植被含水率对导线触树单相接地故障特性的影响分析

Effect analysis of vegetation moisture content on a tree-contact single-phase-to-ground fault

输配电线路走廊的导线触树单相接地故障可能引燃植被、诱发火灾,威胁线路的正常运行。植被含水率是影响导线触树单相接地故障的重要因素,但含水率对故障发展过程、故障特性的影响尚不明确。以典型植被桉树为对象,开展了导线触树单相接地故障试验研究。基于试验现象及泄漏电流波形,从炭化通道发展及含水率变化的角度分析了植被高阻接地故障发展过程,研究了含水率对故障过程中泄漏电流、炭化通道、等效电阻等特性的影响规律。随后,揭示了泄漏电流第一峰值与含水率关系,建立了基于植被长度、直径、含水率的泄漏电流第一峰值预测模型,通过试验验证了预测模型的准确性。该研究成果对于导线触树单相接地故障的检测、诊断及预测具有重要意义。

A tree-contact single-phase-to-ground fault of a transmission and distribution line corridor may ignite vegetation,cause fire,and threaten the normal operation of the line.Vegetation moisture content is an important factor affecting the single-phase grounding fault of a conductor contact tree,but its influence on the fault development process and fault characteristics is still unclear.In this paper,a single-phase ground fault test is carried out on a typical vegetationeucalyptus.Based on the test phenomenon and leakage current waveform,the development process of vegetation high resistance grounding fault is analyzed from the perspective of carbonization channel development and moisture content change.The influence law of vegetation moisture content on leakage current,carbonization path,equivalent resistance and other characteristics during the fault process is studied.Then,the relationship between the first peak value of leakage current and water content is revealed,and a prediction model of the first peak value of leakage current based on vegetation length,diameter and water content is established.The accuracy of the prediction model is verified by experiment.The results of this study are of significance to the detection,diagnosis and prediction of a single-phase ground fault of a wire contact tree.