多频率组合测量冲击接地电阻方法  

Measuring Impulse Grounding Resistance by Multi-Frequency Combination Method

作　　者：马御棠 高竹青[2] 曹晓斌[3] 周仿荣 杜俊乐 田明明[3] 

机构地区：[1]云南电网有限责任公司电力科学研究院,云南昆明650217 [2]国网山东省电力公司潍坊供电公司,山东潍坊261021 [3]西南交通大学电气工程学院,四川成都610031

出　　处：《西南交通大学学报》2017年第4期782-788,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金杰出青年基金资助项目(51325704)

摘　　要：为准确测量输电线路杆塔接地装置的冲击接地电阻,基于傅里叶变换原理,提出一种多频率组合测量冲击接地电阻方法.首先,将标准雷电冲击波进行周期延拓,利用傅里叶变换将其展开为三角函数级数,给出了测量所需的基波与各次谐波频率;建立了测量源与傅里叶级数项之间的幅频和相频对应关系,通过比例缩放与移相,将不同频率测量结果转化为对应傅里叶级数项的响应函数;利用傅里叶反变换合成冲击响应波形,计算得到冲击接地电阻.然后,分析了测量所用频率个数对测得的冲击接地电阻的影响,发现频率点数量从50个增大到120个时,测量与仿真的偏差21%下降到9%以下.最后,利用实验验证了该方法与直接采用冲击电源测量结果的一致性,实验结果表明,在相同的测量接线方式下,所提方法与冲击装置测得的结果差小于10%.To measure the impulse grounding resistance of transmission line towers accurately, a multi-frequency combination measurement method based on Fourier transformation is proposed. Firstly, a standard lightning impulse waveform was extended as a periodic function. This function was then expanded as a trigonometric series via Fourier transformation. Frequencies of the fundamental wave and harmonics were thus obtained, and amplitude and phase of relationships between the measured source and corresponding Fourier series terms were described. Through scaling and phase shifting, the measuring results were converted to a response function of Fourier Series terms using different frequency components. The impulse response waveform was obtained via the inverse Fourier transformation, yielding the impulse grounding resistance. The effect of the number of Fourier Series terms on the impulse grounding resistance was analysed. It is found that if the number increases from 50 to 120, the deviation between measurement and simulationresult drops from 21% to 9% . Finally, physical experiments have verified that this adopted method is consistent with the direct impact power measurement results. Experimental results show that under the same measuring connection mode, the difference between the measuring result presented here and that of the percussion device is less than 10% .

关 键 词：傅里叶变换 雷电流 冲击接地阻抗 接地网 

分 类 号：U224.24[交通运输工程—道路与铁道工程]