1. The utility model provides a test observation device of transient state gas discharge in semi-closed microcavity which characterized in that: the test observation device for transient gas discharge in the semi-closed microcavity comprises an impulse current generator, a core-through current transformer, a capacitive voltage divider, a digital storage oscilloscope, a synchronous trigger, a high-speed camera and a data processor;

the negative pole of the impulse current generator is grounded by taking a woven copper strip as a connecting wire, the current output end of the impulse current generator is connected with the high-voltage end of the test sample semi-closed micro-cavity device through a pulse ignition ball gap, and a capacitive voltage divider is connected on the connecting wire of the pulse ignition ball gap and the test sample semi-closed micro-cavity device; the low-voltage end of the test sample semi-closed micro-cavity device is connected with the grounding end of the capacitive voltage divider while penetrating through the core-penetrating current transformer by using a braided copper strip as a connecting wire and then being grounded;

the high-speed camera at least comprises a high-speed camera capable of shooting an integral image of the electric arc and a high-speed camera capable of shooting a local image of the electric arc, the high-speed cameras are respectively connected with the data processor and the synchronous trigger through signal lines, the synchronous trigger is connected with an output channel of the digital storage oscilloscope, and an input channel of the digital storage oscilloscope is respectively connected with the capacitive voltage divider and the feedthrough current transformer.

2. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the impulse current generator comprises an intelligent control system, a voltage regulator T1, a boosting transformer T2, a silicon stack D, a wave regulating resistor R, a wave regulating inductor L, a pulse capacitor bank C and a pulse ignition ball gap, wherein the wire inlet end of the voltage regulator T1 is connected with a 380V power frequency power supply through a wire, the wire outlet end of the voltage regulator T1 is connected with the primary side of the boosting transformer T2 through a wire, the secondary side of the boosting transformer T2 is connected with the silicon stack D through a wire, and the pulse capacitor bank C is charged through rectification of the silicon stack D.

3. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the impulse current generator can generate double-exponential current waves with adjustable amplitude of 8-200 kA, variable wave front time of 1.2-20 mu s and variable wave tail time of 20-1000 mu s, and the pulse ignition spherical gap applies ignition pulses through the pulse ignition device to perform breakdown discharge.

4. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the core-through current sensor and the digital storage oscilloscope form a current measuring system; the core-penetrating current transformer consists of a non-magnetic framework, a copper coil, an integrating circuit, a bayonet nut connector socket and a polymer insulation shell; the non-magnetic conducting framework is a circular ring which is made of a non-magnetic conducting polymer, and has the inner diameter of 2-10 cm, the outer diameter of 2.5-12 cm and the cross-section diameter of 1-4 cm.

5. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the capacitive voltage divider and the digital storage oscilloscope form a voltage measuring system; the voltage division ratio is 1000:1, the measurement amplitude is-400 kV, and the frequency is 0-1 MHz.

6. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the digital storage oscilloscope is powered by an independent power supply, can simultaneously acquire voltage signals with amplitude of-400V and frequency of 0-100 MHz in 2 signal acquisition channels, and has sampling frequency of 0-10 GS/s and storage capacity of 0-100 MB.

7. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the high-speed cameras are connected with the synchronous trigger through signal lines, the high-speed cameras are two high-speed cameras which are vertically arranged at the same position, or the two high-speed cameras are symmetrically arranged by taking the test sample semi-closed micro-cavity device as a midpoint.

8. The experimental observation apparatus of transient gas discharge in semi-closed microcavity according to claim 1, wherein: the high-speed cameras are connected with the synchronous trigger through signal lines, and the high-speed cameras are a plurality of high-speed cameras which are arranged on an arc with the semi-closed micro-cavity device of the test sample as the circle center at equal central angles.

9. A method for testing and observing gas discharge in a semi-closed microcavity, which adopts the device for testing and observing transient gas discharge in a semi-closed microcavity as claimed in any one of claims 1-8, and is characterized in that: the test observation method for gas discharge in the semi-closed micro-cavity comprises the following shooting steps:

determining test loop element parameters: dividing the wave head time and the wave tail time of the actual lightning current by a simulation proportion n, calculating the wave head time and the wave tail time of the impact current of a simulation test, and changing the sizes of a wave regulating resistor R and a wave regulating inductor L in a loop of an impact current generator to achieve the calculated wave head time and the calculated wave tail time of the impact current;

checking whether the impulse current waveform meets the requirements: connecting two ends of a semi-closed microcavity device of a test sample in a short circuit mode, starting an impact current generator to output impact current under the short circuit condition, and judging whether the current waveform meets the requirement or not through the waveform displayed by a digital storage oscilloscope;

determining the placing position of the high-speed camera and adjusting shooting parameters: the method comprises the steps that two high-speed cameras are oppositely placed, the placing height is the same as the height of a test sample semi-closed micro-cavity device, the focal length of the camera for shooting an electric arc overall image is adjusted until a data processor displays a clear image, a long-focus lens is additionally arranged on the camera for shooting a local image, focusing is carried out until the data processor displays the clear image of the local position, the positions of the high-speed cameras and the test sample semi-closed micro-cavity device are fixed, the frame rate is 2500fps, a trigger mode is set as parameters required by central point triggering and ISO light sensitivity through data processor control software, and the frame rate and the trigger mode of the two high-speed cameras are guaranteed to be the same;

the test was started: and removing short circuit connection wires at two ends of the test sample semi-closed micro-cavity device, setting a charging voltage value of the impact current generator, starting charging after setting charging time according to the impact voltage value, triggering the impact current generator after charging is finished, simultaneously sending a trigger signal to the high-speed camera to shoot an arc image by the synchronous trigger, adjusting the frame rate of control software of the data processor according to the shot image condition, and repeatedly testing for many times.

10. The experimental observation method of gas discharge in a semi-closed microcavity according to claim 9, wherein: the digital storage oscilloscope is used as a trigger signal source for synchronous shooting of the high-speed cameras, when an air gap in a semi-closed microcavity of the test sample semi-closed microcavity device is broken down, the digital storage oscilloscope sends a trigger signal to the synchronous trigger at the same moment, and the synchronous trigger simultaneously sends a plurality of signals to trigger the high-speed cameras, so that the high-speed cameras are synchronously started to shoot.

Background

The semi-closed micro-cavity device is applied to quenching of electric arcs generated by a lightning stroke line of the power transmission line, and reduces power equipment faults caused by the lightning stroke. Quenching tests of the arc in semi-closed microcavities are often performed in laboratories to study the dissipation characteristics of the arc. The observation of the discharge area, the arc development and the dissipation process is the most important part in the test process, however, in the actual test, the tester mainly depends on the visual inspection of the arc generation to the dissipation process, and because the air gap discharge is usually in the microsecond level, the tester cannot capture the arc shape at a certain transient in the discharge process only by naked eyes. Most of current semi-closed microcavity device designs into multi-chamber structure, and the cavity is more, and the quantity reaches dozens to two hundred inequality, and there is the inhomogeneous asymmetry of electric arc development during the quenching electric arc, and there is time delay in different cavity quenching electric arcs, and traditional single high-speed camera can't realize multi-direction, the whole and specific area's of multi-angle electric arc shooting, and the electric arc image is shot to many edgeways in the actual test, is unfavorable for the analysis and the research of multi-chamber structure arc extinguishing process.

In view of the foregoing problems, wuhan university provides a method for shooting an arc path using a single-lens reflex view camera instead of visual observation by human eyes, but in this method, the whole process of arc generation and dissipation cannot be shot at high speed due to insufficient performance of the camera, shooting time needs to be manually set before shooting, and the shooting time interval is long each time, so that the instant shooting of arc occurrence cannot be started. The Qinghua university adopts a mirror image method to shoot a discharge path of an air gap by using a high-speed camera, the distance from the camera to a virtual image in a mirror surface is twice of that of an actual electric arc in the method, so that the image is reduced, the actually shot electric arc mirror image is fuzzy, and the arc form details cannot be observed because the virtual images in two mirror surfaces must be shot simultaneously, so that the arc partial shooting cannot be realized.

Disclosure of Invention

The invention mainly aims to solve the problem that synchronous shooting cannot be realized by presetting shooting time and then applying voltage to generate electric arcs in a semi-closed micro-cavity gas discharge test; and when shooting the multi-cavity arc blow-out image, the problem that only a large-range whole image can be shot and the development and dissipation process of the arc form cannot be shot and observed locally in a specific area is solved, and therefore the device and the method for testing and observing the transient gas discharge in the semi-closed micro-cavity have the advantages of simple shooting process, high imaging efficiency, more accurate image feature extraction and local arc image shooting.

The technical scheme adopted by the invention is as follows:

a test observation device for transient gas discharge in a semi-closed microcavity comprises an impulse current generator, a core-through current transformer, a capacitive voltage divider, a digital storage oscilloscope, a synchronous trigger, a high-speed camera and a data processor;

the negative pole of the impulse current generator is grounded by taking a woven copper strip as a connecting wire, the current output end of the impulse current generator is connected with the high-voltage end of the test sample semi-closed micro-cavity device through a pulse ignition ball gap, and a capacitive voltage divider is connected on the connecting wire of the pulse ignition ball gap and the test sample semi-closed micro-cavity device; the low-voltage end of the test sample semi-closed micro-cavity device is connected with the grounding end of the capacitive voltage divider while penetrating through the core-penetrating current transformer by using a braided copper strip as a connecting wire and then being grounded;

the high-speed camera at least comprises a high-speed camera capable of shooting an integral image of the electric arc and a high-speed camera capable of shooting a local image of the electric arc, the high-speed cameras are respectively connected with the data processor and the synchronous trigger through signal lines, the synchronous trigger is connected with an output channel of the digital storage oscilloscope, and an input channel of the digital storage oscilloscope is respectively connected with the capacitive voltage divider and the feedthrough current transformer.

Preferably, the impulse current generator comprises an intelligent control system, a voltage regulator T1, a step-up transformer T2, a silicon stack D, a wave-modulating resistor R, a wave-modulating inductor L, a pulse capacitor bank C and a pulse ignition ball gap, wherein a wire inlet end of the voltage regulator T1 is connected with a 380V power frequency power supply through a wire, a wire outlet end of the voltage regulator T1 is connected with a primary side of the step-up transformer T2 through a wire, a secondary side of the step-up transformer T2 is connected with the silicon stack D through a wire, and the pulse capacitor bank C is charged through rectification by the silicon stack D.

Preferably, the impulse current generator can generate double-exponential current waves with adjustable amplitude of 8-200 kA, variable wave front time of 1.2-20 mus and variable wave tail time of 20-1000 mus, and the pulse ignition spherical gap applies ignition pulses through the pulse ignition device to perform breakdown discharge.

Preferably, the core-through current sensor and the digital storage oscilloscope form a current measuring system; the core-penetrating current transformer consists of a non-magnetic framework, a copper coil, an integrating circuit, a bayonet nut connector socket and a polymer insulation shell; the non-magnetic conducting framework is a circular ring which is made of a non-magnetic conducting polymer, and has the inner diameter of 2-10 cm, the outer diameter of 2.5-12 cm and the cross-section diameter of 1-4 cm.

Preferably, the capacitive voltage divider and the digital storage oscilloscope form a voltage measuring system; the voltage division ratio is 1000:1, the measurement amplitude is-400 kV, and the frequency is 0-1 MHz.

Preferably, the digital storage oscilloscope is powered by an independent power supply, can simultaneously acquire voltage signals with amplitude of-400V and frequency of 0-100 MHz in 2 signal acquisition channels, and has sampling frequency of 0-10 GS/s and storage capacity of 0-100 MB.

Preferably, the high-speed cameras are connected with the synchronous trigger through signal lines, the two high-speed cameras are vertically arranged at the same position, or the two high-speed cameras are symmetrically arranged by taking the test sample semi-closed micro-cavity device as a midpoint.

Preferably, the high-speed cameras are all connected with the synchronous trigger through signal lines, and the high-speed cameras are a plurality of high-speed cameras which are arranged on an arc with the test sample semi-closed micro-cavity device as the center of a circle at equal central angles.

A method for testing and observing gas discharge in a semi-closed microcavity adopts the device for testing and observing transient gas discharge in the semi-closed microcavity, and comprises the following shooting steps:

determining test loop element parameters: dividing the wave head time and the wave tail time of the actual lightning current by a simulation proportion n, calculating the wave head time and the wave tail time of the impact current of a simulation test, and changing the sizes of a wave regulating resistor R and a wave regulating inductor L in a loop of an impact current generator to achieve the calculated wave head time and the calculated wave tail time of the impact current;

checking whether the impulse current waveform meets the requirements: connecting two ends of a semi-closed microcavity device of a test sample in a short circuit mode, starting an impact current generator to output impact current under the short circuit condition, and judging whether the current waveform meets the requirement or not through the waveform displayed by a digital storage oscilloscope;

determining the placing position of the high-speed camera and adjusting shooting parameters: the method comprises the steps that two high-speed cameras are oppositely placed, the placing height is the same as the height of a test sample semi-closed micro-cavity device, the focal length of the camera for shooting an electric arc overall image is adjusted until a data processor displays a clear image, a long-focus lens is additionally arranged on the camera for shooting a local image, focusing is carried out until the data processor displays the clear image of the local position, the positions of the high-speed cameras and the test sample semi-closed micro-cavity device are fixed, the frame rate is 2500fps, a trigger mode is set as parameters required by central point triggering and ISO light sensitivity through data processor control software, and the frame rate and the trigger mode of the two high-speed cameras are guaranteed to be the same;

the test was started: and removing short circuit connection wires at two ends of the test sample semi-closed micro-cavity device, setting a charging voltage value of the impact current generator, starting charging after setting charging time according to the impact voltage value, triggering the impact current generator after charging is finished, simultaneously sending a trigger signal to the high-speed camera to shoot an arc image by the synchronous trigger, adjusting the frame rate of control software of the data processor according to the shot image condition, and repeatedly testing for many times.

Preferably, the digital storage oscilloscope is used as a trigger signal source for synchronous shooting of the high-speed cameras, when an air gap in a semi-closed microcavity of the test sample semi-closed microcavity device is broken down, the digital storage oscilloscope sends a trigger signal to the synchronous trigger at the same moment, and the synchronous trigger simultaneously sends a plurality of signals to trigger the plurality of high-speed cameras, so that the high-speed cameras synchronously start shooting.

The invention has the beneficial effects that:

1. the capacity of the impulse current generator in the test observation device for transient gas discharge in the semi-closed micro-cavity is very large, so that the impulse current with very high amplitude can be generated in a simulation test, the process that the semi-dense micro-cavity of the test sample semi-closed micro-cavity device quenches electric arcs when actual lightning strikes a circuit can be accurately simulated, and the reliability of a simulation test result is greatly improved.

2. The test observation device for transient gas discharge in the semi-closed micro-cavity utilizes more than two high-speed cameras to synchronously shoot whole and local images of the electric arc, and the local images can be used as supplement of the whole images to pertinently observe the development process and morphological characteristics of the electric arc in a certain area.

3. The digital storage oscilloscope of the test observation device for transient gas discharge in the semi-closed microcavity adopts an independent lithium battery and inverter combination or an off-line UPS power supply to supply power, so that the phenomenon that the potential of a laboratory earth screen rises sharply to damage measuring equipment such as the digital storage oscilloscope, a core-through current transformer and the like when the impact current generator discharges can be effectively prevented.

4. The method for testing and observing gas discharge in the semi-closed micro-cavity has the advantages of simplicity, simplicity and convenience in operation, capability of conveniently adjusting test parameters and the like. In addition, the safety of the simulation test is good, and the accuracy and the reliability of the simulation test result are high.

Drawings

FIG. 1 is a schematic diagram of the connection relationship of the present invention;

FIG. 2 is a schematic diagram of the circuit of the present invention;

FIG. 3 is an overall image of the transient arc development to dissipation process captured using the present invention;

FIG. 4 is a partial image of an instantaneous arc taken using the present invention;

in the figure 1, 1-impulse current generator, 2-pulse ignition ball gap, 3-capacitive voltage divider, 4-core-penetrating current transformer, 5-digital storage oscilloscope, 6-synchronous trigger, 7-high speed camera, 8-data processor, 9-semi-closed micro-cavity device of test sample.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

As shown in fig. 1-2, the present invention provides a device for testing and observing transient gas discharge in a semi-closed microcavity, which comprises a rush current generator 1, a feedthrough current transformer 4, a capacitive voltage divider 3, a digital storage oscilloscope 5, a synchronous trigger 6, a high-speed camera 7 and a data processor 8. The negative pole of the impulse current generator 1 is grounded by taking a woven copper strip as a connecting wire, the current output end of the impulse current generator is connected with the high-voltage end of the test sample semi-closed micro-cavity device 9 through a pulse ignition ball gap 2, and a capacitive voltage divider 3 is connected on the connecting wire of the pulse ignition ball gap 2 and the test sample semi-closed micro-cavity device 9; the low-voltage end of the test sample semi-closed micro-cavity device 9 is connected with the grounding end of the capacitive voltage divider 3 while passing through the core-through current transformer 4 by using a woven copper strip as a connecting wire and then being grounded. The high-speed camera 7 at least comprises a high-speed camera 7 capable of shooting an integral image of the electric arc and a high-speed camera 7 capable of shooting a local image of the electric arc, the high-speed camera 7 is respectively connected with the data processor 8 and the synchronous trigger 6 through signal lines, the synchronous trigger 6 is connected with an output channel of the digital storage oscilloscope 5, and an input channel of the digital storage oscilloscope 5 is respectively connected with the capacitive voltage divider 3 and the feed-through current transformer 4.

The Impulse Current Generator 1 (ICG) is capable of generating a bi-exponential Current wave with an adjustable amplitude of 8-200 kA, a variable wavefront time of 1.2-20 μ s and a variable wave tail time of 20-1000 μ s, and the pulse ignition spherical gap 2 applies an ignition pulse through a pulse ignition device to perform breakdown discharge. The impulse current generator 1 comprises an intelligent control system, a voltage regulator T1, a boosting transformer T2, a silicon stack D, a wave modulation resistor R, a wave modulation inductor L, a pulse capacitor bank C and a pulse ignition ball gap 2. In the test, a 380V alternating current power supply is boosted, the wire inlet end of a voltage regulator T1 is connected with a 380V power frequency power supply through a lead, and the wire outlet end of a voltage regulator T1 is connected with the primary side of a boosting transformer T2 through a lead. The secondary side of the step-up transformer T2 is connected with a silicon stack D by a lead, and the silicon stack D rectifies to charge the pulse capacitor bank C. After the charging voltage reaches a preset value, the pulse ignition ball gap 2 applies an ignition pulse through a pulse ignition device to realize breakdown discharge, so that an impact current injected into the test sample semi-closed micro-cavity device 9 is formed. Through the changed wave modulation inductance L and the changed wave modulation resistance R, impact current waveforms with different wave front time and half peak time can be obtained; by controlling the charging voltage of the pulse capacitor bank C, rush currents having different peak values can be obtained.

In order to realize the precise measurement of the impact current and the impact current value and provide measurement data for triggering the shooting of the high-speed camera 7, a core-through current sensor and a digital storage oscilloscope 5 are adopted to form a current measurement system. The core-through current transformer 4 is composed of a non-magnetic framework, a copper coil, an integrating circuit, a bayonet nut connector socket and a polymer insulation shell. The non-magnetic conducting framework is a circular ring which is made of a non-magnetic conducting polymer, and has the inner diameter of 2-10 cm, the outer diameter of 2.5-12 cm and the cross-section diameter of 1-4 cm. The function of the transformer is to fix the copper coil and simultaneously avoid saturation of the iron core of the core-through current transformer 4 when measuring impact large current. The copper coil is uniformly wound on a circular non-magnetic-conductive framework by a copper enameled wire with the wire diameter of 0.44-1.67 mm, the number of winding turns is 50-1000 turns, and outgoing lines at two ends of the copper coil are connected with the input end of an integrating circuit and used for integrating induced electromotive force, so that the change of current along with time t is obtained. The capacitive voltage divider 3 and the digital storage oscilloscope 5 form a voltage measuring system; the voltage division ratio is 1000:1, the measured amplitude is-400 kV, the frequency is 0-1 MHz of voltage signals, and the measured signals are not attenuated and deformed.

The digital storage oscilloscope 5 is powered by an independent power supply, can simultaneously acquire voltage signals with amplitude of-400V and frequency of 0-100 MHz in 2 signal acquisition channels, and has sampling frequency of 0-10 GS/s and storage capacity of 0-100 MB. Once the air gap in the semi-closed microcavity of the test sample semi-closed microcavity device 9 is broken down, the synchronous trigger 6 is sent by the digital storage oscilloscope 5 at the same moment to trigger the synchronous trigger 6 to send a plurality of signals to trigger a plurality of high-speed cameras 7 to start shooting the process of arc occurrence, development and dissipation.

The synchronous trigger 6 can receive the trigger signal of the digital storage oscilloscope 5, can receive the trigger signal in real time and synchronously send the trigger signal to a plurality of paths of output signals for controlling a plurality of high-speed cameras 7 to start a shooting mode.

The high-speed camera 7 has a 12-bit monochrome chip (36-bit RGB color), 20-micron pixel points, the frame rate can be adjusted according to pixels and can reach 1000000fps at most, and shooting parameters are controlled through software by installing software on the data processor 8. The high-speed camera 7 for shooting the arc image of the local area is also provided with a focusing lens with a focal length of 25 mm-85 mm.

Furthermore, the invention provides various ways of placing the high-speed camera 7:

the first method is as follows: the high-speed cameras 7 are connected with the synchronous trigger 6 through signal lines, and the high-speed cameras 7 are two high-speed cameras 7 which are vertically arranged at the same position. The arrangement mode realizes that the two high-speed cameras 7 simultaneously shoot images in the processes of generation, development and dissipation of the electric arc from the same direction, and the electric arc images obtained by shooting specific local areas can provide more detailed image materials for the shape change of the electric arc in the process of development.

The second method comprises the following steps: the two high-speed cameras 7 are symmetrically arranged by taking the test sample semi-closed micro-cavity device 9 as a midpoint. The placing direction realizes that one high-speed camera 7 shoots the whole image of the electric arc from the opposite direction, the other high-speed camera 7 shoots the specific local image of the electric arc, and the symmetry of the electric arc development and the uniformity of the electric arc distribution in the process of blowing out the electric arc by the multi-cavity structure in the test can be analyzed by comparing the images of the electric arc obtained by shooting the two cameras relatively, so that an intuitive image is provided for comparing the arc extinguishing performance of the cavity.

The third method comprises the following steps: the high-speed cameras 7 are connected with the synchronous trigger 6 through signal lines, and the high-speed cameras 7 are a plurality of high-speed cameras 7 which are arranged on an arc with the test sample semi-closed micro-cavity device 9 as the center of a circle at equal central angles. The placing mode shoots images of arc development and dissipation from different angles, the specific form of the arc is observed at multiple angles, the development and dissipation form of the arc in a three-dimensional space can be visually displayed according to the shot images, whether the spraying direction of the arc is parallel to a chamber nozzle or not is roughly judged according to the images, the diffusion trend of arc plasma is researched, and the placing mode has positive significance for improving the performance of a multi-chamber structure.

However, in the above method, one high-speed camera 7 is selected to shoot the whole arc image, and the other high-speed camera 7 is selected to shoot the local arc image. The high-speed camera 7 for shooting the whole image of the electric arc manually focuses, adjusts the size of an aperture, sets ISO (international standardization organization) light sensitivity, sets a frame rate of 1000-10000 fps in software of the data processor 8, and selects a trigger mode as central point trigger. The high-speed camera 7 for shooting the arc local image needs to be additionally provided with a telephoto lens to focus a local area, the size of an aperture is adjusted, the frame rate is set to be the same as that of the other high-speed camera 7 in software of the data processor 8, and the triggering mode is central point triggering. The cameras at different positions can be selected to shoot the whole arc image and the local arc image according to shooting requirements, and the shooting frame rate and the triggering mode are required to be ensured to be the same.

When the test observation device for transient gas discharge in the semi-closed microcavity is used for observing a gas discharge test in the semi-closed microcavity of the test sample semi-closed microcavity device 9, shooting can be performed according to the following shooting steps:

step one, determining the parameters of the test loop element: dividing the wave head time and the wave tail time of the actual lightning current by a simulation proportion n, calculating the wave head time and the wave tail time of the impact current of a simulation test, and changing the sizes of a wave regulating resistor R and a wave regulating inductor L in a loop of an impact current generator 1 to achieve the calculated wave head time and the calculated wave tail time of the impact current;

step two, checking whether the impulse current waveform meets the requirements: short-circuit wiring is carried out on two ends of a test sample semi-closed microcavity device 9, under the condition of short circuit, an impact current generator 1 is started to output impact current, and whether the current waveform meets the requirement or not is judged through the waveform displayed by a digital storage oscilloscope 5;

step three, determining the placing position of the high-speed camera 7 and adjusting shooting parameters: the method comprises the following steps of oppositely placing two high-speed cameras 7, wherein the placing height is the same as that of a test sample semi-closed micro-cavity device 9, adjusting the focal length of the cameras for shooting the whole image of the electric arc until a data processor 8 displays a clear image, additionally installing a long-focus lens for the cameras for shooting a local image, focusing until the data processor 8 displays the clear image of the local position, fixing the positions of the high-speed cameras 7 and the test sample semi-closed micro-cavity device 9, setting a frame rate to 2500fps through control software of the data processor 8, setting a trigger mode to be a central point trigger and ISO required light sensitivity parameters, and ensuring that the frame rate and the trigger mode of the two high-speed cameras 7 are the same;

step four, starting the test: the short-circuit connection wires at two ends of the test sample semi-closed micro-cavity device 9 are removed, the charging voltage value of the impulse current generator 1 is set, charging is started after the charging time is set according to the impulse voltage value, after the charging is finished, the impulse current generator 1 is triggered, meanwhile, the synchronous trigger 6 sends a trigger signal to the high-speed camera 7 to shoot an arc image, the frame rate of control software of the data processor 8 is adjusted according to the situation of the shot image, and the test is repeated for many times.

The digital storage oscilloscope 5 of the test observation device for transient gas discharge in the semi-closed micro-cavity is used as a trigger signal source for synchronous shooting of the high-speed camera 7. Therefore, when the air gap in the semi-closed microcavity of the test sample semi-closed microcavity device 9 is broken down, the digital storage oscilloscope 5 sends a trigger signal to the synchronous trigger 6 at the same moment, and the synchronous trigger 6 simultaneously sends a plurality of signals to trigger a plurality of high-speed cameras 7, so that the high-speed cameras 7 are synchronously started to shoot. The high-speed cameras 7 have the same shooting frame rate and the same trigger mode, and the shooting time of the plurality of high-speed cameras 7 is the same.

In order to further prove the feasibility of the experimental observation device for transient gas discharge in the semi-closed microcavity for carrying out experimental observation on gas discharge in the semi-closed microcavity of the test sample semi-closed microcavity device 9. The invention also provides a whole image of the shot transient arc developing to dissipating process and a local image of the shot transient arc; the captured transient arc progresses to an overall image of the dissipation process and a local image of the transient arc is captured as shown in fig. 3-4.

Therefore, the test observation device for transient gas discharge in the semi-closed micro-cavity can be further proved to be capable of solving the problem that synchronous shooting cannot be realized as long as shooting time needs to be preset and then electric arcs are generated in an actual semi-closed micro-cavity gas discharge test; and the problem that the arc form details are fuzzy due to the fact that only a large-range whole image can be shot and the arc image cannot be shot locally exists when the arc image is shot.