使用觸發(fā)方法對(duì)固定間隙中真空斷路器的電弧進(jìn)行調(diào)查

1、Investigation of the Arc of a Vacuum Circuit Breaker in a fixed Gap using the Triggering method.使用觸發(fā)方法對(duì)固定間隙中真空斷路器的電弧進(jìn)行調(diào)查。Abstract摘要When the contacts of a Vacuum circuit breaker (VCB) with current flowing through it, is separated, an arc is generated.當(dāng)電流流過(guò)真空斷路器（VCB）的觸點(diǎn)分離時(shí)，產(chǎn)生電弧。The Arc is usually supp

2、orted by ionized gas or ionized metal vapour derived form the metal contact. 電弧通常由電離氣體或從金屬接觸形成的離子化金屬蒸氣形成的。This arc is an essential component of the interrupting process and capability of the Vacuum circuit breaker. 該電弧是真空斷路器的中斷過(guò)程和能力的重要組成部分。The object of this paper is to trigger, record, observe and

3、analyze the dynamic image of the Vacuum arc when it ignites in a short gap and at a low voltage.本文的目的是觸發(fā)，記錄，觀察和分析真空電弧在短間隙和低電壓下點(diǎn)燃的動(dòng)態(tài)圖像。A CMOS high speed digital camera will be used to record the images of the arc. CMOS高速數(shù)碼相機(jī)將用于記錄電弧圖像。The characteristics of the arc in its diffused and constricted stat

4、e, the degree of changes between the two states, and the direct relationship between the voltage and current will also be observed. 將觀察電弧在擴(kuò)散和收縮兩種狀態(tài)之間的變化程度以及電壓和電流之間的直接關(guān)系The life time of the Vacuum arc will be 10ms.真空電弧的壽命為10ms。1 Introduction 引入VCB is one of the simplest circuit breakers. VCB是最簡(jiǎn)單的斷路器之

5、一。Its design and construction consist of one fixed pole and one moveable contact placed in a vacuum vessel. 其設(shè)計(jì)和結(jié)構(gòu)由放置在真空容器中的一個(gè)固定桿和一個(gè)可動(dòng)觸頭組成。Its application has now been widely accepted in electric power system, especially in the medium voltage region. 其應(yīng)用現(xiàn)已廣泛接受電力系統(tǒng)，特別是在中壓區(qū)域。Today it has largely repla

6、ced other arc-type interrupting devices and its main advantages include, its compact design, maintenance free, long life operation, has a very good environmental compatibility and its excellent interruption and dielectric recovery characteristics which can interrupt the high frequency current result

7、ing from the arc instability. 今天它已經(jīng)在很大程度上取代了其他電弧型中斷裝置，其主要優(yōu)點(diǎn)包括緊湊型設(shè)計(jì)，免維護(hù)，使用壽命長(zhǎng)，具有很好的環(huán)境兼容性，優(yōu)異的中斷和介電恢復(fù)特性（可中斷由電弧不穩(wěn)定引起的高頻電流）The characteristic of the vacuum arc have been of paramount importance for the successful interruption of short Circuit currents in medium voltage circuits. 真空電弧的特性對(duì)于中壓短路電流的成功中斷至關(guān)重要。

8、The arc exits in two forms, the diffused and constrict state.電弧以兩種形式出現(xiàn)，即擴(kuò)散和收縮狀態(tài)。At low currents, up to 10 kA, the arc burns in diffused mode, so that the breakers contacts erosion and heating is acceptable. 從低電流到10 kA，電弧以擴(kuò)散模式燃燒，使斷路器接觸腐蝕和溫升在允許范圍。But currents greater than 10 kA, the constriction of th

9、e arc caused by energy supplied to the Vacuum contact making it difficult for the gap to extinguish the arc at the instant of Current zero. 但是大于10 kA的電流，由于提供給真空接觸器的能量引起的電弧的收縮使得間隙在電流零點(diǎn)瞬間熄滅電弧是困難的。The breaking capacity and reliability of interrupters depend greatly on the controlling of the vacuum arc.

10、 斷路器的斷路能力和可靠性在很大程度上取決于真空電弧的控制。Several researches have been carried out recently on methods of controlling the characteristics of the arc to keep it in its diffused state in order to design new type interrupters for high-voltage and high current power distribution. 近來(lái)已經(jīng)對(duì)控制電弧特性的方法進(jìn)行了幾項(xiàng)研究，保持其處于擴(kuò)散狀態(tài)以設(shè)計(jì)用

11、于高壓和大電流配電的新型斷路器。To record the image of the arc changing from constricted form into a diffused form and analysis its characteristics, an experimental setup and a mathematic model of vacuum arc was used. 為了記錄從收縮形式變化為弧形的弧的圖像并分析其特征，使用了真空電弧的實(shí)驗(yàn)裝置和數(shù)學(xué)模型。The recorded images and the mathematical model theory

12、of controlling the vacuum arc are analyzed and can be used to improve the quality and reliability of vacuum circuit interrupters. 通過(guò)分析記錄圖像和控制真空電弧的數(shù)學(xué)模型理論，以提高真空斷路器的質(zhì)量和可靠性。2.Experimental set-up 實(shí)驗(yàn)裝置The circuit diagram of the experiment is shown in Fig.1; 實(shí)驗(yàn)電路圖如圖1所示。While Fig.2 shows Physical arrangemen

13、t of the equipment set-up in the experiment. 而圖2顯示了實(shí)驗(yàn)中設(shè)備設(shè)置的物理布置。The list of equipment consists of: 設(shè)備清單包括：1. Ultra high Vacuum test champers with two glass windows for Arc observation. 超高真空試驗(yàn)箱，帶有兩個(gè)玻璃窗用于電弧觀察。2. Capacitor bank C0 電容器組3. isolation transformer 隔離變壓器4. Mechanical pump 機(jī)械泵5. Wave scope 示波

14、器6. Inductor Lo 電感器The Mechanical pump evacuates the vacuum in the champers of any impurities and moisture to a vacuum level of less than6.66Pa. 機(jī)械泵將所有雜質(zhì)和水分中的真空抽真空至小于6.66PaThe Co supplies a high arc current through L0 at a frequency of 50Hz to the contact gap. Co通過(guò)L0以50Hz的頻率向接觸間隙提供高電弧電流。The triggeri

15、ng pole placed at the centre of the hole of diameter 2mm in the cathode ignites the arc. 放置在陰極直徑2mm的中心的觸發(fā)極會(huì)點(diǎn)燃電弧。The contacts and electrode were isolated from both the chamber and ground. 觸點(diǎn)和電極從腔室和地面分離。The current transformer CT and potential transformer PT were used to observe and measured the V-I c

16、haracteristic of vacuum arc. 電流互感器CT和電壓互感器PT用于觀察和測(cè)量真空電弧的V-I特性。The system used for recording the arc images is shown in Fig.4。用于記錄電弧圖像的系統(tǒng)如圖4所示。The system is made up of: 系統(tǒng)由以下幾部分組成：1. A vacuum arc, 真空電弧2. An Optical system (including filters and convex), 光學(xué)系統(tǒng)（包括濾光片和凸面）， 3. An Image Capture tools (incl

17、uding CMOS camera and A/D Converter) 圖像捕獲工具（包括CMOS攝像頭和A / D轉(zhuǎn)換器）4. An Image data transfer and storage / system interface to the wave scope and CRT 圖像數(shù)據(jù)傳輸和存儲(chǔ)/系統(tǒng)接口到波段和CRT5. A Voltage and current waveform analyzer 電壓和電流波形分析儀6. A CRT CRT(“陰極射線顯像管”，是一種使用陰極射線管（Cathode Ray Tube）的顯示器。主要有五部分組成：電子槍（Electron Gu

18、n）、偏轉(zhuǎn)線圈（Deflection coils）、蔭罩(Shadow mask)、高壓石墨電極和熒光粉涂層(Phosphor)及玻璃外殼。它是應(yīng)用最廣泛的顯示器之一，CRT純平顯示器具有可視角度大、無(wú)壞點(diǎn)、色彩還原度高、色度均勻、可調(diào)節(jié)的多分辨率模式、響應(yīng)時(shí)間極短等LCD顯示器難以超過(guò)的優(yōu)點(diǎn)，而且價(jià)格更便宜。)A. Triggering circuit 觸發(fā)電路The triggering circuit is shown in Fig. 3.觸發(fā)電路如圖3所示It is made of two parts: 它由兩部分構(gòu)成1. High pulse voltage circuit, 高脈沖

19、電壓電路2. High current circuit. 大電流電路。The high pulse voltage circuit which consists of R1, V1 and C1, produces a high pulse voltage to breakdown the vacuum dielectric; while the high current circuit made of R2, V2 and C2, provides successive energy enough to keep the vacuum arc burning. 由R1，V1和C1組成的高脈沖

20、電壓電路產(chǎn)生高脈沖電壓以擊穿真空電介質(zhì);而由R2，V2和C2組成的大電流電路提供足夠的能量來(lái)保持真空電弧燃燒。The high-voltage silicon stack SS provides a discharge path, and also insulates the high current circuit from the high pulse voltage circuit. 高壓硅堆SS提供放電路徑，并且使高電流電路與高脈沖電壓電路絕緣。 Fig.6 shows the wave of the pulse voltage between A and B produced by

21、capacitor C1. 圖6示出了由電容器C1產(chǎn)生的A和B之間的脈沖電壓的波形。3. Observation of the Arc The camera and the triggering circuit were first set up respectively.首先設(shè)置相機(jī)和觸發(fā)電路。The speed of the camera is set to 3.2secs at a resolution 1280128, while the life span of vacuum arc is about 10ms, so the camera is first triggered an

22、d then the arc ignited. 相機(jī)的速度設(shè)置為3.2秒，分辨率為1280128，而真空電弧的使用壽命約為10ms，因此應(yīng)先觸發(fā)相機(jī)，然后電弧點(diǎn)亮。400 images of the ignited arc was captured, the images showing the cathode spots movement, transition of vacuum arc from constriction to diffusion state and anode spots movement etc. 拍攝了400個(gè)點(diǎn)火電弧圖像，顯示陰極點(diǎn)運(yùn)動(dòng)，真空電弧從收縮轉(zhuǎn)變到擴(kuò)散狀

23、態(tài)，陽(yáng)極點(diǎn)運(yùn)動(dòng)等。Vacuum Arc Analysis Mathematical Model Fig.5 shows a model of the experiment set-up to observe the vacuum arc in a vacuum circuit breaker. 真空電弧分析 - 數(shù)學(xué)模型圖5為在真空斷路器中觀察真空電弧的實(shí)驗(yàn)設(shè)置模型。The following assumptions are made: 做出以下假設(shè)：1. C1 the capacitance between anode and shield陽(yáng)極和屏蔽間的電容2. C2 the capacit

24、ance between cathode and shield陰極和屏蔽間的電容3. R1 the resistance between anode and shield 陽(yáng)極和屏蔽間的電阻4. R2 the resistance between cathode and shield 陰極和屏蔽間的電阻5. U0 the voltage between anode and cathode陽(yáng)極和陰極之間的電壓6. U1 the voltage between anode and shield 陽(yáng)極和屏蔽之間的電壓7. U2 the voltage between cathode and shie

25、ld陰極和屏蔽之間的電壓8. U4 the voltage between shield and ground屏蔽與地面之間的電壓From fig 5 the voltage relation equation is given by: 從圖5可以看出，電壓關(guān)系式由下式給出：the arc does not only spread between the vacuum gap but also spreads to the space between the shields and the electrodes, the rate reaching the shield is more if

26、the current the of the vacuum arc is high, resulting in the presence of metal vapour in this space and since there is also a resistance between the electrode and the shield: 電弧不僅在真空間隙之間擴(kuò)散，而且擴(kuò)散到屏蔽和電極之間的空間，如果真空電弧的電流大，則達(dá)到屏蔽的速率更高，導(dǎo)致在此處存在金屬蒸氣，而且電極和屏蔽之間也有電阻：Formula 5 then becomes: 公式5然后變成：if the arc ignit

27、es only between the contact gap ,RI and R2 is negligible, that is no resistance exits between space and contact equation (1) and (3) becomes: 如果電弧僅在接觸間隙之間點(diǎn)燃，則RI和R2是可以忽略的，他們之間沒(méi)有電阻，則空間方程和接觸方程（1）和（3）變?yōu)椋築ut when the arc of the Vacuum Arc is large enough to cause metal vapour movement to the space betwee

28、n the electrode and the shield, the will be resistance between the space and the contact, the resistance is given by: 但是，當(dāng)真空電弧的弧度足夠大以使金屬蒸汽移動(dòng)到電極和屏蔽之間的空間時(shí)，空間和觸點(diǎn)之間將產(chǎn)生電阻，電阻由下式給出：from equation 8 and 9 it can be seen that if the intensity of the arc is large then it will cause metal vapour movement to the

29、 space between the shield and the contact, and also the arc will constrict longer and strong enough to damage the surface of the breakers contact, so it is necessary to control the intensity of the arc and prevent it from constricting and keep it in a diffuse and stable arcing state. 從等式8和9可以看出，如果電弧

30、強(qiáng)度大，則會(huì)導(dǎo)致金屬蒸汽在屏蔽和觸點(diǎn)之間移動(dòng)，并且電弧會(huì)收縮較長(zhǎng)而足夠強(qiáng)，破壞斷路器的接觸面，因此有必要控制電弧的強(qiáng)度，防止電弧被收縮并保持在漫反射穩(wěn)定的電弧狀態(tài)。Applying a magnetic field on a vacuum arc is an effective method of maintaining a diffuse arc even at high current in the Vacuum circuit breaker. 在真空電弧中施加磁場(chǎng)是在真空斷路器中即使在高電流下仍保持漫反射電弧的有效方法。Many Manufacturers have used this

31、 method to design vacuum circuit breakers with stable and diffuse Arc at high voltage and current level. 許多制造商已經(jīng)使用這種方法在高電壓和電流水平設(shè)計(jì)具有穩(wěn)定和漫反射電弧的真空斷路器。Two methods, namely the AMF Axial Magnetic field and RMF Radial magnetic field are used to apply a magnetic field to the arc of the Vacuum Arc, ensuring t

32、hat there is less contact erosion and also improving the switching capacity of the interrupters 使用兩種方法，即AMF軸向磁場(chǎng)和RMF徑向磁場(chǎng)對(duì)真空電弧的磁場(chǎng)施加磁場(chǎng)，確保接觸侵蝕較少，并且還提高斷續(xù)器的開關(guān)容量4. Experimental Results 實(shí)驗(yàn)結(jié)論During the Experiments the following assumptions were made: 在實(shí)驗(yàn)期間，做出了以下假設(shè)：1. voltage of the capacitor C0 is set to 200

33、V. 電容器C0的電壓設(shè)定為200V。2. The gap between the electrodes is about 8 mm. 電極之間的間隙約為8毫米。3.Optronis-Camracord High-speed camera Ca 1000, Max-Revolution=12801024, Max-sampling freq=200,000.Fps .Optronis-Camracord高速攝像頭Ca 1000，最大公轉(zhuǎn)= 12801024，最大采樣頻率= 200,000.FpsA. V-I Characteristics. 伏安特性The relationship betwe

34、en the peak voltage and Peak current a very important characteristic of the vacuum arc is indicated in Fig 6. 峰值電壓和峰值電流之間的關(guān)系是真空電弧的一個(gè)非常重要的特性，如圖6所示。It shows the voltage-current characteristic of vacuum arc at different length of the short gap. 不同長(zhǎng)度短間隙的真空電弧的電壓 - 電流特性如圖所示。B. Images of vacuum arc 真空電弧圖像D

35、uring the whole optical test process to observe the igniting of the arc at 10ms, 400 frames images of vacuum arc were recorded with a high speed CMOS Video camera the images are shown in Fig 7. 在整個(gè)光學(xué)測(cè)試過(guò)程中，在10ms觀察電弧點(diǎn)火，用高速CMOS攝像機(jī)記錄400幀真空電弧圖像，圖像如圖7所示。These images show some characteristics of vacuum arc

36、. 這些圖像顯示出真空電弧的一些特征。It shows that the arc has five distinct stages: 這表明電弧有五個(gè)不同的階段：1.The Initial stage of the arc: The arc immediately after the ignition-images 1 - 3. , this is at the point when the arc was triggered between the triggering electrode and the anode and resulting in the initial plasma b

37、etween the main gap anode and the cathode .弧的初始階段：即刻點(diǎn)火圖像1-3之后的電弧，這是觸發(fā)電極和陽(yáng)極之間電弧觸發(fā)的時(shí)刻，在主間隙陽(yáng)極與陰極之間產(chǎn)生初始等離子體。 2.Constricted stage 1: image 4-6 the arc just begin to get into its constriction stage and is yet to attain its max value, it begins to spread quickly from the cathode to the anode 收縮階段1：圖像4-6，弧開

38、始進(jìn)入其收縮階段，并且尚未達(dá)到其最大值，它開始從陰極迅速擴(kuò)展到陽(yáng)極3.The constrict stage: images 7-9 the constricted arc attains it max value and is strongest at the stage and can melt the anode contact and forms several spots on the surface. 收縮階段：圖像7-9，收縮電弧達(dá)到最大值，在階段最強(qiáng)，可以熔化陽(yáng)極接觸并在表面形成幾個(gè)點(diǎn)。4.The Diffuse stage: images 10-12 here the arc

39、 begins to quench and becomes weak and starts to die down and migrates to the outer space and breaks up into spots between the gaps. 漫射階段：這里的圖像10-12開始熄滅，變?nèi)酰_始死亡，并移動(dòng)到外部空間，并分裂成間隙之間的斑點(diǎn)。5.Quenching Stageimages 13-15), this is when the arc beings to finally extinguish, the current of the Arc decreases qu

40、ickly and the intensity of the arc disappears at the surface of the anode. 熄滅階段圖像13-15），這是當(dāng)電弧終于熄滅時(shí)，電弧電流迅速下降，電弧強(qiáng)度在陽(yáng)極表面消失。The arc disintegrates into several light spots called cathode spots moving at high speed on the surface until it all finally disappears or extinguishes. 電弧分解成表面高速移動(dòng)的稱為陰極點(diǎn)，直到它們?nèi)肯Щ?/p>

41、熄滅。5. Conclusion. 結(jié)論Understanding the behavior and the thermodynamics of the Vacuum arc of a VCB circuit breaker is very necessary to improve the performance, efficiency, design and the correct functioning of the interrupter. 了解VCB斷路器真空電弧的行為和熱力學(xué)對(duì)于提高斷路器的性能，效率，設(shè)計(jì)和正確的功能是非常必要的。Generally there are three

42、methods to produce an arc in a vacuum namely, Draw Arc, inducing Arc and the triggering arc. 通常有三種在真空中產(chǎn)生電弧的方法，即繪制弧，誘導(dǎo)電弧和觸發(fā)電弧。The triggering method was used in this paper to record the arc intensity, the constriction and diffusion changes in the arc.本文采用觸發(fā)方法記錄電弧強(qiáng)度，電弧中的收縮和擴(kuò)散變化。About 400 images were collected at a speed of 4000fps and 1280 x 1024 pixel during the investigation.在調(diào)查期間以4000fps和12801024像素的速度收集了約400張圖像。The investigation of the arc within a 10m