Insulator stress detection device and method in piezothermal coupling field

Abstract

The invention discloses an insulator stress detection device and method in a piezothermal coupling field, and the device comprises an ultrasonic guided wave generation receiver which is used for generating and receiving an ultrasonic guided wave signal; the data acquisition and analysis system is connected with the ultrasonic guided wave generation receiver and is used for recording and analyzing the ultrasonic guided wave signal; the ultrasonic guided wave detection unit is arranged on the surface of the insulator, and the ultrasonic guided wave detection unit is connected with the ultrasonic guided wave generation receiver; gas-insulated metal-enclosed transmission line equipment (GIL equipment for short); a large current generating device; a temperature detection unit; a pressure detection unit; according to the device and the method for detecting the insulator stress, the sensitivity of detecting the insulator stress is improved, and the device and the method for detecting the insulator stress are closer to practical application.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic guided wave nondestructive testing technology, and more specifically to an insulator stress detection device and method under a pressure-thermal coupling field. Background Technology

[0002] Currently, gas-insulated switchgear (GIS) is widely used in substations due to its advantages such as small footprint, high reliability, short installation cycle, and long maintenance cycle. The quality of GIS pot-type insulators has a decisive impact on the overall quality of GIS. As the most important insulating component in GIS, pot-type insulators play a role in electrical insulation, gas sealing, shell reinforcement, and support. In actual production and live operation, factors such as improper product manufacturing process control, uneven stress distribution of bolts at flanges, electric field strength, and temperature changes can cause deformation and cracking of pot-type insulators, leading to GIS leakage, partial discharge, or even insulator surface flashover, resulting in large-scale power outages. Therefore, crack detection of pot-type insulators is of great significance for the safe operation of GIS.

[0003] Currently, insulator stress testing faces two main challenges. Firstly, common stress testing methods each have their limitations. Destructive stress testing methods, such as blind hole methods and segmentation methods, are unsuitable for in-service equipment and components, or for specialized or expensive materials due to their destructive nature. The most widely used non-destructive testing method for stress is X-ray diffraction, but it has high material requirements (isotropic, homogeneous, fine-grained polycrystalline materials) and drawbacks such as complex operation, numerous testing limitations, and excessively long single-point testing times. Therefore, non-destructive stress testing remains a challenging problem. Secondly, regardless of the method used, the devices manufactured simply test the stress of insulators under normal temperature, pressure difference, and stress-free environments, rarely considering the stress conditions of insulators under integrated electrothermal coupling fields. In reality, during the operation of GIS equipment, changes in temperature and pressure significantly affect the stress distribution of insulators.

[0004] Therefore, how to provide an insulator mechanical stress detection device that can solve the above problems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides an insulator stress detection device and method under a pressure-thermal coupling field. The device can realize the mechanical stress detection of pot-type insulators under a pressure-thermal coupling field and has strong engineering application value.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A device for detecting insulator stress under a pressure-thermal coupling field, characterized in that it comprises:

[0008] Ultrasonic guided wave generator and receiver (1);

[0009] The data acquisition and analysis system (2) is connected to the ultrasonic guided wave generator receiver (1) and is used to process the ultrasonic guided wave signals received under different temperatures and pressure differences between the two air chambers to obtain the corresponding ultrasonic guided wave signal group velocity change and realize the mechanical stress detection of the insulator.

[0010] An ultrasonic guided wave detection unit (3) is disposed on the surface of the insulator and connected to the ultrasonic guided wave generator receiver (2);

[0011] The gas chamber (4) refers to the inside of the GIS shell, which is filled with SF6 insulating gas;

[0012] Gas-insulated metal-enclosed transmission line equipment (GIL) (5) is used for transmitting, measuring and protecting current; the GIL equipment (5) includes a guide rod (51) and a GIL housing (52);

[0013] The basin-type insulator (6) is the insulator to be tested;

[0014] A high current generator (7) is used to supply current to the GIL device (5);

[0015] A temperature detection unit (8) is installed on the inner wall of the insulator and includes at least two temperature sensors for monitoring the temperature of the insulator.

[0016] The pressure detection unit (9) is installed inside the GIL device (5) and is used to monitor the gas pressure on both sides of the insulator.

[0017] Preferably, the ultrasonic guided wave detection unit (3) includes a signal excitation end (31) and a signal receiving end (32), and both the signal excitation end (31) and the corresponding signal receiving end (32) are connected to the ultrasonic guided wave generator (2).

[0018] The signal excitation end (31) is used to receive ultrasonic guided wave signals and excite ultrasonic guided waves in the insulator to be tested. The signal receiving end (32) is used to receive ultrasonic guided wave signals and send them to the data acquisition and analysis system (2) through the ultrasonic guided wave generator receiver (1). Preferably, the air chamber (4) includes air chambers (41) and air chambers (42) on both sides of the insulator, which are respectively filled with insulating gas SF6 at a specified pressure.

[0019] This invention also discloses a method for detecting insulator stress under a pressure-thermal coupling field, comprising the above-mentioned insulator stress detection device under a pressure-thermal coupling field, characterized by comprising the following steps:

[0020] Step 1: Fill the gas chamber (4) with SF6 gas, measure the pressure of the two gas chambers respectively by the pressure detection unit (9), and send the data to the data acquisition and analysis system (2);

[0021] Step 2: The high current generating device (7) passes current through the guide rod (52), and the temperature detection unit (7) measures the temperature of the guide rod (52) and sends it to the data acquisition and analysis system (2);

[0022] Step 3: The ultrasonic guided wave generator receiver (1) generates an ultrasonic guided wave signal;

[0023] Step 4: The ultrasonic guided wave detection unit (3) collects the ultrasonic guided wave signal generated by the insulator and sends it to the data acquisition and analysis system (2);

[0024] Step 5: The data acquisition and analysis system (2) processes the ultrasonic guided wave signal under the temperature and pressure difference between the two air chambers to obtain the corresponding ultrasonic signal group velocity change rate, thereby realizing the mechanical stress detection of the insulator.

[0025] Preferably, step 4 further includes the following:

[0026] The ultrasonic detection unit (3) includes a signal excitation end (31) and a signal receiving end (32);

[0027] The signal excitation end (31) excites an ultrasonic guided wave signal in the insulator, and the signal receiving end (32) is used to receive the ultrasonic guided wave signal and send it to the data acquisition and analysis system (2) through the ultrasonic guided wave generator and receiver (1).

[0028] Preferably, the data acquisition and analysis system (2) obtains the rate of change of ultrasonic guided wave signal group velocity under different temperatures and pressure differences, and uses this as a characteristic quantity to further obtain the stress concentration of the insulator; the calculation expression of the rate of change of ultrasonic guided wave signal group velocity η is:

[0029]

[0030] In the formula, cga and cg0 are the group velocities of the transducer output signals under stress and without stress, respectively.

[0031] Beneficial effects

[0032] Insulating gases of different pressures are filled into the two chambers. A high-current generator energizes the guide rod, causing it to heat up and expand. An ultrasonic guided wave signal is generated using an ultrasonic guided wave generator and receiver. This ultrasonic guided wave is applied to the insulator by a detection unit. The receiving sensor transmits the ultrasonic guided wave signal, carrying insulator status information, to the data acquisition and analysis system via the ultrasonic guided wave generator and receiver. The ultrasonic guided wave group velocity is calculated based on the ultrasonic guided wave response signal. Using this as a characteristic quantity and the ultrasonic guided wave detection signal of a intact basin-type insulator as a benchmark, the relative rate of change of the ultrasonic guided wave signal group velocity is further calculated. The group velocity of the ultrasonic guided wave signal has an inverse linear relationship with the stress magnitude. Based on this linear relationship, the mechanical stress of the basin-type insulator can be detected. This detection method considers the influence of the pressure-thermal coupling field on the mechanical stress of the insulator, improves the sensitivity of ultrasonic guided wave detection of mechanical stress, and has strong engineering application value. Attached Figure Description

[0033] To further clarify the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are merely embodiments of the present invention.

[0034] Figure 1 The attached figure is a structural diagram of the insulator stress detection device under a pressure-thermal coupling field provided by the present invention;

[0035] Figure 2 The attached figure is a flowchart of an insulator stress detection method under a pressure-thermal coupling field provided by the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] See appendix Figure 1 As shown, this invention discloses an insulator stress detection device and method under a pressure-thermal coupling field, comprising:

[0038] Ultrasonic guided wave generator and receiver;

[0039] A data acquisition and analysis system, wherein the data acquisition and analysis system is connected to an ultrasonic guided wave generator and receiver, the ultrasonic guided wave generator and receiver being used to generate ultrasonic guided wave signals;

[0040] An ultrasonic guided wave detection unit is disposed on the surface of an insulator and is connected to an ultrasonic guided wave generator and receiver.

[0041] The air chamber is the portion of the insulator filled with SF6 on both sides;

[0042] A high-current generating device, which is used to energize the guide rod;

[0043] A temperature detection unit is installed on the inner wall of the insulator and is connected to a data acquisition and analysis system.

[0044] A pressure detection unit is installed in the air chamber and is used to detect the pressure in the air chambers on both sides of the insulator.

[0045] In one specific embodiment, insulating gases at different pressures are filled into the air chambers on both sides of the insulator. The pressure detection unit measures and records the field strength and sends the pressure to the data acquisition and analysis system.

[0046] In one specific embodiment, a high-current generator is used to energize the guide rod, and a temperature detection unit is used to detect the temperature of the guide rod and send the temperature data to a data acquisition and analysis system.

[0047] In one specific embodiment, the ultrasonic guided wave detection unit 3 includes a signal excitation end 31 and a signal receiving end 32, both of which are connected to the ultrasonic guided wave generator receiver 1.

[0048] The signal excitation end 31 is used to receive ultrasonic guided wave signals and excite ultrasonic guided waves in the insulator to be tested. The signal receiving end 32 is used to receive ultrasonic guided wave signals and send them to the data acquisition and analysis system 2 through the ultrasonic guided wave generator receiver 1.

[0049] In one specific embodiment, the data acquisition and analysis system 2 processes the ultrasonic guided wave signals received under different temperatures and pressure differences to obtain the relative rate of change of the ultrasonic guided wave signal group velocity, thereby realizing the mechanical stress detection of the insulator.

[0050] Further details can be found in the appendix. Figure 2 As shown, this embodiment of the invention also provides a method for detecting insulator stress under a pressure-thermal coupling field using any of the above-mentioned methods, comprising:

[0051] Gas chambers 41 and 42 are filled with insulating gases at different pressures. The pressure detection unit detects the pressure in both gas chambers and sends the data to the data analysis and acquisition system.

[0052] A high-current generator supplies power to the guide rod, and a temperature detection unit detects the temperature of the guide rod and sends the temperature to the data acquisition and analysis system.

[0053] An ultrasonic guided wave generator and receiver produces ultrasonic guided wave signals;

[0054] The ultrasonic guided wave detection unit 3 collects the ultrasonic guided wave signal generated on the surface of the insulator and sends it to the data acquisition and analysis system 2;

[0055] The data acquisition and analysis system 2 processes the ultrasonic guided wave signals under the temperature and pressure difference to obtain the relative change rate of the group velocity of the corresponding ultrasonic guided wave signals, thereby realizing the mechanical stress detection of the insulator.

[0056] In one specific embodiment, the process of acquiring the ultrasonic guided wave signal generated on the surface of the insulator is as follows:

[0057] The ultrasonic guided wave detection unit 3 includes a signal excitation end 31 and a signal receiving end 32;

[0058] The signal excitation terminal 31 receives the signal generated by the ultrasonic guided wave generator and receiver and excites the ultrasonic guided wave signal in the insulator. The signal receiving terminal 32 is used to receive the ultrasonic guided wave signal and send it to the data acquisition and analysis system 2 through the ultrasonic guided wave generator and receiver.

[0059] In one specific embodiment, the data acquisition and analysis system 2 obtains the corresponding group velocity based on the ultrasonic guided wave signal, and uses this as a characteristic quantity to further obtain the relative rate of change of the ultrasonic guided wave signal group velocity.

[0060] In a specific embodiment, the specific expression for the rate of change of the ultrasonic guided wave signal group velocity is as follows:

[0061]

[0062] In the formula, c ga and c g0 These are the group velocities of ultrasonic guided wave signals under stress and at room temperature without stress, respectively.

[0063] Specifically, the specific expression for the ultrasonic guided wave signal group velocity is:

[0064]

[0065] In the formula, x2 and x1 represent the positions of the ultrasonic guided wave signal peaks at t2 and t1, respectively. The above describes and illustrates the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A device for detecting insulator stress under a pressure-thermal coupling field, characterized in that, include: Ultrasonic guided wave generator and receiver (1); The data acquisition and analysis system (2) is connected to the ultrasonic guided wave generator receiver (1) and is used to process the ultrasonic guided wave signals received under different temperatures and pressure differences between the two air chambers to obtain the corresponding ultrasonic guided wave signal group velocity change and realize the mechanical stress detection of the insulator. An ultrasonic guided wave detection unit (3) is disposed on the surface of the insulator and connected to the ultrasonic guided wave generator receiver (2); The gas chamber (4) refers to the inside of the GIS shell, which is filled with SF6 insulating gas; Gas-insulated metal-enclosed transmission line equipment (GIL) (5) is used for transmitting, measuring and protecting current; the GIL equipment (5) includes a guide rod (51) and a GIL housing (52); The basin-type insulator (6) is the insulator to be tested; A high current generator (7) is used to supply current to the GIL device (5); A temperature detection unit (8) is installed on the inner wall of the insulator and includes at least two temperature sensors for monitoring the temperature of the insulator. The pressure detection unit (9) is installed inside the GIL device (5) and is used to monitor the gas pressure on both sides of the insulator.

2. The insulator stress detection device under a pressure-thermal coupling field according to claim 1, characterized in that, The ultrasonic guided wave detection unit (3) includes a signal excitation end (31) and a signal receiving end (32), and both the signal excitation end (31) and the corresponding signal receiving end (32) are connected to the ultrasonic guided wave generator (2). The signal excitation end (31) is used to receive ultrasonic guided wave signals and excite ultrasonic guided waves in the insulator to be tested. The signal receiving end (32) is used to receive ultrasonic guided wave signals and send them to the data acquisition and analysis system (2) through the ultrasonic guided wave generator receiver (1).

3. The insulator stress detection device under a pressure-thermal coupling field according to claim 1, characterized in that, The gas chamber (4) includes gas chambers (41) and gas chambers (42) on both sides of the insulator, which are filled with insulating gas SF6 at a specified pressure.

4. A method for detecting insulator stress under a pressure-thermal coupling field, comprising the insulator stress detection device under a pressure-thermal coupling field as described in claim 1, characterized in that, Includes the following steps: Step 1: Fill the gas chamber (4) with SF6 gas, measure the pressure of the two gas chambers respectively by the pressure detection unit (9), and send the data to the data acquisition and analysis system (2); Step 2: The high current generating device (7) passes current through the guide rod (52), and the temperature detection unit (7) measures the temperature of the guide rod (52) and sends it to the data acquisition and analysis system (2); Step 3: The ultrasonic guided wave generator receiver (1) generates an ultrasonic guided wave signal; Step 4: The ultrasonic guided wave detection unit (3) collects the ultrasonic guided wave signal generated by the insulator and sends it to the data acquisition and analysis system (2); Step 5: The data acquisition and analysis system (2) processes the ultrasonic guided wave signal under the temperature and pressure difference between the two air chambers to obtain the corresponding ultrasonic signal group velocity change rate, thereby realizing the mechanical stress detection of the insulator.

5. The method for detecting insulator stress under a pressure-thermal coupling field according to claim 4, characterized in that, Step 4 further includes the following: The ultrasonic detection unit (3) includes a signal excitation end (31) and a signal receiving end (32); The signal excitation end (31) excites an ultrasonic guided wave signal in the insulator, and the signal receiving end (32) is used to receive the ultrasonic guided wave signal and send it to the data acquisition and analysis system (2) through the ultrasonic guided wave generator and receiver (1).

6. The method for detecting insulator stress under a pressure-thermal coupling field according to claim 4, characterized in that, The data acquisition and analysis system (2) obtains the rate of change of ultrasonic guided wave signal group velocity under different temperatures and pressure differences, and uses this as a characteristic quantity to further obtain the stress concentration of the insulator; the calculation expression of the rate of change of ultrasonic guided wave signal group velocity η is: In the formula, cga and cg0 are the group velocities of the transducer output signals under stress and without stress, respectively.

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