辐射状接地体冲击接地阻抗特性的实验

为了研究辐射状接地体的冲击接地特性,用实验的方法得到了2种辐射状接地体的冲击接地阻抗TGR(transient grounding resistance)。实验所用接地体,其一,由8根长2m的钢筋组成米字形接地体;其二,由4根长4m的钢筋组成十字形接地体,材料均为10钢筋,埋深0.6m。实验时高压脉冲发射器经接地体入地点放电,由脉冲电流传感器和脉冲电压传感器测得的信号经光纤传输系统传送至多路数字示波器,根据同步记录、存储的波形,计算得出了冲击接地阻抗波形。实验结果表明,在实验冲击电流下,米字形接地体的冲击接地阻抗呈现明显的容性特征,而十字形接地体的冲击接地阻抗容性特征不明显;冲击接地阻抗时域波形的稳定值与工频接地电阻的理论值非常接近。

Experimental investigation of transient grounding resistance characteristics on spokewise grounding electrode

To invest igate the t ransient g rounding characteristics of the spo kew ise g rounding elect rode, the t ransient g rounding resistances of the tw o kinds of spokew ise grounding elect ro de w ere obtained fr om the field measurements. Each kind of g rounding elect rode w as made of reinfo rcing steel bars w ith the diameters o f 10 mm and the total leng th of 16 m w as buried horizontally at the depth o f 0. 6m from the g round surface. T he star -shape grounding elect rode w as composed o f 8 reinfor cing steel bars. The cross-shape o ne w as compo sed of 4 reinforcing steel bars. A pulse dischar ge f rom a high-voltag e pulse g enerato r w as applied at the center of the g rounding elect ro de to o bser ve the t ransient vo ltag e and the curr ent on it . T he measured wav eshapes w ere synchronously reco rded, and the t ransient gr ounding resistance w as calculated and analy zed. The exper iment result s suggest the obvious capacitiv e character ist ics on the star-shape gr ounding elect rode, and the accordance betw een the stable v alue of T GR and the theor et ic v alue of the pow er fr equency gro unding resistance