【作者】 毕茂强；

【导师】 蒋兴良；

【作者基本信息】 重庆大学 ， 电气工程， 2013， 博士

【摘要】 输电线路覆冰灾害是威胁电网安全运行最为严重的自然灾害之一。近年来，受全球气候变暖影响，各类极端天气、气候事件频发，当寒冷空气持续来袭时，架空输电线路不可避免的会出现覆冰灾害。输电线路覆冰灾害将导致严重损失，可能造成输电线路过荷载、导线舞动、线路大面积的覆冰倒塔、绝缘子串覆冰闪络等事故，破坏电网结构，威胁电网安全，甚至使电网瘫痪。因输电线路覆冰灾害发生时往往天气恶劣、冰雪封山交通受阻、通信中断、抢修困难，因而经常造成系统长时间停电，给工农业生产和国民经济造成严重损失，影响人民的日常生活。国内外对输电线路覆冰问题进行了长期而广泛的研究并提出了30余种防冰、除冰方法，但是采用电流焦耳热的防冰、除冰方法来应对输电线路覆冰仍是目前最为快速和有效的方法之一。现有的电流的防冰、除冰方法在实施过程中需要融冰导线退出运行，不仅会给电网和社会带来经济损失，还有可能威胁到电力系统的安全运行。随着社会对供电可靠性、安全性要求的提高和智能电网的发展需求，开发一种不断电、实时的除冰方法具有重要意义。鉴于高压输电线路多采用分裂导线，本文根据输电线路分裂导线结构特点，提出了一种不需要断电即能实施的除冰方法即分裂导线电流转移循环融冰方法，详细阐述了其基本原理和实施步骤，并从覆冰导线临界融冰电流密度角度论证了该方法的可行性。同时以六分裂导线为例计算融冰实施过程中，线路电感的变化和通与未通流子导线间的电压差。计算结果表明该电压差与导线传输的负荷电流大小、选择的融冰方式和距离短路点的距离有关。为减少子导线间绝缘间隔棒和控制开关断口处的电压，需控制融冰段长度。通过覆冰条件下覆冰导线的热平衡分析，本文建立了覆冰条件下覆冰导线电流融冰模型，并利用有限元仿真软件对模型进行了仿真研究。通过对模型的简化分析，提出了覆冰条件下覆冰导线融冰时间的简化计算公式。根据分裂导线电流转移融冰方法的控制要求和融冰时间简化计算公式对分裂导线子导线分组进行初步设计。在人工气候室和自然覆冰站进行了大量电流融冰试验，人工气候室试验结果表明，覆冰条件下覆冰导线临界融冰电流计算结果和电流融冰仿真结果与试验结果基本一致，同时还验证了分裂导线电流转移融冰分组设计方法的有效性。自然覆冰试验站现场试验结果表明，采用分裂导线电流转移循环融冰的方法对导线进行分组融冰可有效去除去分裂导线上的覆冰；在现场融冰试验中覆冰导线的脱冰时间具有一定的分散性，且出现了脱冰跳跃现象，脱冰跳跃的幅度与覆冰厚度有关，为限制脱落跳跃幅度需在覆冰达到一定程度后便进行导线融冰。通过对人工气候室和自然覆冰站的融冰试验结果和融冰试验过程的分析，提出了基于多种参数的分裂导线电流转移循环融冰模糊控制方法，并对该方法的输入变量、输出结果、模糊隶属度函数以及模糊规则进行了初步的设计。更多还原

【Abstract】 Icing disaster taken place on transmission line is one of the most serious problemscompared with other natural disaster. In recent years, because of the global climatewarming, kinds of extreme weather were taken place frequently. When continuouscold-air were outbreak, the formation of icing on the outdoor transmission line isinevitable. The icing disaster will cause serious losses, such as overloading, conductorgalloping, tower collapsing, and insulator string flashover accident. It will not onlydamage the grid structure, but also threat to the security of the gird, even failures of thegrid. When the icing disasters were happened, they are always accompanied withinclement weather. Therefore, traffic blocked by the snow and communication was alsodisrupted. So that it is very difficult to repair the damaged power grid, thus resulting inextended power outage, causing serious losses to industrial and agricultural production,affecting the daily life of the people and to the national economy caused huge losses.There are more than30anti-icing and de-icing methods reported in home and abroad.But the de-icing method which used the Joule heating of the current is the fastest andmost effective de-icing method. However, many methods of these kinds are carried outwhen the transmission line is outage. The outage will bring economic losses, reducingthe safety factor of the gird, but also causing great inconvenience to peoples’ living.With the increase requirement of safe reliability of the gird and developing of smart grid,in order to ensure the safe and reliable operation of the power system, the developmentof an uninterruptible, real-time anti-icing and de-icing method is of great significance.Because of the bundled conductors are widely used in HV and EHV transmission,the paper propose a novel, uninterruptible, and real-time de-icing methods, i.e.icing-melting method by channel load current of bundled conductor into sub-conductorscircularly(IMCLC), based on the special structure of bundled conductors. Thefundamental principle and control scheme of this method were represented in detail.Based on the six-bundled conductor, this paper calculated electrical inductance atdifferent condition and the voltage difference between sub-conductors with and withoutcurrent. The calculated results reveal that this voltage difference corresponding to theload current, ice-melting model and the distance far away from the short point. In orderto reduce the voltage on the insulation spacer and the switch, the ice-melting distance ofconductor should be reduced. Through the analysis of thermal balance of icing conductor, this paper establishedthe critical ice-melting model and current ice-melting model, and their impact factorswere also studied. At the same time, the COMSOL Multiphysics was used to simulatethis model. The simplified calculation formula of ice-melting time was proposed bysimplifying this current ice-melting model. According to the control demand of IMCLCand the simplified ice-melting time, the grouping method of the sun-conductor wasdesigned.Many ice-melting experiments were carried out in the artificial climate chamberand the natural icing test station. The test results reveal that the calculated results ofcritical ice-melting current and simulated results were in a line with test results, thegrouping method of sub-conductor was also be examine to be correct. The fieldice-melting test show that the ice layer on the conductor can be removed effectively byusing the IMCLC method, the ice-melting time is dispersed, and the jumping caused bythe ice shedding will generate huge displacement of the conductor which affected by theamount of ice layer on the conductor. Therefore, the ice-melting work should be carriedout when the ice thickness reach a threshold to limit the jumping magnitude.Based on the test results in the artificial climate chamber and field test at thenatural icing station, this paper proposed a Fuzzy Expert control method of CMCLCwhich based on multiple parameters. The input and output parameter, membershipfunction, and fuzzy rules were also designed.更多还原