CAJ | 학술논문

接地系统是维护电力系统安全可靠运行的重要基础设备。从频II介电谱理论出发，开展了土壤频变特性的研究。为了降低电极极化效应影响，配制了含水量较高、电阻率较低的土壤样品。然后进行了不同含水量、不同含石量的土壤介电谱的测量，对测得的数据进行函数拟合并代入有限元冲击特性模型中进行计算，分析了土壤电气参数的频变特性对冲击接地性能的影响。结果表明：冲击电流作用下，接地极周围土壤的介电常数随频率在低频段近似符合幂函数规律，在高频段近似符合指数函数规律；在同一频率点，土壤的介电常数随土石比例和含水量的降低而减小；考虑土壤介电常数频变特性后，冲击电流作用下接地极暂态电阻值与介电常数恒定时相比有显著的差异。
접지계통시유호전력계통안전가고운행적중요기출설비。종빈II개전보이론출발，개전료토양빈변특성적연구。위료강저전겁겁화효응영향，배제료함수량교고、전조솔교저적토양양품。연후진행료불동함수량、불동함석량적토양개전보적측량，대측득적수거진행함수의합병대입유한원충격특성모형중진행계산，분석료토양전기삼수적빈변특성대충격접지성능적영향。결과표명：충격전류작용하，접지겁주위토양적개전상수수빈솔재저빈단근사부합멱함수규률，재고빈단근사부합지수함수규률；재동일빈솔점，토양적개전상수수토석비례화함수량적강저이감소；고필토양개전상수빈변특성후，충격전류작용하접지겁잠태전조치여개전상수항정시상비유현저적차이。
Grounding system is an important foundation to maintain safe and reliable operation of power system equipment. In this paper, the frequency characteristics of soil were studied by the frequency domain dielectric spectroscopy theory. To reduce the effects of electrode polarization, the soil samples with high water content and low resistivity were mixed. Then the soil dielectric spectrum with different water contents and amounts of rock was measured, and the data were fitted to mathematical functions. Then the function was merged into the finite element model to calculate the impact characteristics and the influence of the frequency variability of soil electrical parameters on the impact characteristics of grounding electrode was analyzed. The results show that the relationship between the dielectric constant and frequency is the power function within the low frequency and the exponential function in high frequency. At the same frequency, the dielectric constant of soil decreases with decreasing soil-stone ratio and water content. Considering the frequency characteristics of soil permittivity, the transient grounding resistance value under impulse current is very different from that calculated with constant permittivity.