接地极长度对其接地阻抗频谱特性的影响研究

Study on the influence of grounding electrode length on its ground impedance spectrum characteristics

杆塔接地性能决定输电线路的耐雷水平,腐蚀导致接地极断裂,长度减少。为了研究频率响应法在接地极长度诊断中的可行性,研究接地极长度对其接地阻抗频谱特性的影响。搭建三种常见结构接地极的仿真模型,运用CDEGS软件仿真得到不同电源频率下接地极的接地阻抗;通过分析阻抗模和阻抗角的频谱响应曲线,找出不同结构下长度对接地阻抗的共同影响规律;通过实验对该规律进行验证。频率较低时,接地极长度对阻抗模值有较大的影响;频率升高后,不同长度接地极的阻抗模值逐渐相同,而阻抗角有较大的差异;随着频率进一步升高,不同长度接地极接地阻抗的模值与阻抗角都相同。提出如果以50 Hz的阻抗模值为基准,可通过模值倍增时所需要的频率对接地极长度进行检测。

The grounding resistance of the tower determines the lightning withstand level of the transmission line,the corrosion will lead to the breakage of the grounding electrode and the decrease in the length.In order to study the feasibility of frequency response method in the diagnosis of grounding electrode length,the influence of the length of grounding electrode on the spectrum characteristics of grounding impedance is studied.Tthree simulation models of common structural grounding electrodes are built.The grounding impedance of the grounding electrode is simulated under different power frequency by using CDEGS software.By analyzing the frequency response curves of impedance mode and impedance angle,the common influence rule of length to ground impedance under different structures is found.The experiment is used to verify the law.The length of the grounding electrode has a great influence on the impedance modulus when the frequency is low;when the frequency increases,the impedance modulus of the grounding electrodes with different lengths is gradually the same,and the impedance angle is quite different;However,as the frequency increases further,the grounding impedance of the grounding electrode with different lengths is the same as that of the impedance angle.If the impedance modulus of 50 Hz is used as the benchmark,the frequency needed to dock the electrode length can be detected by multiplying the module value.