在電線電纜行業(yè)，我們經(jīng)常能聽(tīng)到“絕緣擊穿”這個(gè)詞，且較多發(fā)生在電力電纜的使用上，那么，電力電纜絕緣擊穿是什么意思呢？電氣成套設(shè)備廠家電纜告訴您：
In the wire and cable industry, we can often hear the word "insulation breakdown", and it occurs more in the use of power cable. So what does the meaning of insulation breakdown of power cable mean? The cable of the electrical complete equipment manufacturer tells you:
要明白，放電是發(fā)生電力電纜絕緣擊穿的原因
First, it should be understood that discharge is the reason for the insulation breakdown of power cable
放電指的是在兩個(gè)有電位差的導(dǎo)體之間，當(dāng)絕緣材料性能下降，兩個(gè)導(dǎo)體間產(chǎn)生了電子能量的遷移，比如高壓火線與地線間的打火就是放電，完全的放電是放電的瞬時(shí)有兩個(gè)電極間形成了完整的電弧通道。
Discharge refers to the transfer of electronic energy between two conductors when the performance of insulation materials decreases. For example, the ignition between high voltage wire and ground wire is discharge. Complete discharge means that the complete arc channel is formed between two electrodes in the instantaneous discharge.
除了以上所說(shuō)的放電情況外，還有放電的特殊情況——局部放電
In addition to the above mentioned discharge, there are also special discharge cases - partial discharge
局部放電主要有兩種情況
There are two main cases of partial discharge
1.在兩個(gè)導(dǎo)體之間有絕緣，當(dāng)絕緣材料內(nèi)部有缺陷，如雜質(zhì)、空隙、導(dǎo)體的尖 端等，會(huì)成絕緣內(nèi)部電場(chǎng)歧變，引起在絕緣內(nèi)部產(chǎn)生脈沖放電。
1. there is insulation between two conductors. When there is defect in the insulation material, such as impurities, voids, tip of conductor, etc., the electric field will be differentiated inside the insulation, which will cause pulse discharge in the insulation.
2.外部放電產(chǎn)生電暈也是局部放電的一種，在高電位與接地之間有空氣絕緣，當(dāng)導(dǎo)體周?chē)碾妶?chǎng)在某一點(diǎn)特別集中時(shí)，如導(dǎo)線毛刺，引起在空氣中產(chǎn)生脈沖放電，且沒(méi)有形成對(duì)地短路，形成電暈。
2. corona generated by external discharge is also a kind of partial discharge. Air insulation is provided between high potential and grounding. When the electric field around the conductor is specially concentrated at a certain point, such as the burr of the conductor, pulse discharge is generated in the air, and no short circuit to ground is formed to form corona.
局部放電的特征
Characteristics of partial discharge
局部放電也具有放電的基本特征，即有電子能量的遷移，由于放電能量較小，又有絕緣材料的阻擋，在兩個(gè)電極間不一定形成完整的電弧通道，此類(lèi)通道一旦出現(xiàn)就會(huì)加劇局部放電，直到形成兩極絕貫通，就會(huì)發(fā)生短路放電故障。
Partial discharge also has the basic characteristics of discharge, that is, the transfer of electronic energy. Because of the small discharge energy and the barrier of insulating materials, there is no complete arc channel between the two electrodes. Once such channels appear, the partial discharge will be intensified, and the short circuit discharge fault will occur until the two poles are completely connected.
局部放電形成的原因
The cause of partial discharge
主絕緣內(nèi)存在氣隙會(huì)引起局部放電。由于氣隙的相對(duì)介電常數(shù)遠(yuǎn)小于電纜絕緣，在工頻電場(chǎng)作用下，氣隙要承受較大的電場(chǎng)強(qiáng)度，千萬(wàn)局部放電，隨著氣隙的多次放電，氣隙通路不斷擴(kuò)大，放電量逐漸增加，直發(fā)生擊穿，造成電纜損壞。
The air gap in the main insulation will cause partial discharge. Because the relative dielectric constant of air gap is far less than cable insulation, under the action of power frequency electric field, the air gap should bear a large electric field intensity. Tens of millions of partial discharge, with the multiple discharge of air gap, the air gap path is expanding, and the discharge amount gradually increases until breakdown occurs, which causes cable damage.
主絕緣內(nèi)存在雜質(zhì)引起局部放電。雜質(zhì)的擊穿強(qiáng)度比絕緣材料小的多，在電場(chǎng)作用下，雜質(zhì)發(fā)生放電、炭化和氣化，生成氣隙，引起局部放電。
The impurity in the main insulation causes partial discharge. The breakdown strength of impurities is much smaller than that of insulating materials. Under the action of electric field, the impurities first discharge, carbonize and gasify, and generate air gap, which leads to partial discharge.
導(dǎo)體的尖 端、毛刺會(huì)引起局部放電。由于尖 端會(huì)使電場(chǎng)強(qiáng)度增加，尖 端周?chē)慕^緣材料先發(fā)生放電，進(jìn)而發(fā)展成擊穿，這就是我們常說(shuō)的尖 端效應(yīng)。
The tip and burr of conductor can cause partial discharge. Because the tip increases the electric field strength, the insulation around the tip first discharges and then develops into breakdown, which is what we often call the tip effect.
以上就是引起電力電纜絕緣擊穿的一些因素，在電纜的敷設(shè)使用中，一定要多加注意，一旦發(fā)現(xiàn)絕緣擊穿，可以參考以上的一些因素盡早找出問(wèn)題所在。
Above are some factors that cause insulation breakdown of power cable. In the laying and use of cables, more attention should be paid to. If insulation breakdown is found, we can refer to the above factors to find out the problem as soon as possible.
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