Vacuum switch arc extinguish chamber vacuum degree detection device and method based on photomultiplier

Abstract

The invention relates to a device and a method for detecting the vacuum degree of a vacuum switch arc extinguish chamber based on a photomultiplier. The device comprises a plasma excitation module used for exciting a plasma signal in the vacuum switch arc extinguish chamber to be detected; the photomultiplier detection module is used for detecting a plasma signal, acquiring the plasma signal by providing focusing voltage and accelerating voltage, and converting the plasma signal into a current signal; the signal conversion module is used for converting the current signal into a voltage signal; the detection module is used for extracting characteristic parameters from the voltage signals, judging the vacuum degree interval of the arc extinguish chamber of the vacuum switch to be detected, and calculating the vacuum degree of the arc extinguish chamber of the vacuum switch to be detected according to a preset fitting relation curve; and the control module is used for controlling the plasma excitation module to perform excitation and optimizing control on the plasma excitation module according to the calculated vacuum degree result. Compared with the prior art, the method has the advantages of reducing hardware cost and use cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum degree detection, and in particular to a device and method for detecting the vacuum degree of an arc extinguishing chamber of a vacuum switch based on a photomultiplier tube. Background Art

[0002] With the advancement of the "dual carbon" goal, the transformation of the power system to green and low-carbon has become imperative. The continuous advancement of vacuum switch technology makes it possible to replace SF6 switches in power systems at high and ultra-high voltage transmission levels.

[0003] At present, the lack of online monitoring methods for vacuum degree of vacuum switches has greatly limited the large-scale application of 126kV transmission-level vacuum circuit breakers. The vacuum degree detection method of vacuum switches based on laser-induced plasma is expected to achieve online detection of vacuum degree. This method focuses a pulsed laser on the surface of the shield through a convex lens to generate a ball of plasma, and uses instruments such as a spectrometer and an enhanced charge-coupled device (ICCD) to study the spectrum and image of the laser plasma under different vacuum degrees, thereby obtaining the relationship between the laser plasma and the vacuum degree. However, the spectrometer and ICCD instruments used in this method are large in size and heavy in weight, which is not convenient for on-site measurement; in addition, these instruments are expensive, which is not conducive to large-scale promotion, and also limits the large-scale use of vacuum switch circuit breakers in medium-high voltage, ultra-high voltage and above transmission-level power grids. Summary of the invention

[0004] The purpose of the present invention is to provide a non-contact, real-time online detection device and method for detecting the vacuum degree of a vacuum switch arc extinguishing chamber based on a photomultiplier tube.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A vacuum degree detection device for a vacuum switch interrupter based on a photomultiplier tube comprises a plasma excitation module and a photomultiplier tube detection module, a signal conversion module and a control subsystem connected thereto in sequence, wherein the control subsystem comprises a detection module and a control module, and the control subsystem is also connected to the photomultiplier tube detection module.

[0007] Plasma excitation module: used to excite plasma signals in the arc extinguishing chamber of the vacuum switch to be tested;

[0008] Photomultiplier tube detection module: used to detect the plasma signal, collect the plasma signal by providing focusing voltage and accelerating voltage, and then convert the plasma signal into a current signal;

[0009] Signal conversion module: used for converting the current signal into a voltage signal;

[0010] Detection module: used to extract characteristic parameters from the voltage signal, determine the vacuum degree range of the vacuum interrupter to be measured, and calculate the vacuum degree of the vacuum interrupter to be measured according to the preset fitting relationship curve;

[0011] Control module: used to control the plasma excitation module to perform excitation and optimize the control of the plasma excitation module according to the calculated vacuum degree result.

[0012] Further, the plasma excitation module includes an excitation unit, a generation unit and a dichroic mirror,

[0013] The excitation unit includes a laser, a laser mirror, a large bandwidth mirror, a focusing lens and a dichroic mirror arranged in sequence. The laser emits a laser beam, and the laser mirror and the large bandwidth mirror adjust the optical path direction of the laser beam. Then, the laser beam is focused on the generation unit through the focusing lens and the dichroic mirror;

[0014] The generation unit includes a window and a T2 copper plate arranged inside the vacuum interrupter of the vacuum switch. The window is opened on the vacuum interrupter of the vacuum switch and is arranged opposite to the position of the focusing lens. The window is used for the intake of the laser beam and the emission of the plasma signal. The T2 copper plate is used for the focused laser beam to strike its surface to excite the plasma signal, and the plasma signal is separated and transmitted to the photomultiplier tube detection module through the dichroic mirror.

[0015] Further, the excitation unit further includes a high-precision stepping platform, and the focusing lens is arranged on the high-precision stepping platform. The high-precision stepping platform is used to assist the focusing lens to focus the laser beam.

[0016] Further, the photomultiplier tube detection module includes a photomultiplier tube unit and a high-voltage power supply unit connected thereto,

[0017] The photomultiplier tube unit: used to detect the plasma signal and convert the plasma signal into a current signal;

[0018] The high-voltage power supply unit: used to provide a focusing voltage and an accelerating voltage.

[0019] Further, the signal conversion module includes a current feedback type amplifier and a high-speed analog-to-digital converter,

[0020] The current feedback type amplifier: used to convert the current signal into a voltage signal;

[0021] The high-speed analog-to-digital converter: used to collect and digitize the voltage signal.

[0022] Further, the detection module includes a characteristic parameter extraction unit, a characteristic parameter determination unit and a vacuum degree calculation unit,

[0023] The feature parameter extraction unit: is used to extract feature parameters from the voltage signal;

[0024] The feature parameter determination unit: is used to determine the vacuum degree range of the vacuum switch to be measured according to the feature parameters, where different vacuum degree ranges correspond to different preset fitting relationship curves;

[0025] The vacuum degree calculation unit: is used to input the feature parameters into the corresponding preset fitting relationship curve to obtain the vacuum degree of the vacuum switch to be measured.

[0026] Further, the feature parameters include the peak value of the voltage signal and the voltage signal value at a specified time point.

[0027] Further, the corresponding relationship between the different vacuum degree ranges and the different preset fitting relationship curves is:

[0028] When the vacuum degree is less than 3×10 -1 Pa, the preset fitting relationship curve is:

[0029] y = -811.95638x 3 +1411.65359x 2 -818.3283x + 158.19366

[0030] When the vacuum degree is greater than 3×10 -1 Pa, the preset fitting relationship curve is:

[0031] y = 12.75231x 2 +3.31639x - 4.6689y = 12.75231x 2 +3.31639x - 4.6689

[0032] In the formula, y is the vacuum degree and x is the peak value of the voltage signal.

[0033] Further, the control module includes a laser control unit and a feedback adjustment unit,

[0034] The laser control unit: is connected to the laser, and the laser control unit is used to control the pulse frequency, energy and working state of the laser;

[0035] The feedback adjustment unit: is respectively connected to the laser and the detection module, and the feedback adjustment unit is used to adjust the excitation parameters of the laser according to the vacuum degree result.

[0036] The present invention also provides a detection method for a vacuum switch arc extinguishing chamber vacuum degree detection device based on a photomultiplier tube as described above, including the following steps:

[0037] Signal excitation: The laser control unit controls the laser to emit a laser beam, which is directed onto the T2 copper plate via a laser mirror, a large-bandwidth mirror, a focusing lens, and a dichroic mirror to generate a plasma signal in the arc extinguishing chamber of the vacuum switch to be measured;

[0038] Signal collection: The photomultiplier unit detects the plasma signal. Meanwhile, the high-voltage power supply unit provides a focusing voltage and an accelerating voltage to collect the plasma signal, and the photomultiplier unit then converts the plasma signal into a current signal;

[0039] Signal processing: A current feedback amplifier converts the current signal into a voltage signal, and a high-speed analog-to-digital converter collects and digitalizes the voltage signal;

[0040] Vacuum degree calculation: The characteristic parameter extraction unit extracts characteristic parameters from the voltage signal. The characteristic parameter determination unit determines the vacuum degree range of the arc extinguishing chamber of the vacuum switch to be measured according to the characteristic parameters. The vacuum degree calculation unit inputs the characteristic parameters into the corresponding preset fitting relationship curve to obtain the vacuum degree of the arc extinguishing chamber of the vacuum switch to be measured, where different vacuum degree ranges correspond to different preset fitting relationship curves;

[0041] Detection result feedback: The feedback adjustment unit obtains the vacuum degree result calculated by the vacuum degree calculation unit and adjusts the excitation parameters of the laser according to the vacuum degree result.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The present invention excites a plasma signal in the arc extinguishing chamber of the vacuum switch to be measured. The photomultiplier detection module detects the plasma signal and converts it into an electrical signal. The vacuum degree is calculated according to the characteristic parameters of the electrical signal and the preset fitting relationship curve, realizing non-contact and real-time online detection.

[0044] (2) The present invention uses a photomultiplier detection module to detect the plasma signal. Compared with a spectrometer or an ICCD device, the cost of this module is lower or even negligible, greatly reducing the cost of vacuum switch vacuum degree detection; the photomultiplier has a smaller volume. Compared with a spectrometer or an ICCD device, it has the advantages of a smaller volume and a lighter weight, and is more suitable as a vacuum degree detection device used in actual engineering.

[0045] (3) The present invention uses a photomultiplier as the detection device for the plasma, reducing the hardware cost and usage cost of the vacuum degree detection technology based on laser-induced plasma, facilitating the popularization of this technology, reducing the maintenance cost of power equipment, promoting the replacement of SF6 switches by vacuum switch equipment in power systems at high-voltage and extra-high-voltage transmission levels, and promoting the development of the power system towards the direction of green and low-carbon.

[0046] (4) In the plasma excitation module of the present invention, the laser mirror and the broadband mirror are used to adjust the direction of the laser optical path to ensure that the laser is vertically focused on the center of the T2 copper plate. The focusing lens focuses the laser energy onto the surface of the T2 copper plate to enhance the plasma excitation efficiency. The dichroic mirror separates the optical paths of the laser beam and the plasma signal, enabling the incident optical path of the laser beam and the emission optical path of the plasma signal to coexist simultaneously without interference, providing a good basis for vacuum degree detection.

[0047] (5) The control module of the present invention optimizes the parameters of the laser based on the vacuum degree detection result, which can improve the detection accuracy of the next detection device and enable continuous long-term online monitoring. Description of the Drawings

[0048] Figure 1 It is a schematic structural diagram of the device of the present invention. Detailed Embodiments

[0049] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0050] Embodiment 1

[0051] This embodiment provides a vacuum degree detection device for a vacuum switch arc extinguishing chamber based on a photomultiplier tube. As Figure 1 shown, the device includes a plasma excitation module and a photomultiplier tube detection module 7, a signal conversion module 8, and a control subsystem 9 that are sequentially connected thereto. The control subsystem 9 includes a detection module and a control module, and the control subsystem 9 is also connected to the photomultiplier tube detection module 7.

[0052] The plasma excitation module includes an excitation unit, a generation unit, and a dichroic mirror 6. The excitation unit includes a laser 1, a laser mirror 2, a broadband mirror 3, a high-precision stepping stage 4, a focusing lens 5, and a dichroic mirror 6 that are sequentially arranged. The generation unit includes a window 12 and a vacuum switch target material disposed inside the vacuum switch arc extinguishing chamber 10 to be measured. The target material is a T2 copper plate 11. The window 12 is disposed on the vacuum switch arc extinguishing chamber 10 to be measured and is disposed opposite to the focusing lens 5 in position.

[0053] The working principle of this plasma excitation module is as follows:

[0054] The laser 1 emits a nanosecond pulsed laser beam. The laser mirror 2 and the wide-bandwidth mirror 3 adjust the optical path direction of the laser beam to ensure that the laser is vertically focused on the center of the T2 copper plate 11. The focusing lens 5 enhances the plasma excitation efficiency by focusing the laser beam energy through the window 12 onto the surface of the T2 copper plate 11. The high-precision stepper stage 4 is arranged below the focusing lens 5 and is used to precisely adjust the laser beam focusing position. The dichroic mirror 6 is used to separate the optical paths of the laser beam and the plasma signal, ensuring that the photomultiplier detection module 7 receives only the plasma optical signal.

[0055] The photomultiplier detection module 7 includes a photomultiplier unit and a high-voltage power supply unit connected thereto. The photomultiplier unit is used to detect and collect the plasma signal, convert the plasma signal into a high-sensitivity current signal. The photomultiplier unit has a response time less than 2.2 ns and a spectral response range from 185 nm to 870 nm. The high-voltage power supply unit is used to provide a focusing voltage and an accelerating voltage.

[0056] The signal conversion module 8 includes a current-feedback amplifier and a high-speed analog-to-digital converter. The current-feedback amplifier is used to convert the current signal output by the photomultiplier detection module 7 into a voltage signal, with an amplification bandwidth not less than 5500 V / μs. The high-speed analog-to-digital converter is used to collect and digitize the voltage signal, with a resolution not less than 8 bit and a sampling frequency not less than 100 MSPS.

[0057] The detection module includes a characteristic parameter extraction unit, a characteristic parameter determination unit, and a vacuum degree calculation unit. The characteristic parameter extraction unit is used to extract the peak value of the voltage signal and the voltage signal value at a specified time point. The characteristic parameter determination unit is used to determine the vacuum degree interval of the arc-extinguishing chamber 10 of the vacuum switch to be measured according to the characteristic parameters. The vacuum degree calculation unit is used to calculate the specific vacuum degree of the arc-extinguishing chamber 10 of the vacuum switch to be measured based on the characteristic parameters through a fitting relationship curve.

[0058] In this embodiment, the first characteristic parameter of the voltage signal is the signal peak value, and the second characteristic parameter is the voltage signal value at 14 μs. When the voltage signal peak value is lower than 0.042225 V, it is determined that the vacuum degree is greater than 3×10 -1 Pa; according to the preset fitting relationship curve, the vacuum degree in different intervals is calculated.

[0059] When the vacuum degree is less than 3×10 -1 Pa, the fitting relationship between the voltage peak signal and the vacuum degree is:

[0060] y = -811.95638x3 + 1411.65359x2 - 818.3283x + 158.19366;

[0061] When the vacuum degree is greater than 3×10-1 Pa, the fitting relationship between the voltage peak signal and the vacuum degree is:

[0062] y = 12.75231x 2 +3.31639x - 4.6689y = 12.75231x 2 +3.31639x - 4.6689,

[0063] wherein, x is the peak value of the output voltage / V, and y is the vacuum degree / Pa.

[0064] The control module includes a laser control unit and a feedback adjustment unit. The laser control unit is connected to the laser 1 and is used to control the pulse frequency, energy, and working state of the laser 1. The feedback adjustment unit is used to adjust the excitation parameters of the laser 1 according to the detection results to optimize the detection accuracy.

[0065] The detection method of the above detection device includes the following steps:

[0066] Excitation signal: The laser control unit sets the emission parameters of the laser 1, and the laser 1 generates a plasma signal by emitting a laser beam to excite the vacuum switch target material.

[0067] Signal collection: The photomultiplier tube detection module 7 is used to detect and collect the plasma signal and convert it into a current signal.

[0068] Signal processing: The signal conversion module 8 is used to convert the current signal into a voltage signal.

[0069] Vacuum degree calculation: The detection module extracts the characteristic parameters, determines the vacuum degree range of the arc extinguishing chamber 10 of the vacuum switch to be measured, and inputs the corresponding preset fitting relationship curve to obtain the vacuum degree of the arc extinguishing chamber 10 of the vacuum switch to be measured.

[0070] Detection result feedback: The vacuum degree result is output, and the excitation parameters of the laser 1 are optimized according to the detection results.

[0071] Embodiment 2

[0072] This embodiment provides a vacuum degree detection device for the arc extinguishing chamber of a vacuum switch based on a photomultiplier tube. Different from Embodiment 1, the high-speed analog-to-digital converter is replaced by a signal acquisition board.

[0073] The rest is the same as in Embodiment 1.

[0074] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0075] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A vacuum degree detection device for a vacuum switch interrupter based on a photomultiplier tube, characterized in that: The invention comprises a plasma excitation module and a photomultiplier tube detection module (7) connected thereto in sequence, a signal conversion module and a control subsystem (9), wherein the control subsystem (9) comprises a detection module and a control module, and the control subsystem (9) is also connected to the photomultiplier tube detection module (7). Plasma excitation module: used for exciting a plasma signal in the arc extinguishing chamber (10) of the vacuum switch to be tested; A photomultiplier tube detection module (7): used to detect the plasma signal, collect the plasma signal by providing a focusing voltage and an accelerating voltage, and then convert the plasma signal into a current signal; A signal conversion module (8): used for converting the current signal into a voltage signal; A detection module is used to extract characteristic parameters from the voltage signal, determine the vacuum degree interval of the arc extinguishing chamber (10) of the vacuum switch to be tested, and calculate the vacuum degree of the arc extinguishing chamber (10) of the vacuum switch to be tested according to a preset fitting relationship curve; Control module: used to control the plasma excitation module to excite and optimize the control of the plasma excitation module according to the calculated vacuum degree result.

2. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 1, characterized in that: The plasma excitation module comprises an excitation unit, a generation unit and a dichroic mirror (6), The excitation unit comprises a laser (1), a laser reflector (2), a wide bandwidth reflector (3), a focusing lens (5) and a dichroic mirror (6) which are arranged in sequence. The laser (1) emits a laser beam, the laser reflector (2) and the wide bandwidth reflector (3) adjust the optical path direction of the laser beam, and then the laser beam is focused on the generation unit via the focusing lens (5) and the dichroic mirror (6); The generating unit comprises a window (12) and a T2 copper plate (11) arranged inside a vacuum switch arc extinguishing chamber (10); the window (12) is opened on the vacuum switch arc extinguishing chamber (10) and is arranged relative to a focusing lens (5); the window (12) is used for receiving a laser beam and emitting a plasma signal; the T2 copper plate (11) is used for the focused laser beam to strike its surface to excite a plasma signal; the plasma signal is separated and transmitted to a photomultiplier tube detection module (7) via a dichroic mirror (6).

3. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 2, characterized in that: The excitation unit further comprises a high-precision stepping stage (4), the focusing lens (5) is arranged on the high-precision stepping stage (4), and the high-precision stepping stage (4) is used to assist the focusing lens (5) in focusing the laser beam.

4. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 1, characterized in that: The photomultiplier tube detection module (7) comprises a photomultiplier tube unit and a high-voltage power supply unit connected thereto. The photomultiplier tube unit is used to detect the plasma signal and convert the plasma signal into a current signal; The high voltage power supply unit is used to provide focusing voltage and accelerating voltage.

5. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 1, characterized in that: The signal conversion module (8) comprises a current feedback amplifier and a high-speed analog-to-digital converter, The current feedback amplifier is used to convert the current signal into a voltage signal; The high speed analog-to-digital converter: Used to collect and digitize the voltage signal.

6. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 1, characterized in that: The detection module includes a characteristic parameter extraction unit, a characteristic parameter determination unit and a vacuum degree calculation unit. The characteristic parameter extraction unit is used to extract the characteristic parameter from the voltage signal; The characteristic parameter determination unit is used to determine the vacuum degree interval of the vacuum switch to be tested according to the characteristic parameter, wherein different vacuum degree intervals correspond to different preset fitting relationship curves; The vacuum degree calculation unit is used to input the characteristic parameter into the corresponding preset fitting relationship curve to obtain the vacuum degree of the vacuum switch to be tested.

7. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 6, characterized in that: The characteristic parameters include the peak value of the voltage signal and the voltage signal value at a specified time point.

8. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 6, characterized in that: The corresponding relationship between the different vacuum degree intervals and the different preset fitting relationship curves is: Vacuum degree is less than 3×10 -1 When Pa, the preset fitting relationship curve is: <h2 style=";text-align:left;direction:ltr">y=-811.95638x<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> +1411.65359x<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> -818.3283x+158.19366 Vacuum degree greater than 3×10 -1 When Pa, the preset fitting relationship curve is: <h2 style=";text-align:left;direction:ltr">y = 12.75231x<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +3.31639x-4.6689y = 12.75231x<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +3.31639x-4.6689 Where y is the vacuum degree and x is the peak value of the voltage signal.

9. The device for detecting vacuum degree of vacuum switch interrupter based on photomultiplier tube according to claim 2, characterized in that: The control module includes a laser control unit and a feedback adjustment unit. The laser control unit is connected to the laser (1), and is used to control the pulse frequency, energy and working state of the laser (1); The feedback adjustment unit is connected to the laser (1) and the detection module respectively, and is used to adjust the excitation parameters of the laser (1) according to the vacuum degree result.

10. A detection method for a vacuum degree detection device for a vacuum switch interrupter based on a photomultiplier tube according to any one of claims 1 to 9, characterized in that: The following steps are involved: Signal excitation: the laser control unit controls the laser (1) to emit a laser beam, and the laser beam is struck on a T2 copper plate (11) via a laser reflector (2), a wide bandwidth reflector (3), a focusing lens (5) and a dichroic mirror (6), so as to generate a plasma signal in the arc extinguishing chamber (10) of the vacuum switch to be tested; Signal collection: the photomultiplier tube unit detects the plasma signal, and the high-voltage power supply unit provides focusing voltage and acceleration voltage to collect the plasma signal, and the photomultiplier tube unit then converts the plasma signal into a current signal; Signal processing; The current feedback amplifier converts the current signal into a voltage signal, and the high-speed analog-to-digital converter collects and digitizes the voltage signal; Vacuum degree calculation: the characteristic parameter extraction unit extracts characteristic parameters from the voltage signal, the characteristic parameter determination unit determines the vacuum degree interval of the arc extinguishing chamber (10) of the vacuum switch to be tested according to the characteristic parameters, the vacuum degree calculation unit inputs the characteristic parameters into a corresponding preset fitting relationship curve to obtain the vacuum degree of the arc extinguishing chamber (10) of the vacuum switch to be tested, wherein different vacuum degree intervals correspond to different preset fitting relationship curves; Feedback of detection results: the feedback adjustment unit obtains the vacuum degree result calculated by the vacuum degree calculation unit, and adjusts the excitation parameters of the laser (1) according to the vacuum degree result.

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