JP2020159829A - Oil overheat test device - Google Patents

Abstract

To provide an oil overheat test device capable of reproducing an overheated state of about 1000°C, eliminating the influence on the way temperature of an insulating oil rises in order to reach the overheated state of a predetermined temperature in a few seconds, and further increasing the degree of freedom regarding a material, a size, a shape, and the like of a heating element.SOLUTION: A test device includes: a sample container 10 inside which oil is stored; an induction heating coil 20 which is wound around the sample container 10 in the outside of the sample container 10; a matching device which supplies electric power to the induction heating coil 20; a heating element 25 which is housed in the inside of the sample container 10 and arranged in a central part of the induction heating coil 20; and a measurement part which measures the temperature of the heating element 25. By supplying electric power to the induction heating coil 20, the matching device makes the heating element 25 generate heat and brings oil T in the sample container 10 into an overheated state.SELECTED DRAWING: Figure 3

Description

The present invention relates to an oil superheat test apparatus for performing an oil superheat test.

Conventionally, in transformers that use insulating oil for insulation and cooling, internal abnormality diagnosis is performed by oil gas analysis for maintenance management. When an overheating abnormality, which is one of the internal abnormalities of a transformer, occurs, it is necessary to estimate the overheating part and the temperature (overheating temperature) and judge the progress of the abnormality.

As one of the maintenance management of mineral oil transformers, internal abnormality diagnosis by gas analysis in oil is generally performed. This is a technique for diagnosing the presence or absence of internal abnormalities, the location of abnormalities, the type of abnormality (discharge, overheating, etc.) and scale from the concentration and generation pattern of gas components in oil. On the other hand, there are no official criteria in Japan for transformers containing new insulating oils such as natural esters and plant-derived esters. Therefore, local superheaters are used to simulate and test possible local superheats inside the transformer in order to gain insights to establish diagnostic techniques.

As a method of diagnosing an overheat abnormality from the outside in a transformer using insulating oil, a method of analyzing a gas component generated from the insulating oil and diagnosing the abnormality is known (see, for example, Patent Document 1). Patent Document 1 describes a technique of performing a superheat test of insulating oil with a superheat test device, collecting the generated gas, and analyzing the components.

In Patent Document 1, an electrode conductor penetrating the side wall of the sample container is provided, electrodes are attached to the electrode conductors facing each other on the center side of the sample container, and a metal heating conductor is horizontally supported between these electrodes. The heating test equipment that has been used is described. In this device, the insulating oil in the sample container is heated by energizing the electrode conductor and the heating conductor via the electrode.

Japanese Unexamined Patent Publication No. 2017-215320

In the above-mentioned conventional technique, since energization heating is used as a method for heating the insulating oil, the maximum temperature of the heating conductor is as low as about 700 ° C., and the test apparatus can reproduce a high temperature (about 1000 ° C.) superheated state. It was difficult. Further, in energization heating, it takes about several minutes to reach a superheated state at a predetermined temperature, so gas is generated even while the temperature of the insulating oil is rising, and the influence of the heating process can be eliminated. It was difficult. In addition, there are many restrictions on the material, size, shape, etc. that can be used as the heating conductor, and the degree of freedom in testing is low.

The present invention has been made in view of the above-mentioned problems, and can reproduce a superheated state at a high temperature of about 1000 ° C., and in order to reach a superheated state at a predetermined temperature in about a few seconds, the temperature of the insulating oil is being raised. It is an object of the present invention to provide an oil superheat test apparatus capable of eliminating the influence of the above and further increasing the degree of freedom regarding the material, size, shape, etc. of the heating element.

The present invention constitutes the following oil overheating test apparatus in order to solve the above-mentioned problems.

(1) A sample container in which oil is stored, an induction heating coil wound around the sample container outside the sample container, a matching element for supplying power to the induction heating coil, and the sample container. An oil overheating test device including a heating element housed inside and arranged in the central portion of the induction heating coil and a measuring unit for measuring the temperature of the heating element, wherein the matching device is the induction heating. An oil overheating test device that heats the heating element by supplying power to the coil and puts the oil in the sample container into an overheated state.

(2) The method according to (1), wherein a reduced diameter portion is formed in the lower portion of the sample container and the diameter is reduced toward the lower side, and the induction heating coil is wound around the reduced diameter portion. Oil overheating test equipment.

(3) The oil superheat test apparatus according to (1) or (2), wherein a gas sampling unit and / or a gas sampling mechanism for collecting gas generated from oil is connected to the sample container.

(4) The oil superheat test apparatus according to any one of (1) to (3), wherein an oil sampling unit for collecting oil after overheating is connected to the sample container.

(5) The oil overheating test apparatus according to any one of (1) to (4), wherein a cooling pipe is housed in the sample container, and cooling water for cooling the oil is circulated in the cooling pipe.

According to the oil superheat test apparatus according to the present invention, it is possible to reproduce a superheated state of about 1000 ° C., and eliminate the influence of the temperature of the insulating oil rising in order to reach the superheated state of a predetermined temperature in about a few seconds. Furthermore, the degree of freedom regarding the material, size, shape, etc. of the heating element can be increased.

The front view which shows the whole structure of the oil superheat test apparatus which concerns on one Embodiment. The perspective view which shows the whole structure of the oil superheat test apparatus which concerns on one Embodiment. Partial cutout front view showing the sample container. Top view showing a sample container. FIG. 4 is a sectional view taken along line XX in FIG.

Hereinafter, the oil superheat test apparatus (hereinafter, simply referred to as “test apparatus”) 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5. The test device 1 is a device for simulating and testing the local overheating that may occur inside the transformer. Specifically, as shown in FIG. 3, the oil T is heated in a state where the insulating oil T is stored in the sample container 10, and the insulating oil or the insulating oil is used to analyze the components of the gas generated at that time. It is configured to take gas.

In the present embodiment, as the oil T, any of mineral oil, natural ester, and plant-derived ester was used. In this specification, the state in which heat is simply applied to the oil T is described as "heating", and the state in which heat generated by an internal abnormality of the transformer is applied to the oil T to generate gas is described as "overheating". To do.

As shown in FIG. 1, the test apparatus 1 includes a gantry 2, a sample container 10, an induction heating coil 20, a matching device 30, a measuring unit 40, a cooling unit 50, a gas collecting bag 60, and the like. Hereinafter, each component will be described in order.

The gantry 2 is a pedestal for supporting the sample container 10, the induction heating coil 20, the matching device 30, and the like. Two elevating platforms 3 and 3 are provided on the upper surface of the gantry 2 in an overlapping manner. One left side support member 4L and two right side support members 4R and 4R are erected on the upper surface of the upper elevating table 3 (see FIGS. 1 and 2). Piping and the like, which will be described later, are fixed to the left side support member 4L and the right side support member 4R / 4R.

A container support plate 6 extending to the right side is fixed to the upper part of the right side support members 4R and 4R so as to be parallel to the floor surface. A sample container 10 is provided on the container support plate 6. An induction heating coil 20 that is wound around the sample container 10 at a slight distance from the sample container 10 is arranged on the outside of the lower portion of the sample container 10. As shown in FIG. 2, the test apparatus 1 according to the present embodiment is provided with a resin protective cover member 5 that surrounds the sample container 10.

A matching device 30 for supplying electric power to the induction heating coil 20 is arranged on the upper surface of the upper elevating table 3. A temperature controller 31 housed in the gantry 2 and an induction heating power supply 32 having a capacity of 10 kW are connected to the matching device 30. The user of the test apparatus 1 adjusts the electric power supplied to the induction heating coil 20 by the matching unit 30 by operating the temperature controller 31.

As shown in FIG. 1, the measuring unit 40 is connected to the sample container 10. The measuring unit 40 is composed of a measuring device 41 composed of a general computer or the like, a first thermocouple 42, and a second thermocouple 43. In FIG. 2, the measuring device 41 is not shown.

Further, as shown in FIG. 1, a cooling unit 50, which is a cooling device (chiller) for circulating cooling water, is connected to the sample container 10. The cooling unit 50 is connected to the sample container 10 via the first cooling path 51, the first valve 52 fixed to the left side support member 4L, and the second cooling path 53, which are the outward paths of the cooling water. Further, the cooling unit 50 is connected to the sample container 10 via a third cooling path 54, a second valve 55 fixed to the left support member 4L, and a fourth cooling path 56, which are return paths for the cooling water. .. In FIG. 2, the first to fourth cooling paths 51, 53, 54, and 56 are not shown.

Further, as shown in FIG. 1, a gas collection bag 60, which is a gas collection unit, is connected to the sample container 10. The gas collection bag 60 is connected to the sample container 10 via the first gas collection path 61, the flow meter 62, the gas valve 63 fixed to the left support member 4L, and the second gas collection path 64. The flow meter 62 measures the flow rate of the gas flowing inside and the integration thereof, and the non-contact type is adopted in the present embodiment. The accumulated data can be taken out from the flow meter 62. In FIG. 2, the gas collection bag 60 and the second gas collection path 64 are not shown.

As shown in FIGS. 3 and 5, the sample container 10 is composed of a hollow tubular main body portion 10a and a lid portion 10b that closes the upper opening of the main body portion 10a. The lid portion 10b is removable from the main body portion 10a. The contact surface between the main body portion 10a and the lid portion 10b is sealed with a sealing member so that the generated gas or the like does not leak. As shown in FIGS. 3 and 4, the lid portion 10b functions as a connector for connecting various members to the sample container 10.

The main body 10a is made of a material that is not affected by the induction heating by the induction heating coil 20 and is not affected by the high temperature. In the present embodiment, the main body 10a is made of glass. The main body 10a is formed so that the internal volume excluding the instruments housed inside is about 1000 to 2000 mL. At the lower part of the main body portion 10a of the sample container 10, a reduced diameter portion 10c whose diameter is reduced toward the lower side is formed. As shown in FIG. 3, the induction heating coil 20 is wound around the reduced diameter portion 10c.

An oil sampling portion 16 is formed in the lower portion of the reduced diameter portion 10c. The oil sampling unit 16 includes a discharge member 16a that is inserted into the lower opening of the main body portion 10a. A discharge path 16b is formed inside the discharge member 16a as shown in FIG. The oil T after the test can be collected from the sample container 10 through the oil collecting unit 16. The discharge member 16a in the oil sampling unit 16 also functions as an introduction port when bubbling with nitrogen gas before heating the oil T.

As shown in FIGS. 3 to 5, a cylindrical shaft holder 21 is attached to the central portion of the lower surface (inner side surface of the sample container 10) of the lid portion 10b, and the upper end portion of the shaft 22 is assembled to the shaft holder 21. It is attached. The upper end of the rod 24 is connected to the lower end of the shaft 22 via a coupling 23. A heating element 25 that generates heat by induction heating generated by supplying electric power to the induction heating coil 20 is attached to the lower end of the rod 24. The heating element 25 is arranged so as to be located at the central portion of the wound induction heating coil 20. A groove 25a for inserting the thermal contact of the first thermocouple 42 is formed in the heating element 25.

The material of the heating element 25 may be any material that generates heat by induction heating, and iron, SUS304, tungsten, or the like is adopted. The heating element 25 is formed so that the length, width, and height fit within the dimensions of 3 mm to 10 mm in consideration of the inner diameter of the induction heating coil 20 and the heat generation efficiency, and the shape thereof is a sphere, a cube, a cylinder, a cylinder, or the like. , It is possible to adopt various shapes. In the test apparatus 1 according to the present embodiment, the heating element can be heated to 1000 ° C. or higher by supplying electric power to the induction heating coil 20.

As shown in FIGS. 3 and 4, the lid portion 10b of the sample container 10 is provided with the first joint 12 and the second joint 13. By connecting the first joint 12 to the second cooling path 53, the first joint 12 serves as an inlet for cooling water sent from the cooling unit 50 to the sample container 10. The second joint 13 is connected to the third cooling path 54 to serve as an outlet for cooling water from the sample container 10. The first joint 12 and the second cooling path 53, and the second joint 13 and the third cooling path 54 are configured to be easily removable at the time of cleaning or the like.

As shown in FIG. 3, a cooling pipe 14 that communicates the first joint 12 and the second joint 13 is housed inside the main body portion 10a of the sample container 10. The cooling pipe 14 is arranged inside the main body 10a in a spiral shape that winds around the shaft 22, and the cooling water sent from the cooling unit 50 is circulated inside the cooling pipe 14. The cooling pipe 14 is made of a stable metal material having low reactivity with the induction heating coil 20, and stainless steel is used in the present embodiment. Further, the cooling pipe 14 is arranged above the induction heating coil 20 so as not to be affected by the induction heating coil 20.

In this embodiment, the cooling pipe 14 is arranged so as to be located above the heating element 25. As a result, the oil T can be efficiently cooled when the heated oil T is convected due to the heating element 25 generating heat.

Further, the lid portion 10b is provided with a gas collecting connection portion 15 as a gas collecting portion for collecting the gas generated from the superheated oil T. The tip of the gas collection connection portion 15 is inserted into the sample container 10 as a gas collection port 15a. By connecting the gas collection connection portion 15 to the first gas collection path 61, the gas flowing out from the gas collection port 15a is collected in the gas collection bag 60.

Further, the lid portion 10b is provided with a stirring member 17. A stirring portion 17a located inside the sample container 10 is provided at the lower end portion of the stirring member 17. With the stirring unit 17a inserted in the oil T, the user of the test apparatus 1 can manually rotate the stirring member 17 to stir the oil T. It is also possible to have a configuration in which the stirring member 17 is automatically rotated.

Further, the lid portion 10b is provided with a tubular gas sampling port 18 as a gas sampling mechanism for collecting gas generated from the superheated oil T. The lower end of the gas sampling port 18 is inserted inside the sample container 10. In the test device 1, the gas generated inside the sample container 10 can be collected by connecting a syringe or the like to the upper end of the gas collection port 18.

Further, the lid portion 10b is provided with a first thermocouple mounting portion 19a and a second thermocouple mounting portion 19b. The first thermocouple 42 is attached to the first thermocouple attachment portion 19a. The first thermocouple 42 measures the temperature of the heating element 25, which becomes 1000 ° C. or higher, by attaching the thermal contact to the heating element 25. The second thermocouple 43 measures the temperature of the oil T, which rises to about 20 ° C. to 100 ° C. by inserting the thermal contact into the oil T.

As described above, in the test apparatus 1, the matching device 30 supplies electric power to the induction heating coil 20 to generate heat of the heating element 25, so that the oil T stored inside the sample container 10 is overheated. It is composed of. As described above, the test apparatus 1 employs induction heating to heat the oil T. This makes it possible to reproduce the superheated state by setting the temperature of the heating element 25 to about 1000 ° C.

Further, by adopting induction heating in the test apparatus 1, the heating element 25 can reach a superheated state of a predetermined temperature in about a few seconds. Therefore, it is possible to eliminate the influence of the oil T while the temperature is rising. In other words, the temperature of the heating element 25 in the oil T can be easily set to a predetermined temperature, and the generation of unnecessary gas due to the variation in temperature can be prevented, so that the test accuracy by the test apparatus 1 can be improved. is there. Further, the heating element 25 may have a shape that can be supported by the rod 24, and since it is not necessary to connect a wire or the like to the heating element 25, the degree of freedom regarding the material, size, shape, etc. of the heating element 25 is increased. be able to

Further, in the test apparatus 1, a reduced diameter portion 10c whose diameter is reduced toward the lower side is formed in the lower portion of the sample container 10, and the induction heating coil 20 is wound around the reduced diameter portion 10c. As a result, the distance between the induction heating coil 20 and the heating element 25 can be shortened while securing the capacity of the sample container 10. That is, since the magnetic flux density generated around the heating element 25 can be increased, the heating efficiency of the heating element 25 can be increased.

Further, in the test apparatus 1 according to the present embodiment, the sample container 10 is provided with a gas collection connection unit 15 as a gas collection unit for collecting gas generated from the superheated oil T. As a result, the gas generated by the test apparatus 1 can be collected in the gas collection bag 60. Further, the sample container 10 is provided with a tubular gas sampling port 18 as a gas sampling mechanism for collecting gas generated from the superheated oil T. As a result, the gas inside the sample container 10 can be collected by connecting a syringe or the like to the upper end of the gas collection port 18.

Further, in the test apparatus 1 according to the present embodiment, the oil sampling unit 16 is connected to the sample container 10. As a result, the oil T after the test can be collected from the sample container 10 via the oil collecting unit 16.

Further, in the test apparatus 1 according to the present embodiment, the sample container 10 accommodates the cooling pipe 14, and the cooling pipe 14 is circulated with cooling water for cooling the oil T. As a result, the oil T heated inside the sample container 10 can be cooled. Further, in the present embodiment, the cooling pipe 14 is arranged so as to be located above the heating element 25. As a result, the oil T can be efficiently cooled when the heated oil T is convected due to the heating element 25 generating heat.

1 Test equipment (oil overheat test equipment) 2 Stand
3 Lifting platform 4L Left support member
4R Right side support member 5 Protective cover member
6 Container support plate 10 Sample container
10a Main body 10b Lid
10c reduced diameter part 12 first joint
13 Second fitting 14 Cooling pipe
15 Gas collection connection (gas collection unit)
15a Gas collection port 16 Oil sampling unit
16a Discharge member 16b Discharge route
17 Stirring member 17a Stirring part
18 Gas sampling port (gas sampling mechanism)
19a 1st thermocouple mounting part 19b 2nd thermocouple mounting part
20 Induction heating coil 21 Shaft holder
22 Shaft 23 Coupling
24 rod 25 heating element
25a Groove 30 Matcher
31 Temperature controller 32 Induction heating power supply
40 Measuring unit 41 Measuring device
42 1st thermocouple 43 2nd thermocouple
50 Cooling unit 51 First cooling path
52 1st valve 53 2nd cooling path
54 Third cooling path 55 Second valve
56 Fourth cooling path 60 Gas collection bag (gas collection unit)
61 First gas collection path 62 Flow meter
63 Gas valve 64 Second gas collection path
T oil

Claims (5)

A sample container in which oil is stored, an induction heating coil wound around the sample container outside the sample container, a matching element for supplying power to the induction heating coil, and a matching element stored inside the sample container. An oil overheating test apparatus comprising a heating element arranged in the central portion of the induction heating coil and a measuring unit for measuring the temperature of the heating element.
An oil superheat test apparatus in which the matching element supplies electric power to the induction heating coil to heat the heating element and overheat the oil in the sample container. A reduced diameter portion is formed in the lower part of the sample container, which is reduced in diameter toward the bottom.
The oil superheat test apparatus according to claim 1, wherein the induction heating coil is wound around the reduced diameter portion. The oil superheat test apparatus according to claim 1 or 2, wherein a gas sampling unit and / or a gas sampling mechanism for collecting gas generated from oil is connected to the sample container. The oil superheat test apparatus according to any one of claims 1 to 3, wherein an oil sampling unit for collecting oil after overheating is connected to the sample container. The oil overheating test apparatus according to any one of claims 1 to 4, wherein a cooling pipe is housed in the sample container, and cooling water for cooling the oil is circulated in the cooling pipe.

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