JPS59111044A - Apparatus for measuring gas in oil of oil contained insulating electric device - Google Patents

Abstract

PURPOSE:To make it possible to measure a desired kind of gas, by analyzing gas permeated through a high-molecular permeable membrane by an infrared type gas analyser. CONSTITUTION:As a permeable membrane 6, one which is impervious to insulating oil but pervious to only gas dissolved in said oil may be used. In addition, because a certain time is required before the gas dissolved in the oil is permeated into a gas chamber through the permeable membrane 6 to reach equilibrium, the area of the opening part of the gas chamber 7 is made large and the volume of the gas chamber 7 is reduced as possible so as to shorten a time before the gas reaches equilibrium. Gas belonged to a kind to be measured is sealed in light receiving chambers 11a, 11b and, when the same kind of gas is present in the gas chamber 7, infrared rays having a wavelength range peculiar to said gas emitted from a light source 9 is partially absorbed in the gas chamber 7 and, therefore, infrared rays having said wavelength range incident to a light receiving chamber 11 is reduced. By this phenomenon, pressure difference is generated in the light receiving chambers 11a, 11b by the change of absorbed energy and a gas stream is generated in the conduit connecting the light receiving chambers 11a, 11b. This minute amount of the gas steam is converted to an electric signal by a detector 12 and the gas concn. in the gas chamber can be determined from the signal amount thereof.

Description

Detailed Description of the Invention The present invention detects abnormalities inside the electrical appliance by measuring the type and amount of gas in the oil generated due to some thermal or electrical abnormality in oil-filled insulated electrical equipment such as transformers. This invention relates to an internal abnormality detection device for oil-filled insulated electrical appliances that detects the type and degree of.

Conventionally, as a technology for complete maintenance management of transformers, etc., there are methods using electrical tests such as measuring insulation resistance and dielectric loss tangent, or corona tests, but these methods cannot be measured while the appliance is in operation, and the Operation must be stopped before measurement. On the other hand, a method based on gas-in-oil analysis is widely used as a method for maintaining and managing electrical appliances while they are in operation. This method utilizes the fact that when an abnormality occurs inside a transformer, the insulating oil or thermal decomposition gas of the insulating material dissolves into the pile, and the insulating oil is collected while the oil-filled insulator is in operation. By extracting the gas dissolved in the oil and analyzing it using gas chromatography for hydrogen, C2 (sometimes C4 or lower hydrocarbons, carbon dioxide gas, and carbon oxide), it is possible to determine the type of gas and its proportion. This method diagnoses the type and degree of internal abnormalities.This method has a long track record and is recognized as a highly reliable diagnostic method, so it is mainly used for the management of high-voltage, large-capacity transformers. However, the diagnosis requires approximately 21 oil extractions, as well as gas extraction and analysis steps, which are often outsourced to specialized companies and are difficult to perform frequently, so they are only carried out once a year. It is normal to be diagnosed only one or two times.

Therefore, even if an internal abnormality occurs, it may not be discovered until half a year or nearly a year, depending on the case.

Moreover, statistically speaking, more than 90% of C transformers are operated without any failures, so it can be said that it is wasteful to conduct gas analysis, which requires a considerable amount of money, every time.

On the other hand, as a method of frequently or constantly measuring gas in oil, there is a method that measures the gas that permeates through a polymer membrane in the insulating oil of a transformer, and determines the gas concentration in oil from the relationship of permeation equilibrium. be. The following four methods have been devised so far to measure the gas that has passed through. That is,
(1) fuel cell type, (2) one using a semiconductor gas sensor (see Japanese Patent Application Laid-Open No. 52-322),
(4) Gas chromatography method. Among these, the former champion measures only hydrogen in the permeated gas, but the latter can measure not only hydrogen but also gases with multiple components. Furthermore, in terms of sample gas consumption, methods (1), (2), and (4) are gas consuming types, but method (3) is gas non-consuming. In the case of a gas-consuming type, especially in the case of a total-volume consuming type, the time required to reach permeation equilibrium between one measurement and the next measurement depends on the type and thickness of the polymer membrane. It takes 100 hours. On the other hand, in the case of a non-gas consumption type, there are no special restrictions on the measurement interval. The above method (3) is a gas non-consuming type, but it measures hydrogen and has the disadvantage that it cannot measure other hydrocarbon gases, co, co2, etc. In many cases of internal abnormalities in transformers, hydrogen is generated, but it is not possible to detect all internal abnormalities by analyzing hydrogen alone, and analysis of other gases such as CH4, C2H4, C0, 002, etc. may be detected. In this way, by analyzing not only hydrogen but also other gases, the detection rate of internal abnormalities can be improved, and the type and degree of internal abnormalities can also be estimated from the proportions of each component gas. Therefore, detection of gases other than hydrogen is a very effective method for diagnosing internal abnormalities in transformers, but conventionally there has been no method of detecting gases other than hydrogen that does not consume gas.

This invention eliminates the above-mentioned drawbacks, and is capable of measuring a desired type of gas without consuming the gas that has passed through the permeable membrane from oil, and furthermore, is capable of measuring multiple types of gas simultaneously or by switching between them. It is all about providing.

One embodiment of the present invention will be described with reference to FIG.

The gas-in-oil measuring device of the present invention is attached to a 7-lunge 3 at the end of a pulp 2 attached to a transformer 1. In the middle of the conduit between pulp 2 and 7 lunges 30.

A cock 4 is attached as shown in the figure.

On the outside of the flange 3 are two perforated reinforcing plates 5a.

A permeable membrane 6 sandwiched between the membranes 5b is attached.

Further, a gas chamber 7 for collecting gas passing through the permeable membrane 6 is attached to the outer perforated reinforcing plate 5b. An infrared transmitting window 8 a + is provided on the opposite wall of the gas chamber 7.
8b is installed. An infrared gas detector is provided outside the infrared transmitting windows 8a, 8b. The infrared gas detector includes an infrared light source 9, a chopper 0.2 light receiving chambers 11a and llb, and a detector (micro flow sensor) 12 provided in the middle of a conduit connecting the two light receiving chambers.
It consists of.

The two light receiving chambers 11a and llb are provided with infrared transmitting windows 13a and 13b at the positions shown in the figure, respectively. The light emitted from the infrared light source 9 first
After passing through the gas chamber 70, the light passes through the two transmission windows 8aT8b and enters the light receiving chamber 118.11b. A measuring gas is sealed in the light receiving portions 11a and 11b. In addition, two pipes are connected to the gas chamber 7, and cocks 14a and 14b are installed.
A cover 15 is attached to the outside of the device.

The functions of each part will be described below.

The pulp 2 attached to the transformer l shuts off the insulating oil in the transformer l from the outside air when this device is not connected to the
After this device is attached to the flange 3, it has the function of bringing the insulating oil in the transformer 1 into contact with the permeable membrane 6 through the perforated reinforcing plate 4a. Since it is desired that there is always no difference in the type and amount of dissolved gas between the insulating oil in the portion that contacts the permeable membrane 6 and the insulating oil in the transformer body, it is desirable that the diameter of the pulp 2 be as large as possible. For example, a butterfly valve or ball pulp with a large diameter is suitable. The cock 4 is used to discharge the air that was present between the pulp 2 and the permeable membrane 6 when the pulp 2 is opened to bring the insulating oil in the transformer into contact with the permeable membrane 6 after this device is attached to the flange 3. used for. Therefore, the preferred location for adding the pipe to be attached to the cock 4 is the upper part of the conduit connecting the pulp 2 and the 7-lunge 3, as shown in FIG.

The perforated reinforcing plates 5a and 5b sandwich the permeable membrane 6 between them, and protect the permeable membrane from the hydraulic pressure of the insulating oil.
Any material may be used as long as it does not prevent the dissolved gas in the oil from passing through the permeable membrane 6 and accumulating in the gas chamber 7. Although it depends on the material and thickness of the permeable membrane 6, it is preferable that the holes made in the reinforcing plate be as small and as large as possible. Of course, it is necessary that the structure and material are sufficiently airtight with the outside. Therefore, it is not necessarily necessary to make a hole near the center where it contacts the permeable membrane.
Even if you use , the purpose is achieved.

The permeable membrane 6 may be one that does not allow the insulating oil to pass through and only allows the gas dissolved in the oil to pass through, but since it comes into contact with the insulating oil whose temperature has risen to a certain degree, it may deteriorate or deteriorate due to the insulating oil during the period of use. Preferably something that does not deteriorate. Membranes suitable for this purpose include fluoroethylene (PTFE) and fluoroethylenepropylene (FEP).
and polymer membranes such as polyimide.

Next, since the gas chamber 7 is a part that accumulates gas permeating from the oil, it must be completely airtight except for the opening facing the permeable membrane. Furthermore, since it takes a certain amount of time for the dissolved gas in the oil to permeate into the gas chamber through the permeable membrane and reach equilibrium, the opening area of the gas chamber 7 should be made large and the volume of the gas chamber should be kept as small as possible. It is desirable to configure the structure (by reducing the thickness) to shorten the time for the gas to reach equilibrium. For this purpose, an infrared light source 9, a chopper 10. Light receiving chamber 11a,
It is also desirable that 11b be as small as possible.

The light receiving chamber 11a and Ilb K are filled with a gas to be measured, and when the same type of gas is present in the gas chamber 7, infrared light with a wavelength specific to the gas is partially absorbed in the gas chamber 7. Therefore, the amount of infrared light of the wavelength that enters the light receiving chamber is reduced. Due to this, the light receiving chambers 11a and ll
b K creates a pressure difference due to the change in absorbed energy, and l
A gas flow occurs in the conduit connecting la and 11b. A detector (microflow sensor) 12 converts this small amount of gas flow into an electrical signal, and the concentration of the gas in the gas chamber can be determined from the amount of the signal. The gas filled in the light receiving chamber is CO, which has absorption at specific infrared wavelengths.

Gases such as CO2 and CH4 can be used.

Although FIG. 1 shows the case of measuring one type of gas, it is possible to measure multiple types of gas by using any of the five-order methods.

(1) An infrared light source and a light receiving chamber are provided in parallel for one gas chamber.

(2) A prism is placed just in front of the light-receiving chamber, and the infrared rays are branched to provide parallel light-receiving chambers.

(3) An infrared transmitting window is also provided at the final image plane of the light receiving chamber, and a light receiving chamber is provided in series behind it.

(4) Combining any two or three of the above (1), (2) and (3).

Another embodiment of the invention is shown in FIG. In this figure, the gas chamber 7 is not directly connected to the perforated reinforcing plate 5b, but is connected via a pipe 16, a cock 17, and a joint 18. In this case pipe 16, cock 17
The joint 18 is made of a material that can maintain sufficient airtightness so that the gas that has passed through the permeable membrane does not leak to the outside.
It is desirable to have the minimum size necessary to allow the permeate gas to reach equilibrium in the shortest possible time.

It is also possible to use flexible pipes as long as they meet these requirements. Similarly to FIG. 1, FIG. 2 also shows a single gas component measurement device, but as described in the previous implementation I+o, (1) to (4)
) There is no difference in that the film number component can be measured using the method. Furthermore, in the example of Fig. 3, the cock 1 is
The pipe 16 leading to the infrared 1
It is also possible to measure gases of multiple components by providing a type gas analyzer.

As shown in Figure 2, the gas permeation part and gas detection part can be removed, making maintenance and inspection easier, and the detection part can be easily replaced and measured when measuring a different type of gas. be able to.

According to this invention, since the gas that has permeated through the polymer permeable membrane is analyzed using an infrared gas analyzer, CO, CO2, and
Gases such as CH4 can be measured. For example, among internal abnormalities in a transformer, overheating of metal parts mainly produces C)Ll, and overheating of insulating paper produces CO2.
It is known that the amount of gas and CO2 increases, and it is possible to accurately diagnose the type and degree of internal abnormality from the amount and change tendency of these gas components.

Furthermore, since infrared absorption is used as the analysis method, sample gas is not consumed at all. Therefore, measurements can be made at arbitrary measurement intervals, and changes in the gas concentration within the gas chamber can be tracked. Furthermore, since no gas is consumed, it is also possible to install not only one gas chamber but two or three gas chambers and measure two or three types of gas in parallel. Increasing the volume or number of gas chambers requires more time for the gas in the oil and the gas in the gas chamber to reach equilibrium, so gas-consuming detectors If the time between fire measurements has to be longer, but no gas is consumed, even though the volume of the gas chamber increases and the time to reach equilibrium becomes somewhat longer.

There is no problem in measurement.

Although the present invention has been mainly described with respect to the analysis of gas in insulating oil in a transformer, it can be applied not only to transformers but also to other oil-filled insulated electrical appliances, such as oil-filled circuit breakers, oil-filled capacitors, and oil-filled cables.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment. 2: Bulb, 5a, 5b: Perforated reinforcing plate, 6: Transmissive membrane, 7: Gas chamber, 8a, 8b: Infrared transmitting window, 9: Infrared light source, 11a, 11b "Light receiving chamber,
12: Detector (micro flow sensor).

Claims (1)

[Scope of Claims] 1) A permeable device that is installed so as to be in direct contact with the insulating oil filled in the container that houses the oil-filled insulated electrical appliance, and that only allows gas dissolved in the insulating oil to pass through without passing the insulating oil. a membrane, and an inlet window and an outlet window defined in communication with a side of the permeable membrane opposite to the insulating oil side and transparent to infrared light to collect gas passing through the permeable membrane. a gas chamber sealed so as to maintain its partial pressure in equilibrium with the partial pressure of the gas in insulating oil; and an infrared light source that enters infrared light into the gas chamber through the artificial window;
A gas-in-oil measuring device 2 for an oil-filled insulated electrical appliance characterized by comprising an infrared detector that receives infrared light transmitted through the gas in the gas chamber through the exit window, Claim 1
3) In the measuring device according to claim 1, the gas chamber is fixedly defined adjacent to the permeable membrane. a gas chamber is fixedly defined adjacent to the permeable membrane;
Set aside according to the type of gas that the infrared detector should measure. 4) In the measuring device according to claim 1, the gas chamber includes a gas collection chamber fixedly provided adjacent to the permeable membrane, and a gas collection chamber removably attached so as to communicate with the gas collection chamber. It consists of an infrared light transmission chamber equipped with an entrance window and an exit window, and a cock that temporarily closes the gas collection chamber when the infrared light transmission chamber is attached or removed, and the infrared light transmission chamber and the infrared detector are connected to each other. 1. A gas-in-oil measurement device for an oil-filled insulated electrical appliance, characterized in that the device is configured to be replaceable depending on the type of gas to be measured. 5) The measuring device according to claim 1, characterized in that the permeable membrane is a thin film made of a polymeric material, and is sandwiched between porous reinforcing plates from the insulating oil side and the gas chamber side, respectively. Gas-in-oil measuring device for oil-filled insulated electrical appliances. 6) % Allowance The measuring device according to claim 1 is characterized in that a predetermined gas absorbing infrared light IF is prefilled in the gas chamber at a predetermined pressure so as to resist the pressure of the insulating oil. Gas-in-oil measuring device for oil-filled insulated electrical appliances.