江蘇春晨電纜有限公司：http://m.liuyangwu.com/st82365/
江蘇春晨電纜有限公司專業(yè)生產(chǎn)YCBPG扁電纜，移動橡套扁電纜，移動屏蔽橡套扁電纜，YCBPG扁電纜帶鋼絲屏蔽扁電纜，
Formation of branch discharge in plastic cable
Plastic insulated power cable operation reliability, in addition to the poor performance of insulation material itself, the decision factor is the improvement of the cable insulation structure. Deterioration of the electric field in the cable insulation will lead to field emission, leading to power generation and water branch, which will eventually cause the cable insulation layer to be broken down. The operation life of the plastic power cable is closely related to the aging phenomenon in the insulation of the insulation, which was discovered in the 20 world in 60s and 70s. Due to the discovery of the "pre breakdown" phenomenon of plastic cable before breakdown, it has aroused great interest in the world of cable manufacturing industry.
樹枝老化簡介
Branch aging
The organic material tree was due to the material internal micro cracking caused by the cracking of the small channel as the winter leaves no dendritic branches, branches, branches, buds. "Branches" is the general designation of the hollow cracking phenomenon. In fact, its shape has greatly surpassed the concept of "branch".
塑料電纜的樹枝化放電現(xiàn)象也是固體介質(zhì)擊穿前漫長的先導擊穿過程，在引發(fā)樹枝萌芽之前已有漫長的誘導（誘發(fā)）期。樹枝引發(fā)后，或者很快發(fā)展到固體擊穿，或者經(jīng)漫長的發(fā)展（老化）過程，zui后導致固體介質(zhì)擊穿（電老化擊穿）。樹枝放電通常指樹枝的發(fā)生、發(fā)展的全過程，也有特指管道細微開裂中的氣體的局部放電。
The branch of plastic cable discharge phenomenon is also a long time before the breakdown of solid dielectric breakdown process, in the initiation of the bud before the long induction period (You Fa). After the initiation of the branches, or soon after the development of solid breakdown, or the long development (aging) process, and finally lead to solid dielectric breakdown (electrical aging breakdown). Branch discharge usually refers to the occurrence and development of the branch, and also the partial discharge of the gas in the micro cracking of the pipe.
All kinds of organic materials, caused by the pipeline cracking can be subtle, original submicroscopic cracks exist; or the air gap, water and chemical impurities exist; or without any crack, but high field result in cold electron emission, causing cracks, this is very complex physical and chemical processes. From the high field strength, air gap, water hole, impurities, such as the core of the core, to the three direction of the three-dimensional space development. Is generally along the direction of the power line, but also because of the anisotropy of the material and the emergence of vertical power line direction of the branch. These branches extend to the pole (the entire insulation thickness), and finally the whole breakdown occurs. It can be a few minutes, a few minutes, a few years, or more than a few minutes, a few minutes, a few years, or more than a few minutes.
樹枝放電的形成
Formation of branch discharge
樹枝放電的引發(fā)和發(fā)展過程可分為以下四個階段：
The initiation and development of branch discharge can be divided into the following four stages:
。
(1) initiation period: also called latency period or induction period, it is the length of the degree of difficulty to characterize the occurrence of the branch. This is the main stage of the inhibition of the branches.
(2) growth period: also known as the development period, it shows that the growth rate of the tree branches triggered. Resistance to the development of good characteristics of the material, the development of slow growth, that is, a long period of growth.
(3) saturation period: when the branches develop to a certain length, the branches stop development, this period of time is called saturation period. The existence of the saturation period is due to the partial discharge and high energy electron bombardment of the polymer molecular chain, which leads to the decomposition of the material to produce a large amount of gas. With the enhancement of this effect, the internal pressure in the pipe increase, according to the law in Bashin, pipeline discharge voltage will be increased. Thus, in the case of constant external voltage, the development of branches may stop. Trying to prolong the saturation period is another important way to inhibit the branches.
(4) the gap breakdown: after saturation period, air gap or branch pipe for gas discharge decomposition of the material itself gradually through penetration, diffusion and escape, the pipeline gas pressure drop, Bashin according to law, then the breakdown voltage of air gap decreases, thus the branches and rapid development.
樹枝放電的分類與特點
Classification and characteristics of branch discharge
在實際中存在的多種樹枝放電形式可分為三大類：即電樹枝、水樹枝和化學樹枝。
In the actual existence of a variety of branches can be divided into three types of discharge can be divided into categories: the branches, water and chemical branches.
(1) electrical tree branch. In the high field of discontinuous material interface (both inside and outside the air gap, impurities, cable semi conductive layer interface) are particularly vulnerable to lead generation branches, branches often electric micro crack in high field strength concentrated into cracks or cracks formed at the branches sprout, continuous, hollow branch pipes, some material branch pipe wall with carbon particles. Partial discharge is usually accompanied by long and thin electrical branches.
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(2) water branch. Lead to gaps in the branches contain moisture. Water running cables, wire core water into the cable, insulation moisture content of the cable easily lead to water branches. The water branch is produced under the condition of the same electric field and water. However, the water branch can be triggered when the electric field is much lower than the electric field. There is no partial discharge in water branch. The types of water branches are also a lot of damage to the cable is also great. But the water tree has the characteristics of disappearance and reappearance of the. Some of the water heating, drying, vacuum pumping branches will disappear form, immersion in hot water will revive, the pipeline has closed branches indicates that the water disappeared, after cracking material slight rebound, but did not make the structure decomposition. In the actual cable, dry process of crosslinked polyethylene cables are rarely found in water branches, and wet manufacturing of crosslinked polyethylene cables are often seen in water.
XLPE insulated power cable body inevitably has micro manufacturing defects in the manufacturing process, such as micropore, impurities, and power cables in the transportation, installation, installation and operation of the process such as main insulation and sheath mechanical stress damage, terminal and intermediate joint installation quality, on-site construction conditions and technical quality control staff unfavorable factors, as the water slowly invaded (adsorption, diffusion and migration), synergistic effect of cable insulation defects in XLPE medium field, moisture and impurities etc., gradually produced
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