 and piping 14. and is connected to the lower end (other end) of the gas detection chamber 12. A gas sensor 15 for detecting hydrogen gas is arranged within the gas detection chamber 12 .

The first valve 10 is a three-way electromagnetic valve, and when its excitation coil is energized, it enters a closed state that communicates the gas detection chamber 12 with the gas reservoir chamber 5, as shown by the broken line in the figure, and the first valve 10 is energized. When the gas detection chamber 12 is stopped, as shown by the solid line in the figure, the gas detection chamber 12 is communicated with the atmosphere, and the gas storage chamber 5 is switched to an open state in which communication is cut off with the atmosphere. The second valve 13 also consists of a similar three-way electromagnetic valve.

The gas sensor 15 used in this embodiment is a hydrogen gas sensor that utilizes changes in the conductivity of a semiconductor due to the attachment and detachment of negative gas from the surface of the semiconductor, and the heater is energized during the entire process from extraction of gas dissolved in oil to detection of gas. The temperature is maintained at a high temperature.

In the above embodiment, the sum of the volume inside the gas detection chamber 12 and the volume inside the pipe 11.14 is sufficiently larger than the sum of the volume inside the gas reservoir chamber 5 and the volume inside the gas conduits 8 and 9. It's getting smaller.

Next, a method for monitoring dissolved gas in oil using the above device will be explained. When measuring dissolved gas in oil, first of all,
Power to the first valve 10 and the second valve 13 is cut off to open both valves (the state shown by the solid line in the figure).

As a result, the gas reservoir chamber 5 is sealed, and the upper and lower portions of the gas detection chamber 12 are communicated with the atmosphere. This state is left for a predetermined period of time to allow hydrogen gas in the insulating oil in the oil chamber 4 to permeate into the gas reservoir chamber 5 through the gas permeable membrane 6, thereby storing hydrogen gas in the gas reservoir chamber 5. Extraction of this hydrogen gas usually takes a long time, from several tens of hours to 100 hours.

During this time, the gas sensor 13 is kept energized and its temperature is maintained at a high temperature required for measurement.

That is, the gas sensor 13 is always maintained in a state where it can perform measurements.

After a predetermined period of time has elapsed, first the first valve 10 is energized to close the valve 10, and after one to several seconds have elapsed, the second valve 13 is energized to close the valve 13. . When only the first valve 10 is closed for a short time, the inside of the gas reservoir chamber 5 is communicated with the atmosphere through the gas detection chamber 12 and the second valve 13, so that the pressure inside the gas reservoir chamber 5 is atmospheric pressure. Return to

After the second valve 13 is closed, the gas sensor 15 measures the amount of hydrogen gas after leaving it for a certain period of time (several tens of minutes to about one hour). When the second valve 13 is closed, a closed loop gas measurement system (gas flow path ), and gas is circulated through this measurement system by convection. In this embodiment, since the gas sensor 15 is maintained at a high temperature, gas convection is promoted and a gas flow that circulates through the gas measurement system is generated. Therefore, from inside the gas reservoir chamber 5 to the gas detection chamber 12.
The transition of gas inward takes place within a short time. Furthermore, in order to maintain high detection sensitivity of the gas sensor 15, it is necessary to prevent gas from accumulating around the gas sensor, but with the above configuration, gas flow can always be maintained around the gas sensor 15. Therefore, the detection sensitivity of the gas sensor can be maintained at a high level.

Even when the gas amount is measured by the gas sensor 15, gas is permeating through the gas permeable membrane 6 in the gas reservoir chamber 5, so theoretically the pressure inside the gas reservoir chamber 5 changes. As a result, the pressure within the gas detection chamber 12 also changes. However, the time required to measure the amount of gas is sufficiently shorter than the time required to extract the dissolved gas in the oil into the gas reservoir, so the pressure inside the gas reservoir changes due to gas permeation when measuring the amount of gas. is negligible and has almost no effect on the measurement.

In order to effectively generate the gas convection, it is necessary to connect the upper and lower end sides of the gas reservoir chamber 5 to the upper and lower end sides of the gas detection chamber 12 via valves 10 and 13, respectively, as in the above embodiment. It is preferable to connect it to

When the insulating oil 2 is introduced into the oil chamber 4 through the drain valve 3 at the lower part of the tank 1 as described above, the temperature of the insulating oil 2 is low and approximately equal to the temperature of the surrounding atmosphere. Therefore, the temperature inside the gas reservoir chamber 5 is also approximately the same as the ambient temperature. Therefore, the insulating oil 2 does not serve as a heat source that causes convection within the gas reservoir chamber 5. Therefore, the gas sensor is usually the only heat source that causes gas convection, and gas convection is performed smoothly.

On the other hand, in the above embodiment, when the temperature of the insulating oil 2 is high and convection is generated in the gas reservoir chamber 5 due to the temperature of the insulating oil, the convection generated in the gas reservoir chamber 5 due to the heat of the insulating oil is It acts to cancel the convection caused by the heat of the gas sensor 15, and the flow of gas is obstructed. In order to prevent this, as shown in FIG. The lower end of the detection chamber 12 (
The lower end (other end) of the gas reservoir chamber 5 is connected to the upper end (other end) of the gas detection chamber 12 via the second valve 13.
(one end). With this arrangement, the convection caused by the heat of the gas sensor and the convection caused by the heat of the insulating oil 2 are in a direction in which they are added to each other, so that the flow of gas can be promoted.

It goes without saying that the configuration shown in FIG. 2 can be adopted even when there is no risk of the temperature of the insulating oil 2 in the oil chamber 4 becoming high.

In the embodiment shown in FIG. 2, the upper end of the gas detection chamber 12 is connected to the lower end of the gas reservoir chamber 5 via the second valve 13, and the lower end of the gas detection chamber 12 is connected via the first valve 10. However, when the gas detection chamber 12 is arranged below the gas reservoir chamber 5, the gas detection chamber 12 is connected to the upper end of the gas reservoir chamber 5 by using another connection method. You may also connect it to For example, as shown in FIG. 3, the orientation of the gas detection chamber 12 is rotated 90 degrees,
One horizontal end of the gas detection chamber 12 is connected to the lower end of the gas reservoir chamber 5 via the second valve 13, and the other horizontal end of the gas detection chamber 12 is connected to the upper end of the gas reservoir chamber 5 via the first valve 10. It may also be connected to the side.

In each of the above embodiments, the first valve 10 and the second valve 13 are one valve element (three-way electromagnetic valve).
These valves are valves that switch between a closed state that communicates the gas detection chamber with the gas reservoir chamber, and an open state that communicates the gas detection chamber with the outside and cuts off communication between the gas reservoir chamber and the outside. Therefore, by combining a plurality of valve elements as shown in FIG. 4, it is also possible to configure the first valve 10 and the second valve 13 having similar functions. In the example shown in FIG. 4, the first valve 10 is controlled by valve elements 10A and 10B, which are electromagnetic valves that open and close gas flow paths in only one direction.
A second valve 13 is constituted by valve elements 13A and 13B, which are also made of electromagnetic valves.

Next, FIG. 5 shows an example of the configuration of a control circuit for the first and second valves (electromagnetic valves) 10 and 13 in the case where the series of measurement operations described above are automatically performed. In FIG. 5, T1~
T3 is a timer relay, R1゜R2 is an electromagnetic relay, and timer relays Tl, T2 and T3 each have a normally open contact Tla.
, has a normally closed contact T2b and a normally open contact T3a. Relay R1 also has normally open contacts R1al and Rla2, and relay R2 has normally open contacts R2al and R222. , S is the step down of the commercial AC power supply voltage E (100V),
This is a DC power supply circuit that rectifies and converts to DC voltage. The time limit of timer relay T1 is set to, for example, 100 hours, and the time limit of timer relay T2 is set to about 30 minutes.

Further, the time limit of timer relay T3 is set to one frame.

When this control circuit is energized, timer relay T1 and relay R1 are first excited. At the same time as this excitation, contact R1a
l, R1a2 closes. When 100 hours have passed after the start of energization, contact Tla of timer relay T1 closes, and timer relay T2. T3 and relay R2 are energized. At the same time as this excitation, contacts R2al and R2a2 close, and the first valve 10 is energized. As a result, the first valve 10
becomes closed.

Also, after the contact Tla closes, the timer relay T3 expires (1
seconds) have elapsed, contact T3! is closed and the second valve 1
3 is energized. This brings the second valve 13 into the closed state. When the time limit (30 minutes) of timer relay T2 elapses after contact Tla closes, contact T2b opens and power to timer relay Tl and relay R1 is cut off. This opens contact Tla and timer relay T2. The energization to T3 and relay R2 is cut off, and the measurement ends.

In the above embodiment, the gas conduits 8 and 9 are connected between the gas reservoir chamber 5 and the first and second valves 10 and 13.
The first valve 10 and the second valve 13 are connected by
and the gas detection chamber 12 are connected by pipes 11 and 14, but if the configuration shown in Fig. 1 is adopted, all or part of these gas pipes and pipes can be omitted and each valve can be connected. It can also be structured to be directly connected to a gas reservoir chamber or a gas detection chamber.

[Effects of the Invention] As described above, according to the present invention, one end side and the other end side of the gas reservoir chamber are connected to one end side and the other end side of the gas detection chamber through the first valve and the second valve, respectively. , it is possible to configure a closed loop gas flow path from the gas reservoir chamber to the gas reservoir chamber via the first valve, the gas detection chamber, and the second valve, and due to gas convection, the gas flow path A gas flow can be created that flows through. Therefore,
There is an advantage that the gas can be moved from the gas reservoir chamber to the gas detection chamber in a short time, and the amount of extracted gas dissolved in the oil can be measured in a short time.

Further, according to the invention described in claim 2, the valve switches between a closed state in which the gas detection chamber is communicated with the gas reservoir chamber and an open state in which the gas detection chamber is communicated with the outside and communication between the gas reservoir chamber and the outside is cut off. Since the first and second valves are configured according to The first valve is closed to bring the gas reservoir chamber to atmospheric pressure, and the second valve is closed to move the gas in the gas reservoir chamber into the gas detection chamber. Under atmospheric pressure,
Measurement errors can be reduced.

Furthermore, according to the present invention, the inside of the gas detection chamber is kept sealed during the measurement of extracted gas dissolved in oil, and the extracted gas does not diffuse into the atmosphere, which has the advantage of reducing measurement errors. There is.

[Brief explanation of drawings]

FIGS. 1 to 4 are block diagrams showing main parts of different embodiments of the present invention, and FIG. 5 is a connection diagram showing an example of the structure of a control circuit used in the embodiments of the present invention. 1... Tank for electrical equipment, 2... Insulating oil, 4...
Oil chamber, 5... Gas reservoir chamber, 6... Gas permeable membrane, 7.
... Reinforcement plate, 10... First valve, 12... Gas detection chamber, 13... Second valve, 15... Gas sensor.

Claims (5)

[Claims] (1) an oil chamber filled with insulating oil for electrical equipment; a gas reservoir chamber that stores gas extracted from the insulating oil in the oil chamber through a gas permeable membrane; and a gas detection chamber connected to the gas reservoir chamber; and a gas sensor disposed in the gas detection chamber, wherein one end side and the other end side of the gas reservoir chamber are connected to the gas detection chamber through a first valve and a second valve, respectively. A dissolved gas monitoring device in oil, characterized in that it is connected to one end side and the other end side. (2) The first and second valves have a closed state in which the gas detection chamber is communicated with the gas reservoir chamber, and an open state in which the gas detection chamber is communicated with the outside and communication between the gas reservoir chamber and the outside is cut off. The in-oil gas dissolved gas monitoring device according to claim 1, comprising a valve that switches between. (3) The gas reservoir chamber is provided with one end thereof located above the other end, and the gas detection chamber is provided with one end thereof located above the other end. The in-oil gas dissolved gas monitoring device according to claim 1 or 2. (4) The gas reservoir chamber is provided with one end thereof located above the other end, and the gas detection chamber is provided with one end thereof located below the other end. The in-oil gas dissolved gas monitoring device according to claim 1 or 2, which is arranged below the gas reservoir chamber. (5) an oil chamber filled with insulating oil for electrical equipment, a gas reservoir chamber that stores gas extracted from the insulating oil in the oil chamber through a gas permeable membrane, and a gas detection chamber connected to the gas reservoir chamber; a gas sensor disposed in the gas detection chamber, and the one end side and the other end side of the gas reservoir chamber are connected to one end side and the other end side of the gas detection chamber through a first valve and a second valve, respectively. The first and second valves are in a closed state in which the gas detection chamber is communicated with the gas reservoir chamber, and in a closed state in which the gas detection chamber is communicated with the outside and the gas reservoir chamber is connected to the outside. After extracting the gas dissolved in the insulating oil into the gas reservoir chamber by keeping both the first and second valves open for a predetermined period of time, first Dissolved gas in oil, characterized in that the first valve is closed to bring the gas reservoir chamber to atmospheric pressure, and then the second valve is closed to move the gas in the gas reservoir chamber into a gas detection chamber. Monitoring method.