Lightning Protection Performance of Transmission Line with High Tower and Great Span

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.     

Analysis on the Lightning Protection Performance of 500 kV Double-circuit Transmission Line

Using double-circuit transmission line is the developing tide for main 500 kV configuration to reduce line holding ground, so analyzing it's lightning protection performance is important to extend double-circuit transmission line in ultra high voltage network. The lightning protection performance of 500 kV double-circuit transmission line is studied with EMTP and EGM. The statistical method is applied to analyzing the lightning protection performance of back stroke by considering the randomness of working voltage's phase when lightning stroked the top tower. The result is that the line lightning protection level is different when the working voltage of conductor is different. It also improved the EGM by considering the effect of wind speed when analyzing the lightning protection performance of shielding failure. Furthermore, the results are given that wind speed has effects on the protection angle and the rate of shielding failure by using the program to calculate it.     

Lightning Proof Performance of 500 kV Transmission Line in Chongqing Area

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.     

Model and Numerical Analysis of Radiation Field Created by Lightning Overvoltage Wave on Transmission Lines

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.     

Computerized Simulation of the Transmission Line in High-speed PCB

With the rapid development in logic circuit,the effect of transmission line in PCB becomes a confined factor.In the design of high-speed PCB,the factors which affect the integrity of signal can be found by computerized simulation of the transmission line,simultaneously the signal quality could be optimized.The capacitance matrices of transmission line in high-speed PCB have been computed with this method that is the total charge Green's functions with method of matrix,then the time-domain model is built.Connected to IBIS model of the I/O buffer these models can be used in computerized simulation of the transmission line.The result of simulation is equal with the result produced by EDA software-Specctraquest of cadence Co.and the efficiency of simulation is advanced.     

Analyze the Present Status in the Calculation Methods of Lightning Protection Performance for Transmission Line

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.     

A Numerical Method for Transmission Line Equations

Transient analysis of transmission line has recently been received more attention because operating speeds in high-speed digital electronics are increasing. Transmission line equations are hyperbolic partial differential equations, firstly this paper deduces how to change transmission line equations into quasilinear differential equations , thus the transmission line equation numerical result is gotten by computing the differential formation of quasilinear differential equations. The constraint of voltage and current is be considered and lumped equivalent circuit mode at boundary network collaborated at the same time in finding boundary conditions. Finally the paper computes transient response of transmission line with two typical boundary conditions. Numerical result shows that this approach is an effective way. It is explicit algorithm with less CPU consumption which can get time field response directly. The agree-upon effective way does be frequency field method, however it could not get time response unless the numerical inverse laplace transformation (NILT) be introduced. Thus this approach is more effective than FFT algorithm.     

地形对于村落雷击概率影响模拟研究

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。     

Development of a Novel Intellectual Transmission Line Inspection System

The power transmission line is one of the important parts of electrical power system,the management and inspection of the transmission lines have been significant routine job ensuring the reliability of the transmission system. This paper describes in detail the basic principle of the intellectual transmission line inspection system using Geographic Information System(GIS) and Global Position System(GPS) technology.This novel inspection system is composed of pocket PC,GPS receiver and management PC,and takes full advantage of modern computer and network communication technique.Owing to the advantages of high reliability,practicability and scalability,the practical application of this intellectual inspection system shows that it completely meets the requirements for fast speed,high efficiency and real-time performance.     

Power Model of Bond Graph and Dynamic Simulation of Hoist System for Multi-Flow Transmission

The double drive hoist reducer developed in the planetary gear is a new generation of energy saving and environment protecting hoist product. The multi flow transmission system theory of hoist is analyzed. With the theory and method of bond graph,a bond graph model with coupled vibration is established for hoist multi flow transmission system for the first time. The state equation of the system is developed and dynamic simulation analysis is also carried out. The internal changing law and relationship of the system for the state variable are got. Therefore, the dynamic properties and gearing features of this system are revealed comprehensively. The research results can provide the dynamic analysis method and design basis for multi flow transmission system of hoist.     

基于层次分析模型的云南省雷电致灾评价及易损性区划

根据2008—2017 年闪电定位监测和雷电灾害统计资料,分析地闪活动的时空分布规律,建立包含雷电风险、地域风险和承灾体风险的雷灾易损性综合评价指标体系,运用层次分析法(AHP)构建指标权重判断矩阵,得出易损性综合评价指数R 的换算方程并确定各州（市）雷灾易损性等级,形成云南省雷电灾害易损性风险区划。结果表明：昆明、玉溪地闪致灾因子活跃,雷灾易损性综合评价指数高,是雷电灾害极高易损区,受灾涉及行业及影响范围广;普洱、曲靖、丽江、楚雄、红河、西双版纳为雷电灾害高易损区,该等级区域所占比例最大,分布范围最广;保山、昭通、临沧、文山、大理为雷电灾害中易损区;迪庆、怒江、德宏为雷电灾害低易损区,通过加强雷电防御设施建设,扩大预警覆盖面,强化防雷科普宣传能够提高承灾体抵御雷击的能力。     

FDTD Method''s Application in the Research of Television Interference From High Voltage Transmission Line

The mechanism of television interference is discussed from High voltage transmission line. Then the computational model is established, and scattering fields are calculated with the finite-difference time-domain(FDTD) method, and the results are visualized. The scattering effects of High voltage transmission lines on horizontal polarization waves (corresponding to TM mode) are greater than on vertical polarization waves (corresponding to TE mode).     

Simulation of the Dynamic Performance of CHANASTAR Minicar with Automatic Transmission

According to the AT minicar project of Changan Automobile CO.Ltd.,the system for simulating the dynamic driving mode of the powertrain with Automatic Transmission is established.The engine and hydraulic torque converter are tested,and the character diagrams are protracted.The two parameter shift rule and the driver fuzzy control module are established.On the basis of dynamical equation,the kinetic model of car is established.With the system,the dynamic and economical performances and ten-mode driving status are simulated.The simulation results show that the system can simulate the actual driving status well,the dynamic and economical performances of the minicar basically meet the technical requirements.The theoretic foundation is provided to the project.The foundation of cruise control is constituted.     

Modeling by Bond Graph and Simulation for a Metal Pushing Belt Continuously Variable Transmission System

Continuously variable transmission is the ideal transmission mode, the Metal Pushing Continuously Variable Transmission (CVT) is the most mature CVT used in vehicle at present. By studying the transmission mechanism and ratio change characteristics of Metal Pushing Continuously Variable Transmission system, and using the bond graph theory, a bond graph model of continuously variable transmission is established in this paper, and the state space function is derived. Based on the model, The simulation of transmission characteristics of a CVT car is studied, the simulation result shows that the dynamic characteristics of continuously variable transmission could be expressed in this model. The research results can provide the theoretical analysis method and design basis for CVT vehicle.[WT5HZ]     

Method and Analysis of Time Series Model for Transmission Error

This paper presents the time series model of gear drivetrain error and a compari-son amang several typical time series spectrum estimations.and suggests a time series model suitablefor discribing transmission error.     

Modeling and Simulation Analysis of the Electromechanical Coupling Facts about Precision Transmission System

Electro-mechanical coupling facts about transmission system influence dynamic characteristic and response characteristic of servo system. The coupling factors of precision transmission system are put forward, and the modelling methods of electro-mechanical system are analyzed. Based on the large-scale precise horizontal machining center, the dynamic chart of servo feed system is gained through analyzing mathematical model of the taehes, and the influence on transmission stiffness and transmission error is simulated in precision transmission system. Through changing parameters in servo feed system, the influence on dynamic characteristic and response characteristic is analyzed, so it provides a mathematical model for parameter optimization.     

COTGROW：棉花生长发育模拟模型

ＣＯＴＧＲＯＷ模型是应用作物模型的理论和方法，借鉴国外同类模型的经验，在多年田间试验研究的基础上，根据中国棉花生产管理的实际，研制完成的一个融棉花生长发育与产量形成及常规栽培管理为一体的动态模拟模型。该模型的核心部分由碳素平衡、发育与形态发生、水分平衡、氨六平衡、栽培措施和输入与输出等模块构成，可根据土壤和气候数据模拟播种期、密度、地膜覆盖、去早蕾、打顶、喷缩节安、喷乙烯利、灌溉和施肥等单个或组合措施条件下的棉花生长发育、产量和品质形成，还可模拟２ｍ上层内各上层的土壤水分状况、氮素状况及植株各部分的含氮量和最终棉株对氮、磷、钾的吸收量。利用模型模拟不同栽培措施对棉花产量的影响结果表明，各种措施的产量拟合指数都在０．８５以上；模拟安阳１９８５年至１９９４年不同气候条件下的产量也具有很好的一致性。但模型还需要在其他类型气候和土壤条件下进行检验。     

Analysis of a multimode transmission line model of the shielding effectiveness of enclosures with apertures

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.     

菏泽市雷电灾害风险区划研究

为了明确不同县区雷电灾害风险的高低、防御和减轻雷电灾害,以闪电定位资料和经济社会资料为基础,采取归一化法、层次分析法、加权综合评价法,统筹考虑致灾因子的危险性、孕灾环境的敏感性、承灾体的易损性和防灾减灾能力4个评价指标,选择9个影响因子建立雷电灾害区划模型,绘制出菏泽市雷电灾害风险区划图。结果得出：曹县和东明是致灾因子危险性高值区,两地的孕灾环境敏感性同样较高,牡丹区和定陶是承灾体易损性高的区域,防灾减灾能力的高值区在牡丹区和东明。曹县和东明是雷电灾害的高风险区,次高风险区为单县和巨野,中等风险区为定陶,次低风险区为成武和郓城,牡丹区和鄄城由于防灾减灾能力强或致灾因子危险性较低划为低风险区。