JPH01203982A - Detecting device for combustible gas in oil - Google Patents

Abstract

PURPOSE:To extract a gas dissolved in insulating oil without contacting outside air and to evade an influence upon equipment by providing an extraction cylinder which extracts the dissolved gas, an extracted gas reservoir chamber, a vacuum pump, a gas detection chamber, etc. CONSTITUTION:The extracted gas passes through a solenoid valve 15 from the extraction cylinder and then passes through a oil detector 16 and is guided to the gas reservoir chamber 20. A gas detector 24 which measures the amount to combustible gas in the extracted gas sent in through a solenoid valve 27 and piping which connects them are provided behind the gas reservoir chamber 20. Further, air piping which sends the extracted gas collected in the gas reservoir chamber 20 in the detection chamber 24 is provided in the middle of piping which links an oil detector 16 with the gas reservoir chamber 20. Further, a path which links a vacuum pump 17 for evacuating the gas reservoir chamber 20 through solenoid values 19 and 18 is provided in the middle of piping which links the gas reservoir chamber 20 and a solenoid valve 27 with each other. This constitution extracts the dissolved gas in the insulating oil without contacting the outside air and prevents the oxygen of the outside air from being dissolved in the insulating oil to evade the adverse influence upon the equipment.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention separates flammable gas dissolved in the insulating oil of oil-filled electrical equipment, such as oil-filled transformers, and separates the separated flammable gas. This invention relates to a device that measures the amount of oil and detects abnormalities in oil-filled equipment at an early stage.

[Conventional technology]

When a thermal or electrical abnormality occurs inside an oil-immersed electrical device, such as an oil-immersed transformer, the insulating oil and materials around it decompose, producing gas. These gases dissolve in the insulating oil and the gas concentration in the oil increases, so the gas dissolved in the oil (hereinafter referred to as gas in oil) is extracted and analyzed, and based on the analysis results, the inside of the transformer can be detected. A method for diagnosing abnormal conditions is already well known, and it is widely used both in Japan and abroad because it allows early detection of abnormal conditions.

The commonly used method for analyzing gas in oil is to collect insulating oil from the target transformer, then extract the gas in oil using Torricelli vacuum using mercury or vacuum with a Depra bomb, and then collect the extracted gas using gas chromatography. It is analyzed using a tograph. However, while this method is easy to implement, it is performed manually or semi-automatically, so it requires human intervention throughout the entire process from the start of the analysis to the end, and the operations are complex, requiring a high degree of skill to perform highly accurate analysis. We need qualified engineers. And it took an hour of hard work.

Requires expenses. For this reason, automatic gas analyzers that can be installed on-site and that automate these operations have also been developed. However, the device is expensive and requires a lot of effort to maintain.

On the other hand, recently, as an alternative to gas extraction devices that are complicated to operate, a method has been devised that uses a gas permeable material that allows only gas to pass through, but not liquid. This method involves attaching a polymer membrane to a part of the transformer, such as an oil drain port, to separate the oil from the gas detection chamber, and then transmitting the gas that has passed through the membrane into the detection chamber using an electrolyte, etc., or a catalytic combustion method. It uses a semiconductor gas detection element to detect abnormalities inside the transformer. Although this method has a simple and inexpensive device, it has the disadvantage that the gas concentration within the detection chamber does not reach equilibrium easily due to the relatively slow gas permeation rate, which delays the detection of abnormalities. Another disadvantage is that oxygen in the detection chamber penetrates through the membrane and dissolves into the insulating oil inside the transformer, adversely affecting the transformer.

[Problem to be solved by the invention]

In view of the shortcomings and problems of the prior art as described above, an object of the present invention is to provide a device for detecting flammable gas in oil, in which the operation for extracting gas in oil is simple, and the gas extraction procedure is performed using insulating oil in the equipment. It is constructed so that it does not take time to extract gas so that it does not have any adverse effects on the equipment, such as oxygen dissolving into the equipment, and does not delay the discovery of equipment abnormalities. Sometimes, there is no means to completely eliminate gas remaining in the system of the device, leaving problems in reliable evaluation of detection accuracy next time.
It is an object of the present invention to inexpensively construct an apparatus that leaves no problem in evaluating detection accuracy other than the detection accuracy of a gas detector itself including a gas detection element.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, a combustible gas in oil detection device collects insulating oil in oil-filled electrical equipment by moving a piston equipped with a bellows back and forth, and detects the dissolution in the insulating oil. An extraction cylinder that extracts gas, a gas storage chamber that is piped to the extraction cylinder and stores the extracted gas, a vacuum pump that evacuates the gas storage chamber, and sends out air that sends the extracted gas in the gas storage chamber to the gas detection chamber. air pump,
The gas detection chamber is equipped with a gas detection element for detecting combustible gas, and the extracted gas is circulated through the gas detection chamber, the air pump, and the gas reservoir chamber in order to detect the combustible gas in the extracted gas. shall be measured.

[Effect]

By configuring the gas detection device in this way, gas in oil can be extracted by fixing one end of the bellows coaxially to one end of the piston, and fixing the other end of the bellows to the cylinder to control the forward and backward movement of the piston. By repeating this process, it becomes possible to extract new insulating oil inside the equipment into the space between the bellows and cylinder while removing the old insulating oil that remained in the insulating oil extraction system during the previous gas detection. With,
The gas dissolved in this extracted new insulating oil is moved back and forth again to move the piston back and forth, and the oil extracted between the bellows and the cylinder is passed through the pores penetrating the piston back and forth, and the pressure behind the piston is reduced. The dissolved gas in the insulating oil can be extracted by violently squirting it into a space that has
Since the parts surrounding this extracted gas are thick metal parts such as pistons and cylinders, oxygen in the air from outside will not seep into the oil through the cylinder wall or mix into the extracted gas. Before the gas extracted behind the piston is sent into the gas reservoir chamber by the forward and backward movement of the piston, the vacuum pump constituting the device of the present invention is designed to prevent the gas remaining in the gas reservoir chamber at the time of previous gas detection from being removed. Since the gas is completely removed, only completely new gas is stored in the gas reservoir chamber. Also,
The standard mixed gas that is introduced into this gas storage chamber and sent into the gas detection chamber and used to calibrate the gas detection elements installed in this chamber is also completely removed after calibration, and this calibration gas is also a dissolved gas. Moreover, in the device configuration according to the present invention, before the extracted gas is sent into the gas detection chamber, fresh air from the outside is introduced into the gas detection chamber by the air pump, and this air is Since it is easily possible to configure the piping system on the gas detection chamber outlet side so that the gas is discharged from the gas detection chamber to the outside of the system, the gas detection chamber can be flushed with fresh air while the air pump is running. Therefore, the gas detection element can begin detection operation in a new and stable state without being affected by the previous extraction gas or calibration gas.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 shows a system diagram for explaining the configuration of the oil-soluble gas detection device according to the present invention and the paths of oil and gas, and will be explained below with reference to each component and function of the device. .

(1) Collection of sample oil into the extraction cylinder A piston 2 is disposed in the extraction cylinder 1 so as to be slidable in the axial direction by a piston rod 3 provided at the center thereof. The upper end surface of a bellows 4, which has an outer diameter slightly smaller than the diameter of the piston, is oil-tightly fixed to the lower surface of the piston 2, and the lower end surface of this bellows is oil-tightly fixed to the bottom surface of the extraction cylinder 1.
A first figurine is formed between the bellows 4 and the brewing cylinder 1 in a hermetically sealed manner. The piston 2 is provided with several pores 6 extending from its outer circumferential surface to its upper surface. 0 between the portion of the outer peripheral surface of the piston 2 above the opening of the pore 6 and the inner wall surface of the extraction cylinder 1.
A ring 5 is arranged, and a second chamber 41 is formed above the O-ring 5 in the inner chamber of the extraction cylinder 1 .

On the other hand, the flow path of the sample oil flowing into and being discharged from the extraction cylinder 1 is between the oil intake port at the bottom of the oil-filled transformer 8 having the insulating oil 7 and the oil return port at the top of the oil-filled transformer 8. Although it is piped, there is a solenoid valve 9° and a reverse valve 13. a path piped so as to communicate with the first chamber opening via the solenoid valve 10;
A solenoid valve 11 connected to a pipe extending upward from the second chamber 41. The reverse valve 14 consists of a path that is piped to an oil return port provided at the top of the oil-immersed transformer 8 via the solenoid valve 12, and a pipe that connects these two paths.

Next, a procedure for collecting the insulating oil 7 in the oil-immersed transformer s into the extraction cylinder 1 using the configuration up to this point will be explained.

The piston 2 stops at the uppermost position in the extraction cylinder 1,
Solenoid valves 9, 10, 11, and 12 are open,
Since oil flows through the check valve 13 only from the oil-immersed transformer 8 side, and oil flows through the reverse valve 14 only from the extraction cylinder l side,
In this state, when the piston 2 is lowered to the lowest position by the piston rod 3, the gz chamber 41 formed between the extraction cylinder 1 and the piston 2 is depressurized, so that the insulating oil 7 is transferred to the solenoid valve 9. It flows into the extraction cylinder 1 through the reverse valve 13 and the solenoid valve 11.

At this time, the oil existing in the first mold cutter is pressurized by the descent of the piston 2 and is pushed out through the solenoid valve 10, but the flow is blocked to the reverse valve 13 and an oil-filled transformation pressure is applied. The insulating oil 7 flowing from the container 8 joins with the solenoid valve 1.
1 and is collected into the second chamber 4].

Next, when the piston rod 3 is operated to raise the piston 2 to its maximum position, some of the oil that had accumulated in the second chamber 41 flows into the first chamber 40 through the pore 6 of the piston 2. , most of them are solenoid valves 11. It passes through the check valve 14 and the solenoid valve 12 and returns to the inside of the oil-immersed transformer 8 from the oil return port at the top of the oil-immersed transformer 8 . At the same time, the first chamber 40 is depressurized and the insulating oil 7 is supplied to the solenoid valve 9. The oil flows here through the check valve 13 and the electromagnetic valve 10, but at this time, some oil is mixed in from the piping connecting the two paths.

By repeating the above operation about six times, the oil collected in the extraction cylinder 1 is replaced with new insulating oil 7. Finally, by stopping the piston 2 at the uppermost position, the oil accumulated in the second chamber 41 in the extraction cylinder 1 is discharged, and a certain amount of the insulating oil 7 is collected into the first household message.

(2) Gas extraction from the collected insulating oil In order to extract the gas in the insulating oil 7 collected in the extraction cylinder 1 and guide it to the flammable gas detection part, a gas reservoir is placed outside the upper part of the extraction cylinder 1. An extraction gas path is provided in communication with. That is, the extracted gas is guided from the extraction cylinder 1 through the solenoid valve 15 and the oil detector 16 to the gas reservoir (9), but after this gas reservoir is loaded, the extracted gas is sent through the solenoid valve n. A separate gas detection chamber for measuring the amount of combustible gas in this gas and piping connecting these are installed.
Further, an air pipe is provided in the middle of the pipe connecting the oil detector 16 and the gas reservoir to send the extracted gas collected in the gas reservoir to the gas detection houses. Also,
In the middle of the piping connecting the gas reservoir chamber (9) and each solenoid valve, a path is provided which connects the solenoid valves 19 and 18 to a vacuum pump 17 for evacuating the inside of the gas reservoir.

Insulating oil 7 collected in extraction cylinder 1 with the previous configuration
The following describes the procedure for extracting gas in oil.

When the piston 2 at the highest limit position is lowered to the lowest position by closing the solenoid valves 10, 11 and 15, the upper second chamber 41 in the extraction cylinder 1 is depressurized and the lower first chamber 41 is lowered.
As the pressure in the chamber 40 increases, the sample oil collected in the first mold cut passes through the pore 6 in the upper part of the piston 2 and is violently injected into the chamber 41 of f42 in the extraction cylinder 1. Since the region is in a vacuum state, the gas dissolved in the insulating oil 7 is separated from the oil. When the piston 2 reaches the lowest position and rises again (when the solenoid valve 15 is opened (
The gas separated and extracted from the insulating oil 7 passes through the oil detector 16 and is led to the gas reservoir type. Leave it in a vacuum state. The piston 2 further rises, and the oil in the second chamber 41 rises, causing the oil detector 1 to rise.
6 or when the piston 2 reaches the uppermost position, the solenoid valve 15 is closed. By repeating the above operation to approximately the same extent, the gas dissolved in the insulating oil 7 is extracted almost entirely and collected in the gas reservoir chamber.

(3) Measuring the amount of combustible gas in the extracted gas Inside the gas detection chamber U, there is a catalytic combustion type gas detection element to measure the amount of flammable gas in the extracted gas, and a temperature compensation device to reduce the influence of temperature. A pair of elements is installed, and when a flammable gas is sent, it burns on the surface of the gas detection element, which increases the temperature of the gas detection element, and the gas detection element and temperature compensation element are assembled as a circuit element. When the balance between the blown and the blown gas is disrupted, a voltage corresponding to the soluble gas ax is output. This gas detection element is not limited to a catalytic combustion type, and may be a semiconductor type gas detection element, an electrolyte electrode, or the like as long as it can detect combustible gas.

On the other hand, the extraction gas flow path, which allows the extraction gas stored in the gas storage chamber to flow into the gas detection units and measures the amount of combustible gas, is connected to the free end outside the system to introduce air from outside the system. An air pump 21 that circulates gas in the system from a solenoid valve 31 used for , from the gas reservoir chamber to the solenoid valve, to the gas detection chamber,
A path connected to the outside of the system via a solenoid valve n, and connect these two paths to the piping between the solenoid valve n and another gas detection chamber via the solenoid valve n, and between the solenoid valve and the flow rate adjustment valve n. A path connecting the piping between the gas detection chamber U and the solenoid valve n and a piping between the air pump 21 and the solenoid valve 31 via the solenoid valve (9), and a path connecting the gas reservoir chamber or From solenoid valve 19
and a path connected to the outside of the system via δ.

Next, a procedure for measuring the amount of combustible gas in extracted gas using the conventional configuration will be described. The solenoid valves 31° and 32 are opened and closed to operate the air pump 4 and remain in the gas detection chamber. This eliminates the combustible gas that flowed in during the previous gas detection and stabilizes the output of the gas detection element placed indoors.

If it is clear that no flammable gas was detected during the previous gas detection, skip this operation and restart the air pump 2.
1. The air between the flow rate regulating pulp n, the solenoid valve n, the gas detection chamber U and the solenoid valve (9) is circulated within the system by opening the solenoid valve (9) and operating the air bomber.
Stabilizes the output of the gas detection element installed inside the gas detection chamber. At this time, the flow rate of air flowing through the system is regulated by a flow rate control valve B. Next, solenoid valves 6 and 1
9 is opened to introduce air into the gas reservoir m, and the gas is mixed with the extracted gas collected in the gas reservoir m, and the inside of the gas reservoir m is brought to atmospheric pressure, after which the solenoid valves 5 and 19 are closed.
Furthermore, at the same time as the solenoid valve and the nail are opened, the solenoid valve n is closed and the air circulating in the system is pumped through the air pump 21 → flow rate adjustment pulp n → solenoid valve is added → gas reservoir chamber I → solenoid valve r → gas detection chamber Circulate in the order of Sae → Solenoid valve addition → Air pump 21. With this air flow, the extracted gas in the gas storage chamber m circulates within the system, and the amount of combustible gas is measured. After the measurement is completed, open all solenoid valves to bring the system to atmospheric pressure.

(4) Calibration of gas detection elements Since each gas detection element has different characteristics and changes over time, it is necessary to calibrate it before starting use and periodically. The configuration and procedure will be explained below.

A calibration gas pipe connected to the pipe between the solenoid valves 18 and 19 is connected to a standard mixed gas (not shown) via a three-way solenoid valve array and a solenoid valve 4.

The other end of the three-way solenoid valve is connected to the outside of the system.

The proofreading process is as follows. The electromagnetic valves 18 and 19 are opened, and the vacuum pump 17 is operated to evacuate the inside of the gas storage chamber m. Thereafter, solenoid valve 18 is closed, solenoid valves 4 and 19 are opened, and the standard mixed gas is introduced into the gas reservoir chamber. At this time, the three-way solenoid valve Z closes the zero-order solenoid valve Z, which is a flow path connecting the solenoid valves 4 and 19, and switches the flow path of the three-way solenoid valve from the solenoid valve 19 to a flow path outside the system to supply the gas. The excess standard gas in the reservoir fi20 is discharged to bring it to atmospheric pressure. After that, the solenoid valve 19 is closed, and at the same time the solenoid valves 1 and 2 are opened, the solenoid valve field is closed and the air circulating in the system is introduced into the gas reservoir chamber I by the air pump 21,
The standard gas in the gas reservoir chamber m is circulated through a flow path passing through the gas detection chamber. Then, the relationship between the output of the gas detection element and the standard mixed gas concentration at this time is measured.

〔Effect of the invention〕

As described above, according to the present invention, gas in oil is extracted using a bellows piston method, and one end surface of the bellows is coaxially fixed to one end surface of the piston, and the other end surface of the bellows is fixed to the cylinder. By repeating the movement of the piston back and forth, the old insulating oil that remained in the insulating oil extraction system during the previous gas detection is removed, and new insulating oil inside the equipment is extracted into the space between the bellows and cylinder. At the same time, by moving the piston back and forth again, the gas dissolved in this extracted new insulating oil is removed between the bellows and the cylinder, and the extracted oil is removed from the pressure behind the piston. Since the gas dissolved in the insulating oil can be extracted by violently ejecting it into the insulating oil, the dissolved gas in the insulating oil can be extracted without coming into contact with the outside air. Oxygen is not dissolved (this prevents negative effects on the equipment.Also,
For the detection of extracted gas, the purpose of gas detection must first be
Essentially, it involves detecting the presence or absence of an internal abnormality in oil-filled electrical equipment, especially power transformers that have a large impact on the operation of the power system, and the cause of an abnormality cannot be investigated until the question of the abnormality arises. Therefore, instead of using an expensive gas chromatograph that can distinguish the type of gas, which is necessary to investigate the cause, we used a much cheaper gas detection element that can only detect the entire view of combustible gas. Therefore, together with the bellows piston type extraction cylinder, it is possible to obtain a gas detection device that is inexpensive, practical, and requires less maintenance effort, without having any adverse effect on equipment. Furthermore, the gas detection device according to the present invention includes a vacuum pump, which remains in the system of the device prior to gas detection. Since the extracted gas from the previous gas detection is completely removed by the vacuum pump and only the gas dissolved in the new oil is detected, the reliability of the detection results is significantly improved. In addition, the gas detection chamber in which the gas detection element for detecting gas is arranged can be cleaned by pumping in new air with an air pump and flushing the gas detection chamber with the gas detection element that detects the gas. It is possible to start detection operation in a new and stable state without the influence of calibration gas or calibration gas. In addition, gas detection is performed using an air pump that circulates the gas storage chamber, gas detection chamber, air bomb, and waste, so the entire amount of extracted gas is detected without leaking out of the system, and the new gas quantification result is Reliability is increased to the ultimate level.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the configuration of a gas detection device and oil and gas paths according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Extraction cylinder, 2... Piston, 4... Bellows, 7... Insulating oil, 8... Oil-immersed transformer (oil-filled electrical equipment), 17... Vacuum pump, ...Gas reservoir chamber, 21...Air pump, Mu...Gas detection chamber.

Claims (1)

[Claims] 1) An extraction cylinder that collects insulating oil in oil-filled electrical equipment and extracts dissolved gas in the insulating oil by the forward and backward movement of a piston equipped with a bellows, and a gas reservoir that is piped to the extraction cylinder and stores the extracted gas. , a vacuum pump that evacuates the gas storage chamber, an air pump that sends air to send the extracted gas in the gas storage chamber to the gas detection chamber, and a gas detection chamber that is equipped with a gas detection element that detects combustible gas. A combustible gas detection device in oil, comprising: measuring the amount of combustible gas in the extracted gas while sequentially circulating the extracted gas through the gas detection chamber, the air pump, and the gas reservoir chamber.