飞机防冰涂料的研究进展

介绍了防冰涂料的机理以及国内外防冰涂料的研究进展,包括低表面能、形成粗糙表面结构的超疏水涂层,同时分析了将防冰涂料与热除冰技术联合使用的可行性,讨论了防冰涂料应用存在的问题,对防冰涂料的发展趋势进行了分析和展望。     

特高压直流输电系统换流站的优化设计(英文)

Based on the consultation and study for Xiangjiaba-Shanghai ±800 kV UHVDC(ultra high voltage direct current) project,this paper presents an optimal design for key technique solutions.In this paper,the DC system electrical scheme design,the DC filter design,the DC harmonic component suppression,the over voltage and insulation coordination,the requirements for converter station equipment,the main equipment technical parameters of equipment(including thyristor valve,converter transformer,smoothing reactor,DC breaker),the configuration of measuring device and DC control protection system,and the de-icing operation design are investigated.According to the UHVDC technology researched conclusions and the development of the project construction,the UHVDC system design for converter stations becomes an optimal combination.The optimized design solves numbers of technical problems of the world’s first UHVDC project,and it is applied to the project’s construction.Under the actual operating condition,the optimized design is proved to be correct and superior.These optimal design conclusions are impartment for developing UHVDC technique and equipment,and provide reference for future UHVDC projects.     

基于高频高压激励法的输电线路融冰方法研究

针对现有输电线路融冰技术的缺陷,提出了一种基于线路集肤效应和电介质损耗理论的18kV、40 kHz高频高压激励融冰方法.该方法通过提高线路融冰电流的频率来加深线路的集肤效应,使线路单位长度的电阻显著提高,即在相同的发热功率要求下可减少线路的传输电流.简要论述了除冰装置的具体构成及其线路连接运行图.根据1000 kV特高...     

贵州电网融冰方法的研究和应用

对2011年冰灾中贵州电网在110 kV及以下输电线路采取的融冰方法进行了总结,分析了各种方法的应用范围,比较其优缺点。基于贵州电网的实践,提出主要采用车载直流融冰装置和融冰变压器两种措施进行110 kV及以下输电线路融冰,并完成了相应样机的研制。现场试验证明了所提措施的可行性。     

输电线路中频融冰频率与热功率均匀度分析

输电线路的覆冰会引发线路过负载、绝缘性能降低、杆塔倒塌、导线舞动等事故,而主流的短路融冰方法都存在着不可克服的缺陷;为此在高频激励新型输电线路融冰方法基础上,针对其在冰层介质损耗角正切值较小时电源频率过高的问题,提出了以牺牲一定融冰热功率均匀度为代价的中频融冰方法。首先基于均匀传输线理论,以长为100 km、电压等级为220 kV输电线路为例,搭建覆冰线路均匀传输线等效电路模型;继而分析沿线电压、电流和功率因数分布规律以及融冰频率与热功率均匀度的相互影响;最后提出输电线路中频融冰最佳电源频率的确定方法。仿真结果验证了所提方法的有效性与实用性。     

Corrosion behaviour of aircraft coating systems in acetate- and formate-based de-icing chemicals

Corrosion behaviour of four coating systems, which are commonly used in aircraft components; namely cadmium-coated and subsequently chromate-treated steel AISI 4340, aluminium-coated steel AISI 4340, anodised aluminium alloy 7075-T6 and chromate-treated aluminium alloy 7075-T6, were investigated in six commercial acetate- and formate-based de-icing chemicals. The results show that the aluminium-coated steel specimens experience least corrosion among the four coating systems; no corrosion is detected in potassium acetate-based de-icing chemicals (Safeway KA HOT, Safegrip and Safegrip+), although some corrosion is observed in the other three chemicals (Safeway SD, Safeway SF and Meltium). In contrast, the coatings in the other three coating systems are damaged in all six de-icing chemicals. The thickness of the coating does not necessarily predict how well the coating will protect the substrate; the thickest coating, several tens of micrometres, is apparent on the cadmium- and chromate-coated steel specimens, while only a few micrometres thin aluminium coating on the steel substrate is the only coating system that can survive the corrosion tests in some of the de-icing chemicals. Comparison of the results from the two test methods used in this research, polarisation measurements and chemical exposure tests, shows that, for each coating system, the extent of corrosion, as evaluated on the basis of weight changes calculated from corrosion current density values and those experienced during chemical exposure tests, is different: the weight changes that materialise during exposure tests are, at least, from one to two orders of magnitude higher than those predicted by calculations. In this paper, these observations are discussed and explanations for them are presented.     

冰雪灾害条件下我国电网安全运行面临的问题

论述了防止复杂大电网发生冰灾事故的各个环节，介绍了研究现状和存在的问题，指出了在冰雪灾害条件下我国复杂大电网安全运行需要加强研究的8个关键问题：覆冰机理、覆冰外绝缘故障机理、有效的防冰、除冰方法、大电网覆冰在线监测与诊断方法、覆冰线路灾害局部化设计、电网覆冰在线评估、预警与决策以及建立复杂大电网覆冰灾害应急处理体系，并提出了可能的解决方法。     

风力机桨叶超声波除冰实验技术研究及其应用

利用人工环境实验室、模态分析系统、自行设计的两套超声波除冰设备和嵌有压电陶瓷片的风力机桨叶建立风力机桨叶超声波除冰实验台,对不同覆冰状态下的桨叶进行了模态分析,从桨叶的曲率模态参数中提取风力机桨叶覆冰区域与覆冰厚度参数,并利用压电陶瓷片产生的超声波横向剪切应力给风力机桨叶除冰。实验表明,根据所获得的覆冰区域与覆冰厚度参数能较准确地诊断风力机桨叶覆冰状态,超声波除冰技术适用于风力机覆冰桨叶。通过对实验数据分析,提出了除冰时间与覆冰厚度、除冰能耗与覆冰温度和除冰能耗与覆冰厚度之间的定量关系式,为设计超声波桨叶除冰系统提供实验依据。     

青藏直流联网工程大负荷试验策略研究

分析比较了直流输电工程大负荷试验的双极运行模式、背靠背模式、融冰模式的优缺点,针对藏中电网"大直流、小电网和弱受端"的特点,指出在目前条件下采用融冰模式是青藏直流比较可行的大负荷试验运行方式。结合此种运行方式,分析了在大负荷试验期间正送极或反送极单极闭锁,一极功率因其他原因导致变化而对藏中电网的频率稳定带来的影响,提出了正送极快速功率回降以及联切非故障极的控制策略,同时针对直流系统的这种控制保护策略提出了安稳系统的切机切负荷策略,2种策略相互配合可以有效保证藏中电网的安全。最后通过仿真系统验证了所提控制策略的有效性。     

基于加权平均组合评价法的电网直流融冰计划决策

电网在遭受大范围冰雪凝冻灾害时如何编制合理的输电线路直流融冰的计划成为调度人员迫切需要解决的问题,为此提出了输电线路直流融冰排序评价指标来识别线路融冰的紧急性。该指标以线路重要性、实时覆冰率和预测覆冰增长率为属性因子,用加权平均组合评价法确定各属性因子的权重。在此基础上结合线路直流融冰的特性提出了输电网络直流融冰计划决策方法,在约束条件下能优先安排亟需融冰的线路。贵州电网的应用实例验证了该方法的有效性和可行性,可为电网的抗冰工作提供参考借鉴。