防振锤技术参数对其功率特性的影响分析

为了设计新型防振锤,需要确定防振锤各技术参数对其功率特性的影响程度。本文针对FD型防振锤,计算了防振锤各技术参数对其谐振频率和功率特性的影响程度,并对造成不同影响程度的原因进行了分析,指出在防振锤的设计过程中,应特别注意锤头之间的配合,明确技术参数对锤头功率特性的影响程度,通过理论和实验确定各技术参数的最佳值。     

FD型防振锤的动力特性研究

基于防振锤设计参数推导了防振锤锤头的质心位置和转动惯量,建立了防振锤的数学分析模型,给出将防振锤简化为数学模型的方法.以FD型防振锤为例对其动力特性展开研究,为防振锤的结构设计改进提供参考.研究表明:通过改变设计参数α可以控制防振锤二阶固有频率,通过调整设计参数α和β可以调节防振锤一阶固有频率;设计参数α和β对防振锤功...     

蒙东地区架空输电线路防振锤断裂破坏原因分析

防振锤是为防止风致振动断股而悬挂于导线上的重要金具种类。蒙东地区架空输电线路防振锤在运行过程中出现了锤头本体断裂的异常现象。针对这一问题开展了防振锤的化学成分分析、金相组织分析以及断口微观形貌分析等。结果表明,该防振锤锤头材质为灰铸铁,碳当量较高,超出ISO185标准规定值,金相组织为珠光体、粗大片状石墨和少量的铁素体,且锤头内部可能存在较大残余应力,锤头断裂机制为脆性解理断裂。建议今后防振锤设计制造工作中,对材料成分进行适当控制,同时应进行去应力热处理或者改用冲击韧性良好的材料代替铸铁材料,并优化锤头结构和尺寸,防止断裂事故的发生。     

330kV线路用FR型防振锤结构优化

330kV输电线路所采用的FR-3型防振锤结构复杂,其锤头形似音又,两端面的曲率半径较小,导致其场强较高,在实际运行中可能会发生电晕放电,从而对周围的电磁环境造成污染。采用有限元方法建立FR．3型防振锤的三维模型进行电场仿真计算,得出了防振锤的电场分布规律,据此优化了其锤头的音叉结构,将锤头端部的最高场强由3000kV...     

高海拔地区FDN型防振锤防晕性能优化

采用有限元法建立FDN型防振锤的三维模型进行仿真计算,得到了其锤头的电场分布规律,优化了小锤头结构,将锤头端部的最高场强由2 987 V/mm降至2 390 V/mm。根据优化结果制造试品后,对其进行不同气压下的电晕试验和功率特性试验,结果表明优化后的防振锤在4 300 m海拔下可有效地防止电晕放电,且谐振频率和功率消耗满足要求,峰谷值之比优于旧结构,具备良好的防振性能。     

防振锤结构与力学性能研究进展*

防振锤是架空线路中一种典型的防振装置,常用于抑制输电线的风致振动,减轻输电线的微动损伤.从防振锤的结构和力学性能两个方面的研究进行论述.首先根据防振锤的发展历程,介绍了国内外典型的防振锤,阐述了它们结构上的区别及各自的优缺点,并以Stockbridge型防振锤为例,解释了防振锤的防振机理;此外,简述了防振锤线夹和锤头结构优化的案例.然后对防振锤的力学模型和力学性能进行了说明,并按照理论推导、仿真分析、振动试验三种研究方法,总结了国内外有关防振锤力学性能方面的研究.最后根据国内外关于防振锤结构和力学性能的研究成果,对防振锤的结构改进及其他特性研究进行了展望.     

基于现场风特征的架空地线防振锤故障分析

为研究新疆地区某线路地线防振锤连续2年锤头掉落的原因,测量了当地风速和风向数据,结合该线路的走向、所处地形和地线结构参数对风数据进行了分析.结果表明:该线路地线所处环境符合发生微风振动的条件,且由当地风引起的地线振动频率与所用防振锤低阶共振频率相近;判断地线的微风振动导致防振锤长期处于低阶共振状态,是地线防振锤锤头掉落...     

高海拔地区330 kV 线路用 FD 型防振锤防晕性能优化

西北地区的330 kV 线路地处高海拔地区,线路上采用的 FD-5型防振锤普遍出现了显著的电晕放电现象,既造成功率损耗,又产生可听噪声和无线电干扰.为此,对防振锤的结构进行优化,以使其在高海拔地区正常运行时无电晕发生,同时保证防振性能满足要求.根据有限元法建立了FD-5型防振锤的三维模型,通过仿真计算,得出了锤头的电场强度分布规律,并对其结构进行优化,使锤头上的最高场强降低了17%.根据优化结果制造试品后,对试品进行低气压下的电晕试验和功率特性试验,结果表明:优化后的防振锤运行在海拔3500 m 时可有效防止电晕放电,谐振频率和功率消耗减小幅度低于6%,但是其峰谷比小于5,防振性能依然良好     

防振锤的新结构

本文简单介绍了国内外防振锤的锤头结构形式及其性能特点,详细论述了新型铆接防振锤的结构形式、性能特点及其振动试验和握力试验,同时对套管的抗导线滑动力经验公式进行了推导、计算。     

防振锤功率特性数值仿真与动力学优化

针对防振锤在不同工况下无法发挥最佳防振性能的问题,构建防振锤子系统模型,简化功率特性数据采集方程,设计实验装置对防振锤进行功率特性数值仿真计算,得到防振锤的功率特性曲线,并采用Kriging模型对防振锤的绞线抗弯刚度、绞线股间摩擦系数、材料内阻尼进行动力学优化。模拟实验结果表明：仿真结果与测定结果较为吻合,防振锤的功率特性仿真数值具有可靠性;在不同频率工况下,优化后输电导线的振幅、比振幅较小,说明防振锤功率消耗较大,具有更好的防振性能。     

无GGH-FGD运行特性分析和设计应注意的问题

针对600MW机组有/无GGH-FGD设计性能和运行特性进行了分析,对无GGH-FGD运行中出现挡板泄漏和烟道腐蚀的问题提醒设计和运行中应注意事项。建议脱硫工程师应注意从实际运行特点中积累烟道及挡板和湿烟囱的腐蚀情况,及时反馈到设计中和设备的采购技术要求中。使有中国特色的无GGH-FGD装置逐渐完善。     

谟武水电站灯泡机组现地控制单元设计及有关问题探讨

灯泡贯流式机组具有技术参数高，运行性能优越，可靠性高，并能节省土建投资等诸多优点，近年来已逐渐在低水头电站广泛使用。目前，国产灯泡贯流机组现地控制单元采用计算机的极少、文中结合福建省顺昌谟武电站灯炮贯流机组现地控制单元的设计，对有关问题进行探讨，可供国内同类型电站设计时参考。     

小型轿车磁流变减振器设计与仿真

基于磁流变的基本理论和磁流变液的工作特性,分析磁流变减振器的工作原理与力学模型,确定活塞阻尼力与磁流变液的粘度阻力、剪切力和摩擦阻力之间的数学关系;设计车辆磁流变减振器的结构,计算、选择其结构参数,并建立仿真模型。仿真结果表明,设计是可行与合理的,符合车辆减振器的设计要求,其控制简单且响应迅速。     

Experimental study of squirrel-caged damper structure for superconducting generator

In this paper a double-layer damper is developed which will consist of a squirrelcaged warm damper and a cylindrical cold damper as a part of a 70-MW superconducting generator development project. To evaluate the characteristics of unbalance current capability, magnetic shielding and damping for rotor swing, a one-half scale rotor model is constructed and an experimental study is made. From analysis of the experimental results, design guidelines have been developed and the FEM magnetic field analysis technique is refined. The main results are summarized as follows:

• 1 The squirrel-caged warm damper has sufficient capability against negative sequence current;
• 2 Damping characteristics can be designed to be effective near the rotor swing frequency;
• 3 Flux shielding at low frequencies corresponding to quick response excitation is sufficiently small so as not to prevent field flux change; and
• 4 Magnetic field can be analyzed by the refined FEM field analysis technique which now takes into account the effects of the rotor end region by estimating the end resistance based on the eddy current flow path.

     

AN APPROACH TO IMPROVING DYNAMIC STABILITY OF SUPERCONDUCTING GENERATOR USING Q-AXIS DAMPER WINDING FEEDBACK CONTROL

Abstract

Q-axis damper Minding feedback control offers a means for improving dynamic performance of superconducting generator.This paper is an investigation of dynamic characteristics of a machine with such a control system. A model based on Park's equations in the form of Fourier Transform of the machine is proposed and used to simulate the dynamic behaviour of the generator after the occurance of a small disturbance of torque or voltage of the power source.From the computer simulation results, it was proved that the system can offer sufficient damping effects and an optimum design can be reached by choosing parameters of the control system carefully. Also,it is a more economic method compared with those proposed by others [4,5,6].     

多逆变器并网系统谐振混合阻尼参数设计

多逆变器并网系统谐振是高比例新能源新型电网必须解决的问题。文中分析了改进型有源阻尼、阻抗重塑和有源阻尼器的优缺点后,认为混合阻尼策略更符合工程经济需求。首先,介绍了单台LCL型逆变器混合阻尼参数设计过程;然后,在分析多逆变器系统谐振机理的基础上,根据混合阻尼的阻尼系数特点,提出先确定有源阻尼参数再确定无源阻尼参数,并采用总谐波率和谐波系数两个指标评价并网电能质量的参数设计方法;最后,在Matlab/Simulink仿真平台上进行验证。结果表明,所提方法设计的混合阻尼参数对系统谐振具有良好的抑制效果,并且能较好地适应系统阻抗的变化。     

关于防振锤力学性能的探讨

通过防振锤受力分析,建立防振锤数学模型,并以此数学方程为基础,讨论了防振锤的力学性能,包括功率特性、自振频率、力频响应及相位特性等,同时还探讨了防振锤的疲劳试验方法。以利于我国防振锤参数的设计和性能的提高。     

Experimental study on harmonics reduction effects of damper windings in a synchronous generator

With the recent development of power electronics technology, thyristor-controlled equipment has largely been introduced to the electric power system. These devices generate harmonics that cause voltage distortion and undesirable effects on the power system components. On the other hand, the damper windings of synchronous generators basically are designed to reduce harmonics as well as to damp out system oscillations. However, up to now, the effects of damper windings on harmonics have not been clarified fully in a quantitative way. In this paper, the results of experimental study on the harmonics reduction effect of damper windings have been presented. A specially designed 6-kVA generator was connected to an infinite-bus system to investigate the characteristics of damper windings. A new method to measure induced voltages between damper bars, damper bar currents and air-gap flux densities in the tested generator was established. By comparing these measurements with and without the presence of damper windings, the effect of damper windings was quantified. Thus the reduction effects of the damper windings on slot ripples and harmonics caused by armature current mmf were investigated and were made clearer than before by the proposed method.     

Acceptance curve — A practical means for EHV transmission line damper performance evaluation

The evaluation of the suitability of a damper for an EHV transmission line can be divided into two parts. The first is the evaluation of the damper performance independent of the line, either by (a) the direct absolute power method, or (b) the relative wave power method. The second and more important part is the verification of the suitability of the damper for a given line. Two common methods may be used for this second part: (a) Preparation of an acceptance curve by initial computation with no reference to the damper, but only to a conductor fatigue damage criterion in conjunction with the line and wind parameters. The damper performance curve, determined independently, can be compared directly with this acceptance curve. (b) Direct computation which uses the damper characteristics together with the line and wind parameters at the final stage to estimate the amplitude of vibration, or dynamic strain, which is compared with the specified value depicting a fatigue damage criterion. This paper reviews these methods and points out, from the point of view of both the manufacturer and the user, the simplicity of the method using the acceptance curve. The procedure for establishing an acceptance curve is illustrated. Examples of acceptance curves, their use and characteristics are included.