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1.
Considering the importance of 500 kV line and taking 500 kV transmission line in Chongqing as an example, the authors calculate lightning strike outage rate (including return stroke and lightning shielding failure) using regulation method, outage rate of return stroke using travelling wave method, and outage rate of lightning shielding failure using EGM. By comparing and analysing the calculating fesults, weakness of insulation and the area of easy to striking are found out, and corresponding improving measure is brought forward. The results show bigger gradient of lightning higher return stroke tripping, and in regulations result of accounting return stroke tripping is more closed to practical experience, accounting shielding failure rate exists obviously defect, and in EGM accounting shielding failure rate have take much factor, result is more close to practical experience. 相似文献
2.
This paper studies lightning protection performance of transmission line with high tower and great span, and puts forward the lightning shielding model of transmission line with high tower and great span. The model simulates the developing process of lightning downward leader, and take the effect of upward leader to downward leader into account. Moreover, the model consider backward lightning , that is even downward leader have developed lower than transmission line, Which will be occur lightning line. Aim at a certain sea transmission line with great span, its lightning performance is calculated with regular method, EGM and the model. The results have been analysed and compared. Because of thinking over backward lightning , the model can be used for calculating lightning shield performance of all kinds of transmission lines. 相似文献
3.
Analyze the Present Status in the Calculation Methods of Lightning Protection Performance for Transmission Line 总被引：1，自引：0，他引：1
Lightning is the main reason that endangers transmission line working safety and reliabilty today. The theory and characteristic of methods that not only estimate the lightning performance for back strike such as standard method, traveling wave method, Monte Carlo technique, treeing fault method, EMTP and so on but also for the shielding failure such as standard method, EGM, leader progression model and so on are summarized. The criterion of flashover for insulators is referred simply, furthermore, it gives the opinion that the development of research for the future. 相似文献
4.
Transmission lines are easily hit by lightning, and lightning shielding failure is an important reason of lightning accidents of transmission line. So researches on lightning shielding of transmission line should be strengthened. On the basis of the abundant understand to known lightning shielding models of transmission line, a new lightning shielding simulation model of transmission line is presented in the paper. In this model, the effect of attracting lightning of upward leader is considered reasonably, and the method of variable descending step is adopted to simulate the descending process of lightning leader. The simulation calculating results show that the model is in good agreement with field experience of transmission line. It can guide lightning shielding design of transmission line and estimate the performance of lightning shielding of transmission line. 相似文献
5.
The radiation field created by the transmission line stroked by lightning far from the lightning channel has been analyzed by the FDTD method.The authors we establish the calculation model and FDTD calculation method of transmission line,and discusses the import of lightning excitation source.The simulation of lightning stroked on a single transmission line in free space or stroked on three-phase high voltage transmission lines in actual environments has been done,and gives the distribution of transient radiation field around the transmission lines when lightning overvoltage wave transmits along the transmission line.The simulation result shows that: the effect of the transient radiation field caused by lightning over voltage wave done with environment is obvious,and the high frequency component of transient radiation field may disturb or do harm to the electronic facility or communication facility around the transmission lines. 相似文献
6.
Finite element method is applied to analyze the windage of suspension insulator strings under dynamic wind loads. The dynamic response of a suspension insulator string of 500 kV high voltage transmission line is numerically simulated with ABAQUS software, and results demonstrate that the windage angle of suspension insulator string is larger than that calculated by the conventional design code, which might be one of the main reasons of the frequently happened windage flashover accidents. 相似文献
7.
Installing compensation equipments is a good manner to improve line transmission capacity and maintain power system stability in the extra high voltage(EHV) long distance transmission line.It is of benefit to analysis and control by describing the effect of compensation equipment correctly.At present,for predigesting analysis or increasing real-time calculating speed,concentrated parameter circuit model is widely used to analyze 500 kV EHV long distance transmission line which may cause bigger error.So it is necessary to get a more reasonable model.On the basic of voltage and current distributed equations of even distributed long distance line,this paper deduces phasor diagram and power-angle character equations of uncompensated long line.Then the authors analyze the effect of compensators and define two characteristic parameters,namely,equivalent impedance x_(eq) and voltage coefficient K_V.Any compensating states of EHV long distance transmission line,example installing the compensators in the line or not or which type of compensators,is described by the general phasor diagram and power-angle characteristic equations.Furthermore,increment calculation(equations) of two characteristic parameters is presented by the compensator parameters which may make the concepts clear and predigests analysis easily. 相似文献
8.
雷电灾害事故分析有助于更好地掌握雷击途径和方式,认识雷电致灾规律,从而采取更有效的防护措施。针对2014年7月1日北京市密云县西田各庄镇某养殖场发生的雷电灾害事故,统计分析雷击时间段内该区域闪电定位资料;根据滚球法判断养殖场是否在直击雷保护范围内,计算牲畜位置处跨步电压和养殖棚雷电静电感应电压。通过逐项计算和分析,结果表明：牲畜遭旁侧闪络和接触电压致死。雷电的静电感应在金属棚上产生高电压,由于金属棚的支撑钢架结构未做接地,感应电荷释放通道不顺畅,与地面存在电位差,发生旁侧闪络,以及当牲畜接触到钢结构后,高电位通过牲畜向地面释放,致使牲畜死亡。最后提出了对应的防护措施和方法,减少或避免以后类似雷电灾害事故的发生。 相似文献
9.
Research on Lightning Intruded Wave for 500 kV Substations 总被引：1，自引：0，他引：1
The study on overvoltage for 500 kV substation caused by lightning intruded wave is presented. In this paper, we calculate by using electromagnetic transient program (EMTP) and combine substation with incoming lines ,so some influence factors can be considered such as impulse voltage second characteristic of insulator strings, lightning stroke point on the incoming lines and impulse grounding resistance of towers. The results show that the method is close to the practice and some factors of incoming lines are important to overvoltage. 相似文献
10.
In order to fully research the effects of external excitations, such as wind speed, wind direction and voltage disturbance, on a grid connected wind turbine with doubly fed induction generator, a co-simulation model of MW-class wind turbine system is established by using Simpack and Matlab/Simulink software. Also, by considering the actual control strategies in the process of simulation, the relationship between external excitations and mechanical system is studied. According to time-domain simulation under the turbulent wind condition, the dynamic meshing forces of gears are analyzed. Besides, the vibration responses of tower are calculated under the different external excitations. Research results lay a foundation for dynamic performance optimization and reliability design of a wind turbine. 相似文献
11.
Numerical models of typical 500 kV ultra high voltage (UHV) transmission lines are set up in ABAQUS/CAE software. The dynamic response of the transmission lines with different structure parameters under various ice shedding load cases are analyzed, and th 相似文献
12.
Considering that the transmission system of wind turbine works in complex and changing load environment caused by stochastic wind speed,this paper uses sparse least squares support vector machine(SL-SVM) to simulate wind speed of true wind field,and obtains time-varying wind load caused by stochastic wind speed. The lumped-parameter method is used to develop a dynamic model of planetary gear transmission system of wind turbine coupled with bearing. The model includes the varying wind load,time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing. The numerical method is used to simulate the dynamic performance of planetary gear system of Multibrid Technology Wind Turbine with 1.5 MW rated power. The vibration displacement responses of the transmission system are obtained as well as dynamic meshing force each pair of gear and nonlinear bearing forces. The research can provide a foundation for optimizing dynamic performance and reliable design of gear transmission system of wind generator. 相似文献
13.
电网发生大面积冰灾情况时,多条输电线路存在覆冰故障隐患,电网稳定运行受到严重威胁,需要提前制定输电线路融冰方案,合理安排融冰顺序。针对此问题,分析输电线路覆冰继续运行给电网带来的停电风险,将与待融冰输电线路相关联的变电站的电气主接线展开,将传统削负荷模型改进后应用于输电网与变电站主接线的组合网络,建立断路器可靠性模型,计算靠后融冰线路因继续运行的电网停电风险;利用计及风速及降雨影响的输电线路覆冰增长预测模型,计算输电线路的覆冰率,根据覆冰率门槛值确定待融冰线路集,基于覆冰严重度模型构建系统全局的覆冰指数指标;综合考虑电网停电风险及系统全局覆冰指数建立输电线路融冰紧迫度指标,动态更新待融冰线路并决策融冰顺序。最后,以IEEE RBTS系统进行算例分析,验证了所提方法的可行性与合理性。 相似文献
14.
To counteract capacitive current and resume power system, the neutral point of 35 kV power system at the mountainous area is grounding through the arc winding widely. In fact, there is great difficult in selecting the arc winding to satisfy the requirement of system. In a 35 kV power system which neutral point is grounding through the arc winding, the capacitance current are measured in site when a single-phase is grounding. From the measure data, the imbalance of three-phase voltage whether the arc winding exist or not and the operating situation of arc winding are discussed, and bring forward an attentive problem about operation of arc winding and decrease of lightning outage rates. 相似文献
15.
在对中国传统村落名录收录的古村落进行保护规划时,防雷保护是其中重要的一部分。现有的村落防雷保护研究更多侧重于定性的保护方法,对不同地形条件下的村落雷击概率的定量化研究还不多。本研究基于闪电随机模拟的方法,利用Matlab对闪电路径进行模拟,并分别分析村落位于平原、山脚及山谷处的雷击概率。模拟结果显示,平原的村落雷击概率最高,当村落位于山脚时,其雷击概率要比位于平原处小;当村落位于山谷时,其雷击概率比位于山脚处更小。主要原因是：建筑物周边的高大山体对于闪电有截收效应,位于山体周边时建筑雷击概率比平原时降低。模拟结果还显示小尺寸、低高度的建筑物仍然有发生侧击的危险,在农村的防雷保护工作中需加以关注。 相似文献
16.
在分析雷电直接击中建筑物导致物理损害的概率PB的影响因素的基础上,本文基于IEC62305推荐的不同防护等级的保护能力以及雷电流概率分布规律,推导出确定规范中LPL对应的PB因子优选值的一般过程。并针对推导过程完全依赖于规范推荐的防护等级及雷电活动特性,针对性差的特点,提出了根据建筑物直击雷防护实际情况以及项目所在位置雷电环境的统计特征确定PB因子的方法,该方法在一定程度上提高了PB因子选取的科学、准确性。同时,也对由于雷击物理过程复杂性、电气-几何模型的科学性、防护装置性能变化等使得PB因子取值中存在的问题进行了分析。 相似文献
17.
现代桥梁雷击灾害风险研究 总被引：2，自引：2，他引：0
开展雷击灾害风险评估,选取最合适的雷击灾害防御方案,是防止和减少因雷击桥梁产生灾害损失的重要手段,也是进行科学防雷的重要前提,借助安徽省气象局ADTD型闪电定位系统监测的2006—2013年逐日闪电数据,应用IEC 62305规范以及GB/T 21714国家标准,对安徽省马鞍山市长江大桥进行雷击灾害风险研究。结果表明：人身伤亡损失风险主要由直接雷击大桥导致的接触、跨步电压和物理损害引起;经济损失风险主要由直接雷击大桥导致的物理损害以及直接雷击和邻近雷击导致的大桥内部系统故障引起;比较大桥在无LPS、LPSⅢ和LPSⅡ三种设定方案下雷击灾害风险值,确定针对马鞍山长江大桥最优化的雷击防御方案二来降低人身伤亡损失风险和经济损失风险值。该风险评估部分成果在马鞍山长江大桥建设中得到实际应用,项目达到防雷要求并暂未出现雷击灾害事故。 相似文献
18.
The equivalent transmission line method is extended to multi-transverse electric modes of cavity which are introduced by aperture coupling, and it is used to analyze the shielding effectiveness of rectangular enclosures with apertures. The multimode transmission line method is verified by HFSS(High Frequency Structure Simulator). The results show that higher-order mode is essential to obtain an accurate shielding effectiveness of rectangular enclosure on wide frequency domain. Below the frequency of 1 GHz, nearer to the slot, the impact of higher-order mode on the shielding effectiveness is greater in the place mear the slot. Higher-order mode leads to a better shielding effectiveness. 相似文献
19.
为研究高压电晕电场生物效应物理机制,非均匀电场和电晕放电产生等离子体注入2种因素对种子的影响,利用频率为50 Hz,极距为4 cm,电压为0(ck)、4 kV、8 kV、12 kV、16 kV、19 kV的交流高压针-板电晕电场处理紫花苜蓿种子,通过1 mm厚的聚丙烯培养皿盖电介质阻挡和不加培养皿盖2组放电处理。培养后检测不同参数的高压电晕电场处理对紫花苜蓿种子生长的影响。结果表明:高压电晕电场处理紫花苜蓿种子时,无论是否有培养皿盖阻挡放电,均可改善紫花苜蓿种子的亲水性,使种子沉入培养皿底部,无培养皿盖阻挡放电组改善程度更大,除8 kV加盖阻挡组种子的吸水率比对照有所下降外,其余各组吸水率均上升。有无培养皿盖阻挡放电对紫花苜蓿种子的发芽势和发芽率有截然相反的影响,整个变化趋势呈非单调震荡型曲线,经培养皿盖阻挡放电后,可以非常有效的减小离子风对种子的物理刻蚀程度,同时降低紫花苜蓿种子接受的场强,并使紫花苜蓿种子接受的辐射电场更趋均匀。 相似文献
20.
为了剖析北京市雷击人身伤亡事故相关特征,根据1957—2015年北京市雷击人身伤亡事故资料,利用数理统计等方法分析了雷击伤亡相关特征。结果显示：有记录的雷击人身伤亡事故共65起,雷击死亡47人,受伤96人,人员伤亡比为2.04:1,平均每年伤亡2.42人。雷击伤亡事故在4—9月均有可能发生,主要在6—8月,其中7月最多（比例为32.31%）。雷击伤亡事故空间分布主要在北京市中部和东部,按区县统计东城区最多,与这里旅游场所较多、人员较为密集有一定关系。20世纪90年以后,雷击人身伤亡事故增长较多,且雷击伤亡事故郊区开始多于城区。雷击场所主要分布在开阔地带,所占比例43.08%,其次分别为建构筑物、树下、山上、农田、水域。雷击类型直接雷击最多,所占比例52.31%,其次分别为接触电压、旁侧闪络和跨步电压。长城和首都机场近些年发生雷击事故较多,需重点关注。同时利用1959—2012年雷暴日分布做了时间和空间对比,时间分布相对一致,空间分布有一定差异。最后根据雷击人身伤亡事故特征,研究提出一种方便安装、有效避雷的装置,以保护户外场所人员防雷安全。 相似文献