A Verification Method and System for GIS UHF Built-in Sensors Based on Calculated Equivalent Height

Abstract

This invention relates to a calibration method for UHF built-in sensors in GIS (Gas-Insulated Switchgear) devices based on the calculation of equivalent height, aiming to solve the problem of difficult calibration and verification of built-in sensors in the verification of GIS partial discharge devices. This method indirectly calculates the equivalent height of the built-in sensor by measuring the equivalent height of a easily detachable external sensor, combining the general attenuation law of UHF electromagnetic waves within the GIS with the output voltages of the external and built-in sensors at the same location under the same pulse, and completes the verification based on the mean and minimum values ​​of the equivalent height. This solves the problem of difficult calibration of UHF built-in sensors for partial discharge.

Description

Technical Field

[0001] This invention relates to the field of partial discharge technology for GIS equipment, and more particularly to a method and system for verifying a built-in UHF sensor in GIS. Background Technology

[0002] Ultra-high frequency (UHF) sensors are widely used in detecting partial discharge in gas-insulated switchgear (GIS) due to their advantages such as high accuracy, high sensitivity, and resistance to interference. However, although the calibration technology for UHF sensors is relatively mature, there is still no unified and efficient calibration method for GIS UHF sensors, either domestically or internationally.

[0003] Equivalent height It is the frequency domain voltage output by the antenna. With the received frequency domain electric field The ratio of the frequency domain voltage outputs of the sensor to the reference sensor reflects the coupling characteristics of the sensor and has become an important indicator for evaluating ultra-high frequency (UHF) sensors. During measurement, the sensor under test (SDS) and the reference sensor are placed together on the upper third of the GTEM chamber where the electric field strength is relatively uniform. Since the equivalent height of the reference sensor is known, the equivalent height of the SDS can be indirectly calculated based on the ratio of the frequency domain voltage outputs of the SDS and the reference sensor.

[0004] There are three types of UHF sensors used for partial discharge detection in GIS: built-in, open basin, and cast-hole. Built-in sensors are pre-installed at the manhole and cannot be removed while energized after the GIS is put into operation, nor can they be disassembled for calibration in the GTEM (Geometric Compatibility) chamber. This makes the calibration of built-in sensors the most difficult. Based on the indirect calculation principle in GTEM, the equivalent height of the built-in sensor can be indirectly calculated using the measured equivalent height of the external sensor and the attenuation characteristics of electromagnetic waves in the GIS. The calculated equivalent height value serves as an important evaluation criterion for the calibration of UHF sensors in GIS. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to verify the ultra-high frequency built-in sensor for partial discharge.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The verification method for GIS UHF built-in sensors based on calculated equivalent height includes the following steps:

[0008] The first step is to measure the frequency domain equivalent height of a standard external sensor. ;

[0009] The second step is to measure the inner diameter of the GIS. aand the radius of the basin insulator r Therefore, the frequency domain attenuation of ultra-high frequency electromagnetic waves leaking from the basin insulator can be calculated.

[0010] The third step is to measure the distance between the UHF built-in sensor at the GIS handhole and the GIS housing. d Calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when they pass through a circular waveguide with a built-in handhole;

[0011] The fourth step is to complete the connection and wiring of the experimental setup, including placing the standard external sensor close to the basin insulator closest to the built-in sensor to be calibrated, connecting the pulse generator, and connecting the interface between the sensor and the oscilloscope.

[0012] Fifth, inject a standard double-exponential voltage pulse of a certain amplitude and frequency into an external sensor adjacent to the built-in sensor to be calibrated, and measure the output voltage of the built-in sensor. and standard external sensor output voltage ;

[0013] Step 6: Calculate the frequency domain equivalent height of the built-in sensor. ;

[0014] Step 7: Calculate the mean value of the frequency domain equivalent height of the built-in sensor. and minimum value According to the mean and minimum value Determine the sensitivity of the UHF built-in sensor.

[0015] Furthermore, the first step includes the following specific operations:

[0016] S101: Place the standard external sensor at the opening where the field strength is more concentrated on the rear third of the upper surface of the GTEM chamber;

[0017] S102: Inject a double-exponential ultra-high frequency pulse signal into the GTEM cell;

[0018] S103: The frequency domain equivalent height of the standard external sensor was obtained from the background measurement. .

[0019] Furthermore, the second step includes the following specific operations:

[0020] S201: Measure the inner diameter of this GIS a and the radius of the basin insulator at any position r ;

[0021] S202: Substitute into the formula to calculate the frequency domain attenuation of the ultra-high frequency electromagnetic wave when it passes through the basin insulator:

[0022] .

[0023] Furthermore, the third step includes the following operations:

[0024] S301: Measure the horizontal distance between the lead wire of the built-in sensor to be calibrated and the outer wall of the GIS. d ;

[0025] S302: Substitute into the formula to calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when passing through a hand-hole circular waveguide:

[0026] .

[0027] Furthermore, the fourth step includes the following operations:

[0028] S401: Place the standard external sensor, calibrated by the GTEM cell, close to the basin insulator that is radially closest to the internal sensor to be calibrated;

[0029] S402: Use the sensor adjacent to the built-in sensor to be calibrated as the injection sensor, and connect the handheld pulse generator to the power supply port of the injection sensor;

[0030] S403: Connect the interfaces of the built-in sensor to be calibrated and the standard external sensor to CH1 and CH2 of the high-speed oscilloscope, respectively;

[0031] S404: The sensor is wrapped in tin foil to prevent the signal from propagating through the outside air and affecting the test results.

[0032] Furthermore, the fifth step includes the following operations:

[0033] S501: Turn on the handheld pulse generator switch and inject a standard double-exponential voltage pulse of a certain amplitude and frequency into the external sensor adjacent to the built-in sensor to be calibrated; repeatedly adjust to ensure that the injected voltage pulse can simulate the ultra-high frequency electromagnetic wave signal excited by partial discharge;

[0034] S502: Measures the frequency domain response voltage of the built-in sensor. Response voltage in the frequency domain of a standard external sensor .

[0035] Furthermore, the formula for calculating the frequency domain equivalent height of the built-in sensor in step six is ​​as follows:

[0036] .

[0037] This invention also provides a verification system for GIS UHF built-in sensors based on calculated equivalent height, comprising:

[0038] The first measurement module is used to measure the frequency domain equivalent height of a standard external sensor. ;

[0039] The second measurement module is used to measure the inner diameter of the GIS. a and the radius of the basin insulator r Therefore, the frequency domain attenuation of ultra-high frequency electromagnetic waves leaking from the basin insulator can be calculated.

[0040] The third measurement module is used to measure the distance between the UHF built-in sensor at the GIS handhole and the GIS housing. d Calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when they pass through a circular waveguide with a built-in handhole;

[0041] The experimental module completes the connection and wiring of the experimental device, including attaching the standard external sensor to the basin insulator closest to the built-in sensor to be calibrated, connecting the pulse generator, and connecting the interface between the sensor and the oscilloscope.

[0042] The fourth measurement module is used to inject a standard double-exponential voltage pulse of a certain amplitude and frequency into an external sensor adjacent to the built-in sensor to be calibrated, and to measure the output voltage of the built-in sensor. and standard external sensor output voltage ;

[0043] The first calculation module calculates the frequency domain equivalent height of the built-in sensor. ;

[0044] The second calculation module calculates the mean value of the frequency domain equivalent height of the built-in sensor. and minimum value According to the mean and minimum value Determine the sensitivity of the UHF built-in sensor.

[0045] Furthermore, the fourth measurement module includes the following operations:

[0046] S501: Turn on the handheld pulse generator switch and inject a standard double-exponential voltage pulse of a certain amplitude and frequency into the external sensor adjacent to the built-in sensor to be calibrated; repeatedly adjust to ensure that the injected voltage pulse can simulate the ultra-high frequency electromagnetic wave signal excited by partial discharge;

[0047] S502: Measures the frequency domain response voltage of the built-in sensor. Response voltage in the frequency domain of a standard external sensor .

[0048] Furthermore, the formula for calculating the frequency domain equivalent height of the built-in sensor in the first calculation module is as follows:

[0049] .

[0050] The advantages of this invention are:

[0051] This invention innovatively proposes a scheme for calibrating UHF built-in sensors based on the calculated equivalent height of the sensor in the frequency domain. Since the pre-installed built-in sensor cannot be removed from the operational GIS, it cannot be placed in a GTEM cell to calculate its equivalent height. Therefore, an external sensor calibrated in the GTEM cell is used to indirectly calculate the equivalent height of the built-in sensor. A standard external sensor is placed in close proximity to the basin insulator adjacent to the built-in sensor to be calibrated. An equivalent artificial pulse is injected into the external sensor adjacent to the built-in sensor to be calibrated. The frequency domain voltages output by the built-in sensor and the standard external sensor can be obtained, and their ratio can be calculated. Simultaneously, the simulated UHF signal leaks through the basin insulator to the standard external sensor. This process changes the electromagnetic wave polarization mode, resulting in significant attenuation of the UHF signal. The simulated UHF electromagnetic wave also experiences some attenuation when passing through the handhole of the built-in sensor. By taking into account and correcting for these attenuation losses of the UHF electromagnetic wave, the equivalent height of the built-in sensor can be obtained from the equivalent height of the external sensor. Attached Figure Description

[0052] Figure 1 This is a flowchart of the GIS UHF verification process based on the calculation of equivalent height according to an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of GIS UHF verification based on the calculation of equivalent height, according to an embodiment of the present invention. Detailed Implementation

[0054] 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] This embodiment discloses a verification method for a built-in UHF sensor in a GIS device. The method consists of seven steps, as follows: Figure 1 As shown.

[0056] The first step is to measure the frequency domain equivalent height of a standard external sensor. It includes the following specific operations:

[0057] S101: Place the standard external sensor at the opening where the field strength is more concentrated on the rear third of the upper surface of the GTEM chamber;

[0058] S102: Inject a double-exponential ultra-high frequency pulse signal into the GTEM cell;

[0059] S103: The frequency domain equivalent height of the standard external sensor was obtained from the background measurement. .

[0060] The second step involves measuring relevant GIS parameters and calculating the leakage of electromagnetic waves as they pass through the basin insulator. This includes the following specific operations:

[0061] S201: Measure the inner diameter of this GIS a and the radius of the basin insulator at any position r ;

[0062] S202: Substitute into the formula to calculate the frequency domain attenuation of the ultra-high frequency electromagnetic wave when it passes through the basin insulator:

[0063]

[0064] The third step is to calculate the attenuation of the ultra-high frequency electromagnetic wave as it passes through the handhole. This includes the following specific operations:

[0065] S301: Measure the horizontal distance between the lead wire of the built-in sensor to be calibrated and the outer wall of the GIS. d ;

[0066] S302: Substitute into the formula to calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when passing through a hand-hole circular waveguide:

[0067]

[0068] The fourth step is to complete the setup and wiring of the necessary equipment for verification. This includes the following specific operations:

[0069] S401: Place the standard external sensor, calibrated by the GTEM cell, close to the basin insulator that is radially closest to the internal sensor to be calibrated;

[0070] S402: Use the sensor adjacent to the built-in sensor to be calibrated as the injection sensor, and connect the handheld pulse generator to the power supply port of the injection sensor;

[0071] S403: Connect the interfaces of the built-in sensor to be calibrated and the standard external sensor to CH1 (channel 1) and CH2 (channel 2) of the high-speed oscilloscope, respectively;

[0072] S404: The sensor is wrapped in tin foil to prevent the signal from propagating through the outside air and affecting the test results.

[0073] Step 5: Inject a pulse and measure the response voltage of the built-in and standard external sensors under that pulse. This includes the following steps:

[0074] S501: Turn on the handheld pulse generator switch and inject a standard double-exponential voltage pulse of a certain amplitude and frequency into the external sensor adjacent to the built-in sensor to be calibrated. Adjust repeatedly to ensure that the injected voltage pulse can simulate the ultra-high frequency electromagnetic wave signal excited by partial discharge.

[0075] In this embodiment, the pulse signal injected into the 252kV GIS is a voltage signal with an amplitude of 20V and a frequency of 100Hz, with a pulse rise time of approximately 260ps to less than 300ps. The injected pulse signal in other cases is basically similar to that in this example.

[0076] S502: Measures the frequency domain response voltage of the built-in sensor. Response voltage in the frequency domain of a standard external sensor .

[0077] Step 6: Substitute the values ​​into the formula to calculate the frequency domain equivalent height of the built-in sensor:

[0078]

[0079] Step 7: Calculate the mean value of the frequency domain equivalent height of the built-in sensor. and minimum value .like and If the signal is normal, the built-in UHF sensor is functioning correctly. Otherwise, the sensitivity of the built-in UHF sensor will decrease.

[0080] This embodiment innovatively proposes a scheme for verifying UHF built-in sensors based on the calculated equivalent height of the sensor in the frequency domain. Since the pre-installed built-in sensor cannot be removed from the operational GIS, it cannot be placed in the GTEM cell to calculate its equivalent height. Therefore, the equivalent height of the built-in sensor must be indirectly calculated using an external sensor calibrated in the GTEM cell. For example... Figure 2 As shown, a standard external sensor is placed in close proximity to the basin-type insulator adjacent to the built-in sensor to be calibrated. An equivalent artificial pulse is injected into the external sensor adjacent to the built-in sensor to be calibrated. The frequency domain voltages output by the built-in sensor and the standard external sensor can be obtained, and their ratio can be calculated. Simultaneously, the simulated UHF signal leaks through the basin-type insulator to the standard external sensor. During this process, the electromagnetic wave polarization mode changes, resulting in significant attenuation of the UHF signal. The simulated UHF electromagnetic wave also experiences some attenuation when passing through the handhole of the built-in sensor. Taking into account and correcting for these attenuation losses of the UHF electromagnetic wave, the equivalent height of the built-in sensor can be obtained from the equivalent height of the external sensor.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating a GIS UHF built-in sensor based on a calculated equivalent height, characterized in that, Includes the following steps: The first step is to measure the frequency domain equivalent height of a standard external sensor. ; The second step is to measure the inner diameter of the GIS. a and the radius of the basin insulator r Therefore, the frequency domain attenuation of ultra-high frequency electromagnetic waves leaking from the basin insulator can be calculated. The third step is to measure the distance between the UHF built-in sensor at the GIS handhole and the GIS housing. d Calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when they pass through a circular waveguide with a built-in handhole; The fourth step is to complete the connection and wiring of the experimental setup, including placing the standard external sensor close to the basin insulator closest to the built-in sensor to be calibrated, connecting the pulse generator, and connecting the interfaces of the built-in sensor to be calibrated and the standard external sensor to the oscilloscope. Fifth, inject a standard double-exponential voltage pulse of a certain amplitude and frequency into an external sensor adjacent to the built-in sensor to be calibrated, and measure the output voltage of the built-in sensor. and standard external sensor output voltage ; Step 6: Using the measured equivalent height of the standard external sensor and the attenuation characteristics of electromagnetic waves in GIS, the frequency domain equivalent height of the built-in sensor to be calibrated is indirectly calculated. ; Step 7: Calculate the mean value of the frequency domain equivalent height of the built-in sensor. and minimum value According to the mean and minimum value Determine the sensitivity of the UHF built-in sensor.

2. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 1, characterized in that, The first step includes the following specific operations: S101: Place the standard external sensor at the opening where the field strength is more concentrated on the rear third of the upper surface of the GTEM chamber; S102: Inject a double-exponential ultra-high frequency pulse signal into the GTEM cell; S103: The frequency domain equivalent height of the standard external sensor was determined by background measurement. .

3. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 1, characterized in that, The second step includes the following specific operations: S201: Measure the inner diameter of this GIS a and the radius of the basin insulator at any position r ; S202: Substitute into the formula to calculate the frequency domain attenuation of the ultra-high frequency electromagnetic wave when it passes through the basin insulator: 。 4. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 3, characterized in that, The third step includes the following operations: S301: Measure the horizontal distance between the lead wire of the built-in sensor to be calibrated and the outer wall of the GIS. d ; S302: Substitute into the formula to calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when passing through a hand-hole circular waveguide: 。 5. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 1, characterized in that, The fourth step includes the following operations: S401: Place the standard external sensor, calibrated by the GTEM cell, close to the basin insulator that is radially closest to the internal sensor to be calibrated; S402: Use the external sensor adjacent to the built-in sensor to be calibrated as the injection sensor, and connect the handheld pulse generator to the power supply port of the injection sensor; S403: Connect the interfaces of the built-in sensor to be calibrated and the standard external sensor to CH1 and CH2 of the high-speed oscilloscope, respectively; S404: The sensor is wrapped in tin foil to prevent the signal from propagating through the outside air and affecting the test results.

6. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 4, characterized in that, The fifth step includes the following operations: S501: Turn on the handheld pulse generator switch and inject a standard double-exponential voltage pulse of a certain amplitude and frequency into the external sensor adjacent to the built-in sensor to be calibrated; repeatedly adjust to ensure that the injected voltage pulse can simulate the ultra-high frequency electromagnetic wave signal excited by partial discharge; S502: Measures the frequency domain response voltage of the built-in sensor. Response voltage in the frequency domain of a standard external sensor .

7. The verification method for GIS UHF built-in sensors based on calculated equivalent height according to claim 6, characterized in that, The formula for calculating the frequency domain equivalent height of the built-in sensor in step six is ​​as follows: 。 8. A verification system for GIS UHF built-in sensors based on calculated equivalent height, characterized in that, include: The first measurement module is used to measure the frequency domain equivalent height of a standard external sensor. ; The second measurement module is used to measure the inner diameter of the GIS. a and the radius of the basin insulator r Therefore, the frequency domain attenuation of ultra-high frequency electromagnetic waves leaking from the basin insulator can be calculated. The third measurement module is used to measure the distance between the UHF built-in sensor at the GIS handhole and the GIS housing. d Calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when they pass through a circular waveguide with a built-in handhole; The experimental module completes the connection and wiring of the experimental device, including placing the standard external sensor close to the basin insulator closest to the built-in sensor to be calibrated, connecting the pulse generator, and connecting the interfaces of the built-in sensor to be calibrated and the standard external sensor to the oscilloscope. The fourth measurement module is used to inject a standard double-exponential voltage pulse of a certain amplitude and frequency into an external sensor adjacent to the built-in sensor to be calibrated, and to measure the output voltage of the built-in sensor. and standard external sensor output voltage ; The first calculation module indirectly calculates the frequency domain equivalent height of the built-in sensor to be calibrated by using the measured equivalent height of the standard external sensor and the attenuation characteristics of electromagnetic waves in GIS. ; The second calculation module calculates the mean value of the frequency domain equivalent height of the built-in sensor. and minimum value According to the mean and minimum value Determine the sensitivity of the UHF built-in sensor.

9. The verification system for GIS UHF built-in sensors based on calculated equivalent height according to claim 8, characterized in that, The second measurement module includes the following specific operations: S201: Measure the inner diameter of this GIS a and the radius of the basin insulator at any position r ; S202: Substitute into the formula to calculate the frequency domain attenuation of the ultra-high frequency electromagnetic wave when it passes through the basin insulator: 。 10. The verification system for GIS UHF built-in sensors based on calculated equivalent height according to claim 9, characterized in that, The third measurement module includes the following operations: S301: Measure the horizontal distance between the lead wire of the built-in sensor to be calibrated and the outer wall of the GIS. d ; S302: Substitute into the formula to calculate the frequency domain attenuation of ultra-high frequency electromagnetic waves when passing through a hand-hole circular waveguide: 。 11. The verification system for GIS UHF built-in sensors based on calculated equivalent height according to claim 10, characterized in that, The fourth measurement module includes the following operations: S501: Turn on the handheld pulse generator switch and inject a standard double-exponential voltage pulse of a certain amplitude and frequency into the external sensor adjacent to the built-in sensor to be calibrated; repeatedly adjust to ensure that the injected voltage pulse can simulate the ultra-high frequency electromagnetic wave signal excited by partial discharge; S502: Measures the frequency domain response voltage of the built-in sensor. Response voltage in the frequency domain of a standard external sensor .

12. The verification system for GIS UHF built-in sensors based on calculated equivalent height according to claim 11, characterized in that, The formula for calculating the frequency domain equivalent height of the built-in sensor in the first calculation module is as follows: 。

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