1. A micro-gap arc observation method is characterized by comprising the following steps:

s1: applying pressure to the metallized films to exhaust air between the metallized films;

s2: applying a breakdown voltage to the metallized film, wherein partial regions of the metallized film are overlapped, and the overlapped portion breaks down under the action of the voltage to form a breakdown region to generate an arc;

s3: light emitted by the generated arc is reflected and imaged to shoot the development process of arc morphology change in the breakdown process of the metallized film.

2. A method for observing a micro-gap arc as claimed in claim 1, further comprising the steps of: the current and voltage during the breakdown process are detected while photographing.

3. A micro-gap arc observing apparatus, comprising: the breakdown test platform is used for applying voltage to the metallized film and enabling the metallized film to break down to generate electric arcs; a measurement system, comprising: a reflection imaging mechanism for reflection imaging of light emitted by the generated arc; the shooting mechanism is used for shooting and imaging the received reflection imaging signal; and the measuring mechanism is used for detecting the current and the voltage in the breakdown process.

4. A micro-gap arc observing device according to claim 3, wherein the reflecting imaging mechanism is a flat mirror (18), and the flat mirror (18) is placed above the breakdown testing platform; the shooting mechanism is a high-speed camera (19), the shooting interval of the high-speed camera (19) is below the mu s level, and the high-speed camera is placed in front of the plane mirror (18) and is positioned on the same horizontal line with the plane mirror (18); the measuring mechanism is an oscilloscope (20).

5. A micro-gap arc observing device as claimed in claim 3, wherein the breakdown testing platform comprises a power supply module, a high and low potential generating module for applying high and low voltages to the metallized films (10, 11).

6. A micro-gap arc observing device as claimed in claim 5, wherein the high and low potential generating modules are two metal electrode compacts (12, 13), and the metal electrode compacts (12, 13) are connected with a power supply module for applying breakdown voltage to the metallized films (10, 11); an electric field is applied to the dielectric layer of the metallized film (10) to cause it to break down and create an arc.

7. A micro-gap arc observing device as claimed in claim 6, wherein the two metal electrode compacts (12, 13) are arranged in a staggered manner, and the metallized films (10, 11) are arranged under the metal electrode compacts so that partial areas of the metallized films are overlapped, and the overlapped parts are broken down under the action of voltage to form a broken-down area to form a capacitor.

8. A micro-gap arc observing device as claimed in claim 7, wherein the voltage is DC, AC or AC/DC composite voltage.

9. A micro-gap arc observation device as claimed in claim 3, wherein the breakdown test platform further comprises a hydraulic mechanism, the hydraulic mechanism is arranged above the breakdown test platform, and the cover plate (14) is used for applying a certain pressure to the metallized films (10, 11) and exhausting air between the two metallized films (10, 11).

10. A micro-gap arc observing device according to claim 9, wherein said cover plate (14) is a transparent material; the hydraulic machine is provided with a pressure sensor for measuring the applied pressure.

Background

In recent years, the metalized film capacitor has been widely applied in the fields of new energy automobiles, rail transit, pulse power technology, flexible direct current transmission and the like due to the excellent performance of the metalized film capacitor. The metallized film capacitor has the self-healing characteristic, can recover the insulation after local breakdown, can be manufactured into a dry structure, and has the characteristics of small energy volume, light weight, compact structure, high reliability and the like. Defects or impurities inevitably exist in the dielectric film of metallized film capacitors and are referred to as "electrical weaknesses". The breakdown field intensity of the area where the electric weak point is located is lower than that of the surrounding area, the electric weak point of the dielectric film can be broken down to form a discharge channel along with the increase of the external voltage at the two ends of the capacitor, the electric charges form a large current through the discharge channel, the local temperature is increased, so that the thin metal layer at the breakdown point is rapidly evaporated and outwards diffused, the electric arc is extinguished, the insulation of the capacitor is recovered, and the process is called self-healing.

Research shows that self-healing arc extinguishing of the metallized film is related to arc plasma density, so that observation of the metallized film self-healing arc is of great significance in research of a film breakdown mechanism and an arc development process in the self-healing process. However, since the film thickness of the metallized film is in the micron order, the arc observation belongs to the observation of the micro gap discharge phenomenon in the self-healing process of the metallized film, and the phenomenon is generally difficult to effectively observe. In the prior art, the research on the self-healing arc of the metallized film is only to measure the light intensity of the self-healing arc as a basis for judging the self-healing duration, or a spectrometer is used for analyzing the spectrum of the self-healing arc, and the observation on the self-healing arc of the metallized film is not realized.

Disclosure of Invention

In order to solve the technical problems, the invention provides a micro-gap arc observation method and device, which can observe the development process of arc morphology change in the breakdown process of a micron-sized thick metalized film, facilitate the research of the development mechanism of an arc in the self-healing process, and can be expanded to other micron-sized gap discharge observation fields.

In order to achieve the above object, the present invention provides a method for observing a micro-gap arc, comprising the steps of: applying pressure to the metallized films to exhaust air between the metallized films; applying a breakdown voltage to the metallized film, wherein partial regions of the metallized film are overlapped, and the overlapped portion breaks down under the action of the voltage to form a breakdown region to generate an arc; light emitted by the generated arc is reflected and imaged to shoot the development process of arc morphology change in the breakdown process of the metallized film.

Further, the method also comprises the following steps: the current and voltage during the breakdown process are detected while photographing.

A micro-gap arc observing apparatus comprising: the breakdown test platform is used for applying voltage to the metallized film and enabling the metallized film to break down to generate electric arcs; a measurement system, comprising: a reflection imaging mechanism for reflection imaging of light emitted by the generated arc; the shooting mechanism is used for shooting and imaging the received reflection imaging signal; and the measuring mechanism is used for detecting the current and the voltage in the breakdown process.

Further, the reflection imaging mechanism is a plane mirror, and the plane mirror is placed above the breakdown test platform; the shooting mechanism is a high-speed camera, the shooting interval of the high-speed camera is below the level of mu s, and the high-speed camera is placed in front of the plane mirror and is positioned on the same horizontal line with the plane mirror; the measuring mechanism is an oscilloscope.

Furthermore, the breakdown test platform comprises a power supply module and a high and low potential generation module, and applies high and low voltages to the metallized film.

Furthermore, the high and low potential generation module is composed of two metal electrode pressing blocks, and the metal electrode pressing blocks are connected with the power supply module and used for applying breakdown voltage to the metallized film; an electric field is applied to the dielectric layer of the metallized film to cause the metallized film to break down to generate an arc.

Furthermore, the two metal electrode pressing blocks are arranged in a staggered mode, the metallized film is arranged below the two metal electrode pressing blocks, partial areas of the metallized film are overlapped, and the overlapped portions are broken down under the action of voltage to form a breakdown area to form a capacitor.

Further, the voltage is a direct current voltage, an alternating current voltage or an alternating current-direct current composite voltage.

Furthermore, the breakdown test platform also comprises a hydraulic mechanism, wherein the hydraulic mechanism is arranged above the breakdown test platform, applies certain pressure to the metallized films through the cover plate, and exhausts air between the two layers of metallized films.

Further, the cover plate is made of a transparent material; the hydraulic machine is provided with a pressure sensor for measuring the applied pressure.

Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the metallized film is punctured to generate an electric arc through the puncture test platform, the development process of the appearance change of the electric arc in the puncture process of the micron-sized thick metallized film can be further observed through reflection imaging and shooting, the development mechanism of the electric arc in the self-healing process can be conveniently researched by combining the detection of the current and the voltage in the process, and the invention can be expanded to the other micron-sized gap discharge observation fields.

(2) According to the invention, the preferred reflection imaging mechanism is a plane mirror, the shooting mechanism is a high-speed camera for observing the arc morphology change in the metallized film breakdown process, and the device has a simple structure and strong operability.

(3) The use of level crossing can make the light reflection formation of image that the electric arc that produces launches shoot by high-speed camera to the horizontal direction, high-speed camera only need the tripod fix can in the horizontal direction, avoided high-speed camera directly shoot required hoist and mount fixed establishment directly over the breakdown test platform and lead to shooting the incomplete problem of formation of image because of hydraulic pressure mechanism position, to a great extent simplified the experiment operation.

Drawings

Fig. 1 is a schematic view of a micro-gap arc observation device according to an embodiment of the present invention.

FIG. 2 is a graph illustrating the observed arc topology change process of an embodiment of the present invention.

Fig. 3 is a diagram of a breakdown voltage current waveform according to an embodiment of the present invention.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein: 10, 11 are metallized films 12, 13 are metal electrode pressing blocks 14, cover plates 15, organic glass 18, a plane mirror 19, a high-speed camera 20 and an oscilloscope.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, there is shown a minute-gap arc observing apparatus according to an embodiment of the present invention, including: breakdown test platform and measuring system; the breakdown test platform is used for applying voltage to the metallized film and enabling the metallized film to break down to generate electric arcs; the measuring system is used for measuring the voltage and the current of the metallized film in the breakdown process and shooting the development process of the breakdown arc; the measurement system includes: reflection imaging mechanism, shooting mechanism, measuring mechanism.

The breakdown test platform includes metal electrode compacts 12 and 13, a hydraulic mechanism (not shown in fig. 1, a cover plate 14, and a power supply (not shown in fig. 1).

The electrical connection between the power supply and the metallized film is preferably in the form of metal compacts, namely metal electrode compacts 12 and metal electrode compacts 13 which are respectively pressed on the metal layers of the metallized film 10 and the metallized film 11; the power supply is connected with the metal electrode pressing block 12 and the metal electrode pressing block 13, and applies breakdown voltage to the metallized film 10 and the metallized film 11, wherein the applied voltage can be direct current voltage, alternating current voltage or alternating current-direct current composite voltage. The positive pole of the power supply is connected to the metal electrode pressing block 13, and provides a high-voltage potential HV for the metallized film during breakdown, the negative pole of the power supply is connected to the metal electrode pressing block 12, and provides a low-voltage potential GND for the metallized film during breakdown; an electric field is applied to the dielectric layer of metallized film 10 to cause it to break down and create an arc.

The metallized film 10 is laid on the organic glass 15, the metallized film 10 and the metallized film 11 are both metal layers on the upper sides, partial areas are mutually overlapped, and the overlapped parts can be broken down under the action of voltage to form a breakdown area to form a capacitor.

Besides the metal pressing block mode, the electrical connection between the power supply and the metallized film can also adopt the modes of a metal clamp and a bolt nut, and the two modes are complex to operate and are not suitable for the puncture test needing to repeatedly replace the sample. In addition, a breakdown test may be performed using a single-layer metallized film as a sample, a plate electrode as a low-voltage electrode below the metallized film, and a needle electrode as a high-voltage electrode above the metallized film.

The hydraulic mechanism is arranged above the breakdown test platform, certain pressure is applied to the metallized films 10 and the metallized films 11 through the cover plate 14, air between the two metallized films is exhausted, and the hydraulic mechanism is further provided with a pressure sensor for measuring the applied pressure.

The cover plate 14 covers the upper side of the metal electrode pressing block 13, the cover plate 14 is made of transparent materials, certain mechanical strength needs to be met, pressure provided by the hydraulic mechanism can be borne, and the cover plate 14 is preferably made of organic glass.

The measurement system includes: the device comprises a reflection imaging mechanism used for reflecting and imaging light emitted by the generated electric arc, a shooting mechanism used for shooting and imaging the received reflection imaging signal, a measuring mechanism used for detecting current and voltage in the breakdown process, and a monitoring mechanism used for monitoring the development process of arc morphology change in the breakdown process of the metallized film.

Preferably, the reflective imaging means is a flat mirror 18, and the flat mirror 18 is placed above the breakdown test platform, preferably at 45 ° to the horizontal, for reflecting the light emitted by the arc to the horizontal for being photographed by the photographing means.

Preferably, the shooting mechanism is a high-speed camera 19, the shooting interval of the high-speed camera 19 is less than the mu s level, the high-speed camera 19 is placed in front of the plane mirror 18 and is on the same horizontal line with the plane mirror 18, and the distance between the high-speed camera 19 and the plane mirror 18 is such that the shooting range of the high-speed camera 19 at least covers the breakdown area.

Preferably, the measuring mechanism is an oscilloscope 20, and is used for measuring the voltage and the current of the metallized film 10 and the metallized film 11 in the process of breakdown, and the high-speed camera 19 is triggered by the current after the metallized film 10 and the metallized film 11 are broken down, and is triggered by a TTL signal sent by the oscilloscope 20.

The invention discloses a micro-gap arc observation method, which comprises the following steps:

s1: applying pressure to the metallized films to exhaust air between the metallized films;

s2: applying a breakdown voltage to the metallized film, wherein partial regions of the metallized film are overlapped, and the overlapped portion breaks down under the action of the voltage to form a breakdown region to generate an arc;

s3: light emitted by the generated electric arc is reflected and imaged, and the development process of the appearance change of the electric arc in the breakdown process of the metallized film is shot; the current and voltage during the breakdown process are detected while photographing.

Specifically, the thickness of the metallized film used in the embodiment of the present invention is 6 μm, the dielectric material is a biaxially oriented polypropylene film BOPP, the electrode material is zinc aluminum, the breakdown region is 20mm × 50mm, the cover plate 14 is made of organic glass, the pressure provided by the hydraulic mechanism to the metallized film 10 and the metallized film 11 through the cover plate 14 is 20kPa, and the shooting interval of the high-speed camera 19 is 1.66 μ s. The observed arc topology change process after the metallized film 10 and the metallized film 11 break down is shown in fig. 2. The voltage measurement adopts a high-voltage probe to directly measure the voltage between the metal electrode pressing block 12 and the metal electrode pressing block 13; the current measurement adopts the form of sampling resistance, a non-inductive resistor is connected in series in an experimental loop, the current is reversely pushed out through the voltage on the measuring resistor, the breakdown voltage and the current waveform obtained by the measurement of the oscilloscope 20 are shown in figure 3, the breakdown voltage is 3.78kV, the peak current is 2A, and the observed self-healing duration is 14.3 mu s. The development mechanism of the electric arc in the self-healing process can be further researched according to the electric arc development process observed by the device, and the device can be expanded to the other micron-sized gap discharge observation fields.

In addition, the preferable reflection imaging mechanism is a plane mirror, the shooting mechanism is a high-speed camera, the measuring mechanism is an oscilloscope, the device is simple in structure and strong in operability, the duration of the self-healing arc development process of the metallized film is in the order of microseconds to tens of microseconds, and through the embodiment, the observed self-healing duration is 14.3 microseconds, namely the self-healing device completely meets the test requirement.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.