配电带电作业绝缘遮蔽工具的设计和应用

带电作业绝缘遮蔽工具的使用,可有效保障作业人员的安全。针对传统方法中存在安全性低、制作成本高及原材料提取工艺复杂等问题,提出配电带电作业绝缘遮蔽工具的设计和应用进行研究。采用防潮防水的树脂、聚乙烯薄膜、天然乳胶等材料分别对绝缘遮蔽罩、绝缘服、绝缘手套、绝缘靴和绝缘毯等常用配电带电作业绝缘遮蔽工具进行设计分析。利用环氧树脂绝缘板对绝缘隔离挡板、跌落式熔断器的上侧和下侧引线绝缘支架等配电带电作业绝缘遮蔽工具进行优化。将实验结果与传统带电作业方法进行时,结果表明,文中设计的工具实用性更好,在 作业过程中对配电无影响,具有很好的应用前景。     

10kV配电线路带电作业导线遮蔽罩温升特性分析

导线遮蔽罩作为绝缘遮蔽用具已广泛运用于10kV配电线路带电作业中,但遮蔽罩过热会影响其绝缘性能,威胁工作人员安全。利用有限体积法建立了导线遮蔽罩温度-流体场计算模型,研究了导线载流量、风速和日照强度等对软、硬质导线遮蔽罩温升的影响。结果表明,额定负荷条件下,软、硬质遮蔽罩的最大温升分别为19.1、17.5K,硬质遮蔽罩的散热效果较好;导线遮蔽罩温升随负荷电流的增加呈指数规律增大,随环境风速的增加而下降,但下降幅度逐渐减小,日照强度是导线遮蔽罩温度过高的主要因素之一。     

10 kV配电线路带电作业遮蔽用具—绝缘毯温升特性分析

10 kV配电线路带电作业过程中,为避免作业人员发生触电事故,需采用绝缘毯等绝缘遮蔽用具对带电体进行包裹遮蔽。通过温度—流体场耦合方法模拟了10 kV配电线路带电作业时绝缘毯的温升和散热过程,分析了绝缘毯的材料、长度、厚度、风速和日照强度等对绝缘毯温度分布的影响。结果表明,相同条件下,树脂绝缘毯的温升低于橡胶绝缘毯;绝缘毯包裹厚度的减小和风速的增大对绝缘毯的散热具有一定的促进作用;日照强度升高100 W/m2时,橡胶和树脂绝缘毯的温度分别升高0.9、0.8 K左右,日照是绝缘毯温度过高的主要因素之一;虽然树脂绝缘毯的散热性能更好,但其熔点较低,在高温重负荷环境下应避免树脂绝缘毯的温度过高。     

带电作业用绝缘遮蔽用具组合沿面放电试验研究

在配网带电作业中,为了提高绝缘防护面积,常将多个绝缘遮蔽用具组合使用,此时不同遮蔽用具之间的重叠部分就成为绝缘防护的薄弱区域。针对几种常用的绝缘遮蔽用具开展了组合使用时的沿面放电试验,采用球-棒电极模拟现场作业工况,并使用高速摄像机观察放电路径。结果表明,绝缘遮蔽用具的材料类型对其沿面绝缘性能影响较大,橡胶类和塑料类遮蔽用具的沿面绝缘性能接近,树脂类遮蔽用具的沿面绝缘性能较低;树脂绝缘毯在组合使用时,重叠部位贴合更加紧密;当重叠长度为15cm时,树脂绝缘毯重叠区域的沿面放电电压与橡胶毯接近;考虑10kV配网线路最大工频电压为24kV时,绝缘遮蔽用具组合使用时的重叠部位的长度不小于15cm。     

配电线路带电拆搭作业使用绝缘竖梯

带电拆搭引线作业采用绝缘竖梯,解决了作业现场无法使用绝缘高架车进行带电作业的难题,为带电作业增添了新的工器具。叙述了10kV配电网带电作业中,自行研发的绝缘竖梯的技术参数、开发过程及利用绝缘竖梯进行带电拆搭10kV熔丝具上引线、10kV支接、耐张杆引线等作业的操作要点和技术管理要求。由于使用绝缘竖梯,研究费用投入少,产出高,在满足带电作业规程要求的前提下,可以缩短线路故障的抢修时间,提高供电可用率和经济效益,被推广应用。     

66kV交流输电线路下相导线绝缘斗臂车带电作业研究

为确保66kV交流输电线路下相导线绝缘斗臂车带电作业的安全性,并进一步提高带电作业的工作效率,主要从带电作业时的安全距离、绝缘斗臂车的绝缘性能能否满足相关要求两方面进行分析并开展了绝缘上臂及整车泄漏电流试验、绝缘上臂交流耐压试验、绝缘模拟人绝缘泄漏试验,结果表明,在额定线电压下绝缘上臂和整车泄漏电流最大值分别为60.7、65.0μA,满足规程要求;作业人员穿戴全套屏蔽服接触带电模拟导线的实操试验中无任何不适感。可见使用配网绝缘斗臂车为66kV交流输电线路下相导线开展带电作业是可行的。     

带电清除配电线路异物的遥控仿生操作工具

针对清除中压配电线路异物使用传统绝缘工具不能满足带电作业的状况,研发了一种遥控仿生操作工具。该工具由机械端部、绝缘杆、遥控发射器和接收机组成。在带电清除异物时,只需将遥控仿生操作工具的端部放在合适位置,即可方便地实现抓取、拽拉或剪断异物的操作,整个操作过程施力准确,减少了端部机构的抖动,确保了人体与带电体间的有效空气间隙,保证了操作工具的有效绝缘距离,降低了流经人体的泄漏电流,减少了带电作业时间,提高了中压配电线路带电清除异物作业的安全性及工作效率。     

绝缘斗臂车短杆作业法配网带电作业技术应用研究

绝缘斗臂车短杆作业法是以绝缘斗臂车的绝缘斗为作业平台,结合绝缘手套、操作杆等作业工具来实现带电作业,与绝缘手套作业法区别在于增加了绝缘短杆作业工器具,等同于增加了绝缘电阻和安全距离,提高了作业安全系数。鉴于厦门地区10kV配网线路的杆型和线路分布方式,本文分析了常规作业法与新型绝缘斗臂车短杆作业法,在10kV配网带电作业的断、接引流线项目中应用的优劣势,为后续同杆型作业提供作业参考。     

新型全绝缘熔断器在配电变压器中的应用

新型全绝缘高压喷射式熔断器是广泛应用在10kV架空配电开关柜的保护和开关设备,目前广泛采用的跌落式熔断器具有触头裸露、绝缘水平低、拉合操作有一定危险性等弊端,基于此,研发了适用于国内要求的熔断器,将绝缘防护性能和操作安全性均较常规的熔断器进行了较大改进,并按国内要求大幅提高了开断能力和耐压水平,可以拉合负荷电流,结合实际要求提出了全面的试验标准,并成功地通过了试验挂网运行。     

10kV配电线路转角杆中相引线绝缘挡板的研制

在带电断、接转角杆中相引线作业过程中,应对带电部位和地电位设备做绝缘遮蔽处理,但转角杆中相导线断、接位置的特殊性,导致现有的绝缘遮蔽流程复杂、作业时间长。研制的一种新型的适用于转角杆中相引线的绝缘挡板。该绝缘挡板由电杆绝缘挡板和横担绝缘挡板组成,经过加工、打磨及装配,完成样品的制作;并进行电气试验和机械试验,试验结果表明绝缘挡板样品满足带电作业要求。介绍了在推广应用的过程中,绝缘挡板的使用所带来的经济效益、安全效益和社会效益。     

冷藏集装箱保温涂层经济厚度的计算和绝热性能的分析

对冷藏集装箱添加保温层的经济厚度做了分析,推导出计算公式,并对其节能效果通过实例做分析比较。选择合适的绝热材料和合理的经济厚度,加上正确的施工工艺,可以提高冷藏集装箱的保温性能,获得可观的经济效益。     

Characterization of the insulation and leakage currents of PV generators: Relevance for human safety

Protection against electric shock in photovoltaic generators (PVGs) with active protective measures requires an in-depth knowledge of the electrical behaviour of PVG insulation and PVG response under operating conditions with insulation faults. On the one hand, this knowledge can be obtained with an equivalent circuit model that characterises this insulation. The model presented can be used to: (i) evaluate PVG insulation resistance and leakage current; (ii) analyse potential hazards for the general public; (iii) design the best means of protection. On the other hand, this article also describes the insulation of a functioning PVG, and its reaction to meteorological variables (MVs) in laboratory and field conditions. Test results highlight those MVs that have a greater influence on PVG insulation as well as the relation between weather and insulation. This type of characterization is crucial when it comes to testing the operating capacity of the protective devices used in active protective measures against electric shock under different meteorological conditions.     

Method of synthetic constraint,Fermat’s principle and the constructal law in the fundamental principle of conductive heat transport

This article documents the method of synthetic constraint, a physical principle, to be applicable in the fundamental methodology of conductive heat flow, in replacement of calculus of variations and other optimal control theories. In particular, the optimum distribution of limited volume of insulating material on one side of a plane wall as well as cylindrically curved surface is obtained when the amount of insulating material is noninfluential to the imposed exponential temperature profile. The same physical theory is exercised for a generalized case of a stream suspended in an environment of different temperature and where the exponential wall temperature distribution is affected by the amount of insulation added. The result obtained conforms to those existing in open literature. Further from the physics of the problem it has been argued that a minimum exists for such class of problems of heat transfer from an insulated wall. Finally, it has been synthesized that Schmidt’s criterion for the fin design, the tangent law of conductive heat transport and Fermat’s principle in geometrical optics are but special stipulations of the method of synthetic constraint, which in turn is a corollary of constructal law. Thus the basis for analogies among physical theories is sought. The fundamental solution exhibits a category of equipartition principle.     

水轮发电机转子磁极绝缘降低的故障分析及处理

针对广东粤电新丰江发电公司1号水轮发电机转子磁极绝缘电阻一直偏低的问题．从制造安装质量、绝缘老化程度、检修工艺过程以及运行与维护等几个方面进行了认真具体地分析,总结出了引起1号水轮发电机转子磁极绝缘电阻降低的原因,并提出了彻底解决1号水轮发电机转子磁极绝缘电阻偏低问题的方法以及有效提高水轮发电机转子磁极绝缘电阻的改进措施。     

供热管道保温材料的选择及经济保温层厚度计算

合理选择供热管道的保温材料及经济保温层厚度,对减少管道在输送热媒过程中的散热损失,降低工程造价尤为重要。本文根据国家现行标准和有关规定,对热网保温材料的选择、经济保温层厚度的简便计算方法进行了阐述。为工程实践中在管道保温方面,达到节能降耗,节约投资的目的提供参考。     

Collector cum storage solar water heaters with and without transparent insulation material

The integrated collector–storage solar water heaters are less expensive and can offer the best alternative for domestic applications particularly to small families to meet hot water requirements. The top heat losses of such solar water heaters are quite high during the night and the temperature of stored hot water is considerably reduced unless covered with extra insulating cover in the evening which is a cumbersome job. The transparent insulation material widely used in Europe for space heating can also minimize top heat losses, if used in such solar water heaters. For this purpose, two units of solar collector cum storage water heaters have been designed to study the relative effect of TI for retaining solar heated hot water for a night duration. Both units were identical in all respects except one of them was covered with TIM. The theoretical exercise was carried out to evaluate design parameters of ISC which revealed total heat loss factor (U_L) 1.03 W/m² K with TIM glazed against 7.06 W/m² K with glass glazed. The TIM glazed has been found to be quite effective as compared to glass glazed SWH and yielded hot water at higher temperature by 8.5 to 9.5°C the next morning. The storage efficiency of such solar water heaters has been found to be 39.8% with TIM glazed as compared to 15.1% without TIM. The TIM glazing means not having to cover the ISC solar water heater with a separate insulator cover in the evening and thus makes its operation much simpler.     

不同外墙保温方式对墙体热工性能的影响及分析

通过对墙体的温度分布及内表面温度的分析和计算,对比分析了外保温与内保温两种外墙保温方式。研究表明外墙外保温方式在提高室内舒适度、减少墙体开裂、消除热桥影响及降低能耗等方面优于内保温方式。