换流站交流滤波电容器外壳振动研究

为了合理估算电容器噪声辐射水平,需要研究电容器外壳振动形式。通过对带电电容器外壳面采用密集网格测点的振动测试实验,得到以下电容器外壳振动的特性:电容器外壳各面的振动形式为缩涨振动;侧面振动相位一致,侧面振动相位与底面振动相位相差半个周期,也即侧面缩时底面涨;底面振动幅值远大于侧面振动幅值,侧面振动幅值基本一致。电容器噪声估算可以采用外壳面的平均振动幅值,电容器外壳面的噪声辐射比为1。     

基于电致噪声频响函数的多谐波工况下换流变压器噪声等效评估方法

现行变压器噪声测试标准仅规定工频试验条件,使得换流变压器实际运行的噪声远超过测试水平。因此在规划换流站前,需要准确评估换流变压器的出厂噪声。该文以等效实际多谐波运行工况为目标,提出单频叠加和降容量两种换流变压器噪声等效评估方法。单频叠加试验是利用单一频率激励加载噪声试验结果,通过叠加定理来评估复合频率激励加载下换流变压器噪声水平;降容量试验是在多频谐波电源容量不能满足直接加载情况下的一种替代加载方案,降容量试验结果加上40 lgm(m为降容比例)得到全容量下的噪声水平,并通过分析比较实测和评估的噪声频率特性及声场分布验证所提方法的有效性和准确性。结果表明,单频叠加试验得到的噪声误差均在1.8 dB以内,降容量加载试验得到的噪声误差均在1.6 dB以内,相比以往工频加载方式大幅度提升了换流变压器噪声评估的准确性。所提等效评估测试方法为换流变压器制造厂家掌握产品运行噪声性能提供了有效方法,同时能够为换流站噪声设计与治理提供有力支撑。     

基于电场探头及电流传感器的MOA运行状态带电检测方法研究

作为一种电力保护设备,金属氧化物避雷(MOA)运行状态的准确识别是确保电网安全高效运行的前提之一。针对传统MOA运行状态检测方法中存在的检测准确性低,无法进行带电检测等问题,笔者提出了一种基于各次谐波原理的MOA非接触式带电检测方法。该方法采用一种改进的差分式电场探头和钳式电流传感器(CT)实现对于MOA电压与电流的信号采集,在此基础上对两路信号进行快速傅里叶变换(FFT),得到阻性电流等参数以实现对于MOA的检测。本研究开发了样机,详细介绍了样机的结构,推导了其传递函数,并分别对正常运行状态的MOA、老化和受潮的MOA进行了测试试验。结果表明,该样机能够准确采集到MOA阻性全电流、阻性基波电流及阻性3次谐波电流等参数,正常运行状态时幅值大小分别为23μA、17μA、5μA,受潮、老化相关状态下,阻性基波电流分别达到35.3μA和30.2μA,阻性3次谐波电流分别达到6.2μA和15.1μA,针对3种状态样机检测结果与在线监测系统基本保持一致,电流相对误差可达0.5%,且与已有文献相吻合,说明所开发样机符合MOA带电检测要求,具有良好的工业应用价值。     

电力变压器空载状况下的振动特性研究

利用振动测试系统测试电力变压器空载状况下各相振动情况 ,以此研究空载时变压器器身的振动特性。该法与电力系统没有直接的电气连接 ,故效果良好 ,研究表明变压器器身振动基频为 10 0 Hz,10 0 0 Hz后谐波衰减至 0     

Application of Excitation Function to the Prediction of RI Level Caused by Corona Discharge

Radio interference (RI), as an aftereffect of corona discharge, is an important research topic in the field of electromagnetic compatibility, where excitation function is applied broadly to the prediction of RI level. This paper presents the theory of excitation function method used in the RI level prediction. Then, some practical problems related to this method are discussed. The propagation procedure of corona current is solved by the phase-modal transformation, and the impedance matrix of multi transmission lines is calculated by a double logarithmic approximate model of Carson’s Ground-Return impedance. At the same time, in order to calculate the RI level when total line corona is assumed, an analytical formula is deduced for integral operation. Based on the above solutions, an algorithm is presented and applied to the prediction of RI level of a practical overhead transmission line. Comparison of prediction and measurement results indicates that the algorithm proposed in this paper is effective and feasible.     

浅析1000kV特高压输电线路防雷

特高压输电线路防雷,是保证特高压输电线路安全运行的重要环节之一。介绍并分析了利用规程法和电气几何模型法对1 000 kV特高压输电线路绕击、反击以及雷电直击中线进行雷击计算的结果,并据此提出了减小1 000 kV特高压输电线路雷击跳闸率的具体措施。     

特高压串联电容器补偿装置噪声的Sysnoise仿真

文章提出了使用Sysnoise对电容器装置噪声仿真计算的思路和实施方法,对特高压串联补偿电容器装置进行了仿真计算和声场分析。首先论述了使用Sysnoise计算电容器装置噪声的理论依据,给出了仿真计算的步骤。然后介绍了测量外壳振动速度的实验系统,用于确定振动速度的边界条件。将该方法应用于特高压串联补偿电容器装置计算中,获得了装置噪声声场分布的结果。分析得出特高压串补电容器声场有随距离衰减和干涉的特征,声场噪声水平较低。     

多种试验条件下SF6放电及分解特性研究（英文）

Detection of gas decomposition products is widely used for condition diagnosis of SF6-insulated equipment because of its an- ti-electromagnetic-interference ability and high sensitivity. Previous investigations show that the volume of gas chamber influences the types and concentrations of SF6 decomposition products. Therefore using a newly developed dual gas chromatography (GC) detection sys- tem we investigated the discharge and decomposition of SF6 in a discharge chamber with its volume close to that of the real chambers in GIS. Tests in the chamber were performed with different applied voltage, different electrode arrangements, and different defect types. For discharge between needle-to-plane electrodes, the typical gas decomposition products are SO2F2, SO2 and S2OF10. A near linear growth with the increase of voltage duration is found in the concentration of SO2F2, whereas the growth rates of SO2 and S2OF10 concentration decrease with time. Concentrations of SO2F2, SO2 and S2OF10 at the same voltage duration decrease with the decrease of the voltage amplitude and the increase of the needle-to-plane distance. Change of the gas chamber volume affects the generation rates of SO2F2 and SO2, however not S2OF10. For insulator surface defects, the typical gas decomposition products are CF4, CS2 and SO2. Among which, the concentrations of CF4 and SO2 increase with the voltage duration almost linearly. Moreover, a new parameter that represents the degree of SF6 degradation, the SF6 deterioration ratio, is proposed. In the needle-to-plane case, SF6 deterioration ratio is positively correlated to the fitting value of an averaged discharge capacity. However, the maximum value of SF6 deterioration ratio varies with the defect type.     

电容器单元间噪声相互影响及装置声场优化措施

随着高压直流输电系统输送功率日益增大,换流站噪声问题变得更加严峻。交流滤波场中电容器装置是主要的噪声源之一,其降噪需求日益提升。本文通过对电容器外壳表面进行振动形态的实际测量,建立多台滤波电容器装置仿真模型即滤波电容器装置简化仿真模型,分析空间距离、安装方式对电容器单元间噪声的相互影响。仿真得出电容器单元间的底面间距和...     

电压互感器饱和引起铁磁谐振过电压的定性分析与仿真验证

分析了系统中各参数对于铁磁谐振的影响,并利用数值仿真说明了定性分析的正确性.