Aging test device and method for transformer sealing element under multi-stress combined action

Abstract

The invention discloses an aging test device for a transformer sealing element under the multi-stress combined action, and the aging test device comprises a test cavity, a heater, a vibrator, an oil conveyor and a sealing element sample fixing structure which is arranged in the test cavity. The test cavity is respectively connected with the heater, the vibrator and the oil delivery device, the heater is used for heating the test cavity, the vibrator is used for generating vibration on the test cavity, and the oil delivery device is used for inputting transformer oil into the test cavity so as to generate oil pressure on the sealing element sample. The method is used for solving the problem that a large difference exists between test conditions and actual operation conditions of an existing accelerated aging test method for the transformer sealing element, the aging process of the sealing element under the combined action of oil pressure, temperature and vibration is simulated, and the test conditions are attached to actual conditions.

Description

Technical Field

[0001] The invention relates to the field of detection technology, and in particular to an aging test device and method for transformer sealing components under the combined action of multiple stresses. Background Art

[0002] Transformer equipment is a key equipment for electric energy conversion. The most common equipment form is oil-immersed transformer, which uses transformer oil as insulation and cooling medium. Once the transformer oil leaks, it will cause equipment performance failure or even failure. Transformer seal failure caused by seal aging is the main defect form of transformer, which poses a great threat to the safe and reliable operation of transformer equipment. Through the transformer oil seal aging test, the performance evaluation of transformer seals is carried out to obtain accurate information on the degree and speed of seal aging, which provides a basis for the replacement plan of transformer seals. It is necessary to control and improve maintenance efficiency, and avoid the situation where frequent seal replacement leads to waste of resources. Therefore, accurately simulating the seal aging process has great engineering value for obtaining accurate information on the degree and speed of seal aging.

[0003] The existing transformer oil seal aging test method is to immerse the seal sample in transformer oil and conduct an accelerated aging test for a certain period of time at a constant temperature. The temperature remains unchanged during the test. However, in actual operation of the transformer, the seal is subjected to the combined effects of heat, mechanical vibration and oil pressure. In addition to thermal stress, mechanical vibration and oil pressure may also cause the seal to fail prematurely.

[0004] The test conditions of the existing test method are significantly different from the actual operating conditions, and cannot fully simulate the aging and failure process of the seal. The specific differences are: (1) Due to the change in the transformer load rate, the transformer oil temperature rises and falls in a cycle, and the temperature cannot be maintained constant. The use of a constant temperature for accelerated aging tests cannot simulate the temperature alternation process; (2) Mechanical vibration occurs during the operation of the transformer, and the seal is actually in a vibrating state rather than the static state assumed in the existing test method. It is necessary to analyze the impact of vibration on the seal; (3) The seal is installed at different positions of the transformer and is subjected to different transformer oil pressures. It is necessary to consider the impact of oil pressure on seal failure. Summary of the invention

[0005] The present invention provides an aging test device and method for transformer seals under the combined action of multiple stresses, which are used to solve the problem that there is a large difference between the test conditions and the actual operating conditions of the existing accelerated aging test method for transformer seals, simulate the aging process of the seals under the combined action of oil pressure, temperature and vibration, and achieve the matching of the test conditions with the actual situation.

[0006] The present invention provides a transformer seal aging test device under multiple stress combined action, comprising:

[0007] Test chamber, heater, vibrator, oil feeder and seal specimen fixing structure,

[0008] The sealing sample fixing structure is arranged inside the test cavity.

[0009] The test cavity is connected to the heater, the vibrator and the oil delivery device respectively.

[0010] The heater is used to heat the test cavity, the vibrator is used to generate vibrations in the test cavity, and the oil feeder is used to feed transformer oil into the test cavity to generate oil pressure on the sealing component sample.

[0011] Furthermore, it is characterized in that it also includes an oil pressure measuring and controlling device, which is respectively connected to the test cavity and the oil transfer device, and is used to obtain the oil pressure value in the test cavity, and control the oil transfer device to output or input transformer oil according to the oil pressure value so that the oil pressure in the test cavity reaches a preset oil pressure value.

[0012] Furthermore, it also includes a temperature controller, which is connected to the test cavity and the heater respectively, and is used to obtain the temperature value in the test cavity, and control the working state of the heater according to the temperature value so that the temperature of the test cavity reaches a preset temperature value.

[0013] Furthermore, the heater is an electromagnetic heating coil, and the electromagnetic heating coil is equidistantly arranged outside the test cavity.

[0014] Furthermore, the sealing component sample fixing structure includes a groove arranged at the bottom of the test cavity, and the groove is used to place the sealing component sample.

[0015] Furthermore, the vibrator is a vibration test bench, and the vibration test bench is arranged at the bottom of the test cavity.

[0016] Furthermore, the oil delivery device comprises an oil inlet pipe and an oil outlet pipe, and the oil inlet pipe and the oil outlet pipe are connected to the test cavity together.

[0017] On the other hand, the present invention provides an aging test method for transformer seals under multiple combined stresses, comprising the following steps:

[0018] S1, input transformer oil into the test chamber until the oil pressure reaches a preset value;

[0019] S2, the heater heats the test cavity until the temperature reaches a preset value;

[0020] S3, the vibrator is started according to the preset vibration value;

[0021] S4. When the temperature, oil pressure and vibration parameters in the test cavity reach preset values ​​for a predetermined time, take out the sealing sample.

[0022] Further, including:

[0023] If the oil pressure in the test cavity is higher than the preset oil pressure value, outputting variable pressure oil from the test cavity until the preset oil pressure value is reached;

[0024] And / or if the temperature in the test chamber is higher than the preset temperature value, adjusting the heating temperature of the heater until the preset temperature value is reached.

[0025] Furthermore, the step S4 further includes:

[0026] S41, when the test cavity maintains the preset temperature value for a first preset time, turning off the heater to keep the temperature of the test cavity in a cooling state;

[0027] S42, when the cooling state of the test cavity is maintained for a second preset time, restarting the heater to heat the test cavity until the temperature reaches the preset value;

[0028] S43, repeat steps S41 and S42 until the sealing member sample is taken out.

[0029] It can be seen from the above technical solutions that the present invention has the following advantages:

[0030] The test cavity of the present invention is used to contain transformer oil, and the oil pressure in the test cavity is controlled by the change of the volume of the transformer oil in the test cavity, simulating the oil pressure environment of the seal in the transformer; the heater is used to heat the test cavity and then heat the transformer oil in the test cavity, simulating the temperature environment of the seal in the transformer; the vibrator vibrates the test cavity, simulating the mechanical vibration environment of the seal in the transformer. Therefore, the test device of this embodiment realizes the accelerated aging of the transformer seal under the combined action of the three stresses of heat, mechanical vibration and oil pressure, and the simulated test conditions are closer to the actual operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1The present invention is a schematic structural diagram of an aging test device for transformer seals under the combined action of multiple stresses.

[0033] Figure 2 The present invention is a flow chart of an aging test method for a transformer seal under the combined action of multiple stresses.

[0034] Figure 3 The present invention is a schematic diagram of the temperature control process in an aging test method for a transformer seal under the combined action of multiple stresses.

[0035] Description of the drawings: 1. Transformer oil sampling device; 2. Solenoid valve; 3. Solenoid pump; 4. Pipeline; 5. Test chamber; 6. Oil pressure sensor; 7. Temperature sensor; 8. Electromagnetic heating coil; 9. Sealing sample; 10. Vibration test bench; 11. Oil storage device; 12. Communication interface; 13. Data bus; 14. Control terminal. DETAILED DESCRIPTION

[0036] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and drawings of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the implementation of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] See also Figure 1 , Figure 1 An aging test device for transformer seals under multi-stress combined action provided by an embodiment of the present invention comprises a test cavity 5, a heater, a vibrator, an oil delivery device and a sealing sample 9 fixing structure.

[0039] The sealing sample fixing structure is inside the test cavity 5.

[0040] The test chamber 5 is connected to the heater, vibrator and oil delivery device respectively.

[0041] The heater is used to heat the sealing sample 9 , the vibrator is used to generate vibrations on the sealing sample 9 , and the oil feeder is used to input transformer oil into the test cavity 5 to generate oil pressure on the sealing sample 9 .

[0042] It can be understood that, in specific implementation, the test cavity 5 is used to contain transformer oil, and the oil pressure in the test cavity 5 is controlled by the change of the volume of the transformer oil in the test cavity 5, simulating the oil pressure environment of the seal in the transformer; the heater is used to heat the test cavity 5 and then heat the transformer oil in the test cavity 5, simulating the temperature environment of the seal in the transformer. The vibrator vibrates the test cavity 5 to simulate the mechanical vibration environment of the sealing piece in the transformer. Therefore, the test device of this embodiment realizes the accelerated aging of the transformer seal under the combined action of heat, mechanical vibration and oil pressure, and the simulated test conditions are closer to the actual operating conditions.

[0043] In a more specific embodiment, the test device also includes an oil pressure measuring and controlling device, which is respectively connected to the test cavity 5 and the oil transfer device. The oil pressure measuring and controlling device is used to obtain the signal of the oil pressure sensor 6 and control the oil transfer device to output or input transformer oil so that the oil pressure in the test cavity 5 reaches a preset oil pressure value.

[0044] In a more specific embodiment, the oil pressure monitor includes an oil pressure sensor 6, which is disposed at the top of the test cavity 5. It is understandable that the oil pressure sensor is disposed at the top of the test cavity 5, which can measure the oil pressure in the test cavity 5 while being minimally affected by the pressure of the transformer oil.

[0045] In a more specific embodiment, the oil delivery device includes an oil inlet pipeline, and the test cavity is connected to the transformer oil sampling device through the oil inlet pipeline. The solenoid valve 2 and the solenoid pump 3 are sequentially arranged on the oil inlet pipeline. The solenoid valve 2 is arranged on a side close to the transformer oil sampling device 1, and the solenoid pump 3 is arranged on a side close to the test cavity 5. In a specific implementation, the solenoid valve 2 and the solenoid pump 3 are sequentially opened to allow the transformer oil of the transformer oil sampling device 1 to be input into the test cavity 5, so as to increase the oil pressure in the test cavity 5.

[0046] In a more specific embodiment, the oil delivery device further includes an oil outlet pipeline, which is connected to the oil storage device 11, and an electromagnetic pump and an electromagnetic valve are provided in the oil storage device 11. In specific implementation, the transformer oil in the test cavity 5 can be input into the oil storage device 11, and the transformer oil in the test cavity 5 can be discharged, thereby achieving a decrease in the oil pressure in the test cavity 5.

[0047] It can be understood that, in specific implementation, when the oil pressure in the test chamber is low, by starting the electromagnetic pump 3 and the electromagnetic valve 2, the transformer oil in the transformer oil injection device 1 is input into the test chamber 5, so that the oil pressure in the test chamber 5 is increased. When the oil pressure in the test chamber 5 is low, by starting the oil storage device, the transformer oil in the test chamber 5 is output to the oil storage device 11, so that the oil pressure in the test chamber 5 is reduced. Therefore, this embodiment can achieve adjustable and controllable temperature in the test chamber 5, and ensure the accuracy of the oil pressure test conditions.

[0048] It can be understood that this embodiment realizes accelerated aging test of the seal under different oil pressures by separately setting up the oil inlet pipe and the oil outlet pipe, and cooperating with the oil pressure sensor 6, so as to simulate the seal being installed at different positions of the transformer or withstanding different oil pressures.

[0049] In a more specific embodiment, the test device also includes a temperature controller, which is connected to the temperature sensor 7 and the heater respectively. The temperature controller is used to obtain the signal of the temperature sensor 7, control the working state of the heater, and the temperature of the test chamber 5 reaches a preset temperature value.

[0050] In a more specific embodiment, the temperature measurement and control device further includes a temperature sensor, which is disposed at the top of the test cavity. It is understandable that the temperature sensor is disposed at the top of the test cavity, which can measure the temperature in the test cavity while being minimally affected by the pressure of the transformer oil.

[0051] In a more specific embodiment, the heater is an electromagnetic heating coil 8, which is arranged on the outside of the test cavity 5 to heat the oil inside the test cavity 5. During implementation, multiple layers of electromagnetic heating coils 8 can be arranged to be evenly distributed on the outer surface of the test cavity 5 to achieve uniform heating of the test cavity 5, reduce the difference in oil temperature at different locations of the test cavity 5, and avoid affecting the test results.

[0052] It is understandable that, in specific implementation, when the temperature in the test cavity is too high, the temperature in the test cavity is adjusted by changing the heating temperature of the electromagnetic heating coil 8. Therefore, this embodiment can achieve adjustable and controllable temperature in the test cavity 5, ensuring the accuracy of the temperature test conditions.

[0053] It should be noted that this embodiment is a combined aging test device, and its test environment is complex. During specific implementation, the temperature, oil pressure and mechanical vibration in the test chamber will also affect each other:

[0054] After transformer oil is input into the test cavity 5 until the preset oil pressure value is reached, the oil pressure will increase due to the influence of temperature during the process of heating the test cavity 5 by the heater. At this time, the oil pressure measurement and control device of this embodiment receives the oil pressure information in the test cavity in real time. When the oil pressure is too high, the oil pressure is reduced by outputting the transformer oil in the test cavity 5, and the oil pressure is maintained to reach the preset oil pressure value again, thereby overcoming the problem that the oil pressure is affected by temperature.

[0055] After starting the vibrator, on the one hand, the strong vibration of the transformer oil may cause partial discharge and other phenomena, and produce a small amount of gas. The presence of these gases in the oil may cause the oil pressure to change. If the gas is produced at a fast speed, it may cause the oil pressure to increase. On the other hand, the strong vibration of the transformer oil will cause the friction of the transformer oil molecules, and the heat will continue to accumulate, which may cause the temperature of the transformer oil to gradually rise. In this embodiment, the oil pressure and temperature are controlled in real time by the oil pressure controller and the temperature controller during the vibration of the test cavity 5, thereby overcoming the problem that the oil pressure and temperature are affected by mechanical vibration.

[0056] It should be noted that, since the purpose of the aging test of the seal is to quickly evaluate the quality and performance of the seal in a short period of time, the temperature preset value, oil pressure preset value and vibration preset value in the test are higher than the actual working conditions of the transformer. Once the preset values ​​are exceeded, there will be safety hazards. The device of this embodiment can monitor in real time whether the temperature, oil pressure and vibration can reach the preset values, and can ensure the safety of the aging test.

[0057] It should be noted that the present embodiment can accurately control the temperature, oil pressure and vibration parameters in the test chamber 5 to maintain them at preset values, ensure the accuracy of the test conditions and thereby obtain accurate test results for the seals, provide a basis for accurately estimating the service life of the seals, and achieve both control and improvement of maintenance efficiency and avoidance of waste of resources due to frequent replacement of seals.

[0058] In a more specific embodiment, the seal sample fixing structure includes a groove arranged at the bottom of the test cavity, and the groove is used to place the seal sample 9. In some specific implementations, the test cavity is composed of two parts, the upper part is a metal can body, and the lower part is a planar structure provided with a sealing groove, and the two parts are sealed and connected by a seal and fixed with fixing bolts. In some specific implementations, the groove can be a rectangular groove or a semicircular groove. It can be understood that the seal is fixed in the groove, and when the vibrator is started, it can vibrate synchronously with the test cavity. In some more specific implementations, the width of the groove is adjustable, which can prevent the aging failure characteristics of the seals in transformers of various types and sizes, and has a wide range of applications.

[0059] In a more specific embodiment, the vibrator is a vibration test bench 10, which is fixedly arranged at the bottom of the test cavity 5. It can be understood that, unlike the existing accelerated aging test method for seals under constant mechanical stress or without mechanical stress, this embodiment proposes to use a combination of the vibration test bench 10 and the test cavity 5, which can simulate the mechanical vibration borne by the transformer seal, is closer to the actual operating conditions, and can reflect the failure law of the seal under long-term repetitive vibration conditions.

[0060] In a more specific embodiment, the aging test device further includes a control terminal 14, which is respectively connected to the communication interface 12 on the solenoid valve 2, the solenoid pump 3, the oil pressure sensor 6, the temperature sensor 7, the electromagnetic heating coil 8, the vibration test bench 10 and the oil storage device 11 to realize automatic control. The control terminal 14 is electrically connected to the solenoid valve 2 and the electromagnetic pump 3 through the data bus 13 to control the start and stop of the solenoid valve 2 and the electromagnetic pump 3. The control terminal 14 is electrically connected to the oil pressure sensor 6 to monitor the oil pressure in the test cavity 5. The control terminal 14 is electrically connected to the temperature sensor 7 to monitor the temperature in the test cavity 5, and is electrically connected to the electromagnetic heating coil 8 to control the temperature in the test cavity 5 to reach a predetermined temperature. The control terminal is electrically connected to the communication interface 12 to control the oil storage device 11 to extract transformer oil from the test cavity 5 and reduce the oil pressure in the test cavity 5. The control terminal 14 is electrically connected to the vibration test bench 10 to control the vibration test bench 10 to vibrate according to a predetermined rule to simulate the vibration characteristics of the actual operation of the transformer.

[0061] It can be understood that the working principle of this embodiment is:

[0062] Under the action of the control terminal 14, the transformer oil medium enters the test cavity in a controllable manner through the transformer oil sampling device 1, the solenoid valve 2, the solenoid 3, and the pipeline 4. The oil pressure in the cavity is monitored by the oil pressure sensor 6 and then transmitted to the control terminal 14 for control. The temperature of the inside of the experimental cavity 5 is increased by the electromagnetic heating coil 8. The oil pressure in the cavity is monitored by the temperature sensor 7 and then transmitted to the control terminal 14 for control. The test cavity 5 is placed on the vibration test bench 10. The control terminal controls the vibration test bench 10 to simulate the mechanical vibration in the actual working condition. The seal sample 9 to be tested is installed in the groove at the bottom of the test cavity. The present invention realizes the controllable and adjustable temperature, vibration, and oil pressure in the test cavity 5 through the control terminal 14, the data bus 13, the temperature sensor 7, the oil pressure sensor 6, and the vibration test bench 10. It can simulate the accelerated aging process of the transformer seal under the actual operating conditions under the combined effects of multiple factors such as temperature, mechanical vibration, and oil pressure, and the simulated test conditions are closer to the actual operating conditions.

[0063] In some more specific embodiments:

[0064] The oil pressure preset value and temperature preset value are both range values. The oil pressure preset value is 0.1-0.8MPa, and the temperature preset value is 40-105℃;

[0065] The vibration preset value includes the amplitude preset value and the vibration frequency preset value. The amplitude preset value is 2mm, and the vibration frequency preset value is 30Hz.

[0066] Solenoid valve 2 is a solenoid valve controlled by analog signal, and the control signal is 4-20mA analog signal;

[0067] Electromagnetic pump 3 is a 100W plunger pump, and the control signal is a 4-20mA analog signal;

[0068] Pipe 4 is a corrosion-resistant stainless steel pipe with a diameter of 6 mm. Other Teflon and copper materials that are resistant to transformer oil corrosion can also meet the requirements;

[0069] The test chamber 5 is preferably made of 316 stainless steel, which is resistant to transformer oil corrosion;

[0070] The oil pressure sensor 6 preferably has a test range of 0-1MPa and supports a pressure sensor for digital signals. The digital signal adopts ModBus_RTU communication protocol and RS-485 physical interface;

[0071] The temperature sensor 7 preferably has a test range of 0-150°C, a measurement accuracy of 0.5°C, and a pressure sensor that supports digital signals. The digital signal adopts ModBus_RTU communication protocol and RS-485 physical interface;

[0072] The sealing sample 9 preferably adopts O-ring, other rubber strips and special-shaped parts can also meet the requirements

[0073] The oil storage device 11 is a stainless steel oil storage tank, preferably with a volume of 5L;

[0074] The control terminal 14 includes a laptop computer, an industrial computer, etc., and an industrial computer with rich interfaces is preferred.

[0075] The second aspect of the present invention discloses a sealing component aging test method under the combined action of multiple stresses, using the above-mentioned device, comprising the following steps:

[0076] S1, inputting transformer oil into the test chamber 5 until the oil pressure reaches the preset value;

[0077] S2, the heater heats the test cavity 5 until the temperature reaches a preset value;

[0078] S3, the vibrator is started according to the preset vibration value;

[0079] S4. When the temperature, oil pressure and vibration parameters in the test cavity 5 reach preset values ​​for a predetermined time, the sealing component sample 9 is taken out.

[0080] It can be understood that the above steps realize the accelerated aging process of the transformer seal under the combined effects of heat, mechanical vibration and oil pressure.

[0081] In a more specific embodiment, in the above steps S1-S4, if the oil pressure in the test chamber 5 is higher than the preset oil pressure value, transformer oil is output from the test chamber until the oil pressure reaches the preset oil pressure value; and / or if the temperature in the test chamber is higher than the preset temperature value, the heating temperature of the heater is adjusted until the preset temperature value is reached.

[0082] It can be understood that the temperature and oil pressure of this embodiment are controllable and adjustable, so as to achieve: the simulated test conditions are closer to the actual operating conditions; overcome the problem that the temperature, oil pressure and mechanical vibration in the test chamber will also affect each other; ensure the safe conduct of the aging test; accurately control the temperature, oil pressure and vibration parameters in the test chamber 5 to maintain them at preset values, ensure the accuracy of the test conditions and obtain accurate test results for the seals, provide a basis for accurately estimating the service life of the seals, and achieve both control and improvement of maintenance efficiency and avoidance of waste of resources caused by frequent replacement of seals.

[0083] In a more specific embodiment, step S4 further includes:

[0084] S41, when the temperature of the test cavity is maintained for a first preset time, turning off the heater to keep the temperature of the test cavity in a cooling state;

[0085] S42, when the temperature of the test cavity is in the cooling state for a second preset time, restarting the heater to heat the test cavity until the temperature reaches a preset value;

[0086] S43, repeat steps S41 and S42 until the sealing member sample is taken out.

[0087] It can be understood that, unlike the existing accelerated aging test method for seals at a constant temperature, the accelerated aging test method proposed in the present invention simulates the thermal cycle process of heating and cooling of seals in actual operation of the transformer, which is closer to the actual operating conditions.

[0088] See also Figure 2 In some more specific embodiments, a method for testing seal aging under combined effects of multiple stresses is provided.

[0089] (1) The control terminal sends an analog signal command through the data bus 13 to start the solenoid valve 2;

[0090] (2) The control terminal 14 sends an analog signal command through the data bus 13 to control the electromagnetic pump 3, and uses the electromagnetic pump 3 to drive the transformer oil into the test chamber 5;

[0091] (3) The control terminal 14 communicates with the oil pressure sensor 6 via the data bus 13 to monitor the oil pressure inside the test chamber 5;

[0092] (4) When the oil pressure inside the test chamber 5 reaches the predetermined oil pressure, the control terminal 14 issues a command to close the solenoid valve 2 and the solenoid pump 3 in sequence; if the oil pressure sensor 6 detects that the oil pressure inside the test chamber 5 is higher than the predetermined oil pressure, the control terminal 14 issues a command to control the oil storage device 11 to extract transformer oil from the test chamber 5 to reduce the oil pressure inside the test chamber 5 until it reaches the predetermined oil pressure;

[0093] (5) The control terminal 14 communicates with the temperature sensor 7 via the data bus 13 to monitor the temperature in the test chamber 5;

[0094] (6) Simulate the load variation and oil temperature variation of the transformer in actual operation (see Figure 3 ), a heating and cooling process is presented within a 24-hour load cycle, and a control terminal 14 is used to issue an instruction to control the electromagnetic heating coil 8 to heat for a predetermined time tr and stop heating for a time td, so as to realize the cyclic rise and fall of the transformer oil temperature;

[0095] It is understandable that the temperature of the transformer in actual operation changes periodically with the power load. During the daytime peak power consumption and the higher ambient temperature, the internal temperature of the transformer is at a high temperature; at night, the temperature follows the power consumption trough and the lower ambient temperature, and the internal temperature of the transformer is at a relatively low temperature. Under such temperature cycle conditions, the seal will undergo cyclic alternating compression deformation. This embodiment considers the temperature cycle within 24 hours of a natural day (Tr+Td=24h), which is closer to the actual working conditions and is suitable for transformer seals operating in various regions, not just seals in plateau areas. The temperature loading conditions proposed in this embodiment are a gradual heating and natural cooling process, which reflects the actual thermal stress that the seal can withstand.

[0096] (7) The control terminal 14 communicates with the vibration test bench 10 to control the vibration test bench 10 to operate according to predetermined vibration characteristics, thereby simulating the vibration frequency and amplitude to which the seal is subjected during actual operation of the transformer;

[0097] (8) When the temperature, vibration and oil pressure in the test cavity 5 reach the preset conditions, the seal in the test cavity 5 is kept under accelerated aging under the three stress conditions of heat, vibration and oil pressure for a predetermined time, and the seal sample is taken out;

[0098] (9) Carry out performance testing of seals after aging, test the compression permanent deformation, quality, Shore hardness and other parameters of the seals, and evaluate the degree of aging of the seals;

[0099] (10) The experiment is over.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transformer seal aging test device under multiple stress combined action, characterized in that: include: Test chamber, heater, vibrator, oil feeder and seal specimen fixing structure, The sealing sample fixing structure is arranged inside the test cavity. The test cavity is connected to the heater, the vibrator and the oil delivery device respectively. The heater is used to heat the test cavity, the vibrator is used to generate vibrations in the test cavity, and the oil feeder is used to feed transformer oil into the test cavity to generate oil pressure on the sealing component sample.

2. The aging test device for transformer seals under multiple combined stresses according to claim 1 is characterized in that: It also includes an oil pressure measuring and controlling device, which is respectively connected to the test cavity and the oil delivery device, and is used to obtain the oil pressure value in the test cavity, and control the oil delivery device to output or input transformer oil according to the oil pressure value so that the oil pressure in the test cavity reaches a preset oil pressure value.

3. A transformer seal aging test device under multiple stress combined action according to claim 1 or 2, characterized in that: It also includes a temperature controller, which is connected to the test cavity and the heater respectively. The temperature controller is used to obtain the temperature value in the test cavity and control the working state of the heater according to the temperature value so that the temperature of the test cavity reaches a preset temperature value.

4. The aging test device for transformer seals under multiple combined stresses according to claim 1 is characterized in that: The heater is an electromagnetic heating coil, and the electromagnetic heating coil is equidistantly arranged outside the test cavity.

5. The aging test device for transformer seal under multiple stress combined action according to claim 1 is characterized in that: The sealing component sample fixing structure comprises a groove arranged at the bottom of the test cavity, and the groove is used for placing the sealing component sample.

6. The aging test device for transformer seal under multiple stress combined action according to claim 1 is characterized in that: The vibrator is a vibration test bench, and the vibration test bench is arranged at the bottom of the test cavity.

7. The aging test device for transformer seal under multiple combined stresses according to claim 1 is characterized in that: The oil delivery device comprises an oil inlet pipe and an oil outlet pipe, and the oil inlet pipe and the oil outlet pipe are connected to the test cavity together.

8. A transformer seal aging test method under multiple stress combined action based on the device of claim 1, characterized in that: The steps include: S1, input transformer oil into the test chamber until the oil pressure reaches a preset value; S2, the heater heats the test cavity until the temperature reaches a preset value; S3, the vibrator is started according to the preset vibration value; S4. When the temperature, oil pressure and vibration parameters in the test cavity reach preset values ​​for a predetermined time, take out the sealing sample.

9. A transformer seal aging test method under multiple stress combined action according to claim 8, characterized in that: include: If the oil pressure in the test cavity is higher than the preset oil pressure value, outputting variable pressure oil from the test cavity until the preset oil pressure value is reached; And / or if the temperature in the test chamber is higher than the preset temperature value, adjusting the heating temperature of the heater until the preset temperature value is reached.

10. A transformer seal aging test method under multiple stress combined action according to claim 8 or 9, characterized in that: The step S4 further comprises: S41, when the test cavity maintains the preset temperature value for a first preset time, turning off the heater to keep the temperature of the test cavity in a cooling state; S42, when the cooling state of the test cavity is maintained for a second preset time, restarting the heater to heat the test cavity until the temperature reaches the preset value; S43, repeat steps S41 and S42 until the sealing member sample is taken out.

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