带电作业用绝缘工具

带电作业用绝缘工具应具有良好的电气绝缘性能、高机械强度，同时还应具有吸湿性低、耐老化等优点。为了现场作业的方便，绝缘工具还应质量轻、操作方便、不易损坏。目前带电作业用绝缘工具大致可分为硬质绝缘工具和软质绝缘工具二大类。硬质绝缘工具主要指以绝缘管、棒、板为主绝缘材料制成的工具，软质绝缘工具主要指以绝缘绳为主绝缘材料制成的工具。绝缘材质的性能直接影响和决定着工具的电气和机械性能。
1.绝缘杆 
　　玻璃纤维、环氧树脂和偶联剂是构成绝缘杆的主要成分。绝缘杆的制造方法较多，其中用于制造绝缘杆的主要工艺有湿卷法、干卷法、缠绕法和引拔法等。
　　绝缘杆的老化有整体老化和部分老化二个方面。整体老化主要是指受潮、长时间的整体材质老化；部分老化主要是指绝缘杆顶端长期在强电场作用下，因局部滑闪、漏电、放电而引起的材质老化。尤其对于500kV带电作业用工具，强电场造成的部分材质老化，使工具整体的绝缘距离减小，易于形成事故隐患，应采用定期监测的方式。验收试验中，试验电压过高会引起电晕或流柱放电，通过离子轰击侵蚀绝缘材料，电子则破坏绝缘的化学键，致使有机材料劣化，由此产生的导电沉积物在接近电极端部的高场强区起到延长电极的作用，从而导致材料的进一步劣化。因此，在检验性试验中选择适当的试验电压也是很重要的。　
　　操作杆表面的污秽状态对操作杆的闪络性能影响很大。据国外试验结果表明，表面污秽后，特别是沉积物受潮并导电时，耐闪络强度会严重降低。这是因为当绝缘杆表面有脏污而大气湿度又较高时，沿绝缘杆的电压分布更趋不均匀，高场强处将出现辉光放电，使沿绝缘杆表面的泄漏电流具有跃变的特点。国外对带电作业操作杆进行盐雾及人工污秽试验，测定盐雾、工业烟雾的凝聚、沉积物及意外污垢对操作杆的可能影响。试验结果表明，甚至在低电导率的雾里，泄漏电流也远大于可感知的1mA电流，操作杆表面材料的特性，纵向缺损及其他的不均匀性对受潮及污秽状态下的闪络性能影响较大。
　　几十年来，我国带电作业用绝缘杆的材料及制作工艺不断改进。引拔成型工艺增强了绝缘材料的致密性和成型杆的抗弯特性，使绝缘材料的渗水性大大降低，防潮性也得到了显着的提高。目前产品性能已达到国际先进水平，部分技术指标甚至优于国外同类产品。
2.绝缘绳  
　　绝缘绳索是广泛应用于带电作业的绝缘材料之一，可用作运载工具、攀登工具、吊拉绳、连接套及保安绳等。以绝缘绳为主绝缘部件制成的工具为软质绝缘工具。软质绝缘工具具有灵活、简便、便于携带、适于现场作业等特点，不少软质绝缘工具具有中国带电作业的独有特色。目前带电作业常用的绝缘绳主要有蚕丝绳、锦纶绳等，其中以蚕丝绳应用得最为普遍。
　　蚕丝在干燥状态时是良好的电气绝缘材料，电阻率约为1.5×1011～5×1011Ωcm,但随着吸湿程度的增加，电阻率将明显下降。由于蚕丝的丝胶具有亲水性及丝纤维具有多孔性，因而蚕丝具有很强的吸湿性，当蚕丝作为绝缘材料使用时，应特别注意避免受潮。
　　由于带电作业可能遇到突然起雾、下雪等恶劣气候条件，所以绝缘绳在潮湿状态下的电气性能将直接关系到人身及设备安全。据调查，我国带电作业中已多次发生绝缘绳湿闪及烧断事故，试验表明，绝缘绳受潮后，泄漏电流急剧增加，闪络电压显着降低，绳索发热甚至燃烧起火。
　　绝缘绳在高湿状态下的电气性能与材料的吸水性有关，当绝缘绳严重受潮时，水沿绳表面及内部孔隙形成连续的导电水膜，由于水膜具有离子电导作用，使泄漏电流大大增加，蚕丝绝缘绳的丝胶具有亲水性及丝纤维具有多孔性，因此水分子不仅附着绳表面及绳内间隙，而且渗透全部纤维内部，不仅使蚕丝绳的闪络电压明显降低，而且较大的泄漏电流导致绳索发热直至起火燃烧。
　　针对安全开展带电作业的需要，近年来，国内部分制造单位研制了防潮型绝缘绳。参照国外相关标准中对绝缘绳索的防水防潮要求，分别进行了168h持续高湿度下工频泄漏电流试验、浸水后工频泄漏电流试验、淋雨工频闪络电压试验。另外，为考核使用后的防潮性能，又增加了50%断裂负荷、漂洗、磨损后168h高湿度下工频泄漏电流试验。从试验结果来看，与常规型绝缘绳相比较，高湿度下工频泄漏电流显着减小，淋雨闪络电压大幅度提高，在浸水后仍可保持良好的绝缘性能。但需要指出的是：防潮型绝缘绳索在浸水、淋雨状态下有较好的绝缘性能，但这并不意味着绝缘绳索可直接用于雨天作业。防潮型绝缘绳索主要是为了解决常规型遇潮状态下绝缘性能急速下降的缺点，增强绝缘绳索在现场作业时遇潮、突然降雨等状况下的绝缘能力，从而提高带电作业的安全性。因此，无论哪一种绝缘绳索，应尽量在晴朗、干燥气候下使用。一旦遇到不良气候条件，防潮绝缘绳索的绝缘性能将优于常规型绝缘绳索。

Insulated tools for live working
Insulated tools for live working should have good electrical insulation properties, high mechanical strength , but also has a low moisture absorption , anti-aging benefits. In order to facilitate field operations , insulated tools should be light weight , easy to operate, easy to damage. Currently live working with insulated tools can be divided into hard and soft insulated tools insulated tools two categories. Rigid insulation tools mainly refers to the insulation tubes, rods , plates made ​​of insulating material based tool soft insulated tools based mainly refers to the insulating rope made ​​of insulating material tools. Direct impact on the performance of the insulation material and determine the electrical and mechanical performance tools .
1 insulating rod 
Glass fiber , epoxy resin and the coupling agent is the main component of the insulating rod. More insulated rod manufacturing method , which is mainly used in the manufacture of insulating rod craft wet volume , dry volume method, winding method and lead to pull method.
Aging of the overall aging of the insulating rod and some have two aspects of aging . Mainly refers to the whole wet aging , the aging time of the overall material ; part of aging mainly refers to the insulating rod at the top of the long-term strong electric field , due to local slip flash material , the drain discharge caused by aging. Especially for 500  kV live working tools, part of a strong electric field caused by the aging of the material , the tool decreases the overall insulation distance , easily formed accidents , should be regularly monitored way . Acceptance testing , the test voltage is too high will cause the streamer discharge , or corona , erosion by ion bombardment of the insulating material , the insulation destruction of chemical bonds electrons , resulting in deterioration of the organic material , resulting in a conductive sediments near the high end of the electrode District play to extend the field electrode , thereby leading to further deterioration of the material. Therefore , selecting the appropriate test voltage resistance test, the inspection is very important.
The state of the operating rod surface contamination flashover great influence on the performance of the operating rod. According to foreign test results show that the surface contamination , especially when the sediment conductivity and moisture resistance, flashover strength is severely reduced . This is because when the surface of the insulation rod and the atmosphere is dirty and the humidity is high, the voltage distribution along the insulating rod become more uniform, high field strength at the glow discharge will occur , so that the leakage current along the surface of the insulating rod having a transition characteristics. Live working abroad operating lever salt spray and artificial pollution tests to measure the salt spray , industrial smoke cohesion may affect sediment and dirt on the operating lever accident . The results showed that even at a low fog conductivity , leakage current is much larger than the perceived 1  mA current, the operating characteristics of the surface material of the rod , the longitudinal unevenness and other defects of the state of moisture and contamination flashover performance greater impact.
For decades, our live working materials and the production process of continuous improvement of the insulating rod . Stubbs molding process enhances the density and forming rod bending characteristics of the insulating material , the insulating material is greatly reduced water permeability , moisture resistance has also been significantly improved . Current product performance has reached international advanced level, some technical indicators even better than similar foreign products.
2 insulated wire 
Insulation rope is one of the widely used insulating material for live working , and can be used as vehicles, climbing tools, hanging rope , Paul安绳connected sets and so on. Insulated wire insulation parts made ​​based tool for soft insulated tools. Soft insulated tools with flexible, simple , easy to carry , suitable for field operations and other features , many soft insulated tool has a unique characteristic of Chinese live operations. Currently popular live working mainly silkworm insulating rope wire rope, nylon rope , which was the most common application of silkworm silk cord .
Silk is in the dry state a good electrically insulating material , a resistivity of about 1.5 × 1011 ~ 5 × 1011Ωcm, but with the degree of moisture increases, the resistivity decreased . Because silk sericin and silk fibers having a hydrophilic porous, and therefore has a strong hygroscopic silk , silk as an insulating material when used, should be especially careful to avoid moisture.
Because of live operations may encounter sudden fog, snow and other inclement weather conditions , so the rope electrical insulation properties in humid conditions will be directly related to the personal and equipment safety . According to the survey, China has repeatedly occurred in live working rope wet insulation and blown flash accident , tests showed that the insulation damp rope , a sharp increase in leakage current , flashover voltage decreased significantly from burning ropes on fire .
Insulated wire and electrical performance in absorbent material related to high humidity state , when the rope severely damp insulation , water surface and internal pores along the rope to form a continuous conductive film of water , because the water film with ion conductance effect, so that the leakage current is greatly increases, the insulating rope silk sericin or silk fibers having a hydrophilic porous, so only the water molecules and the surface of the rope in the rope attached to the gap , and the penetration of all the fibers and silk rope not only significantly reduce the flashover voltage , and relatively large leakage current lead rope heat until fire.
For jobs that require security to carry out live , in recent years , some domestic manufacturing unit developed a moisture-proof insulation rope . Referring to the international standards in the rope waterproof insulation requirements were carried out 168  h continuous high humidity getting off frequency leakage current test , after flooding frequency leakage current test , rain workers Flashover voltage test. In addition, moisture-proof performance appraisal after use , and increased by 50% breaking load , rinse , wear 168  h after getting off work frequency leakage currents and high humidity test . From the test results , compared with the conventional rope -type insulation , high humidity getting off frequency significantly reduce leakage current , a substantial increase rain flashover voltage , after flooding still maintain good insulation properties. It should be noted that : moisture-proof insulation rope flooding , better insulation properties under rain condition, but that does not mean that the rope can be used directly rainy insulation job . Moisture-proof insulation rope is mainly to solve the shortcomings of conventional type case tidal rapid decline of the state of insulation , reinforced insulation capability in case of influx of jobs in the field of insulation rope suddenly under rainfall conditions , thereby enhancing the security of live operations. Therefore, no matter what kind of insulation ropes , should be used in sunny , dry climates. The event of adverse weather conditions , moisture-proof insulation rope performance will be better than conventional insulation type insulation rope.