带自熄弧功能的直流接地极线路用绝缘子并联间隙研究

Study on Insulator String Parallel Gap with Lightning Arc Extinction Characteristics Used in DC Transmission Grounding Electrode Line

直流接地极线路的作用是在换流站双极非平衡运行或单极大地回线运行时形成大地回流,由于设计缺陷接地极线路通过大电流时如果受到过电压冲击导致绝缘子间隙被击穿,有可能出现间隙无法熄弧,接地极线路设备被损坏的故障。以±800 kV宾金直流宜宾-共乐接地极线路为例,对接地极线路各种运行条件下的沿线电压分布和故障条件下的入地电流进行分析,提出了使用带自熄功能的接地极线路用绝缘子并联间隙解决现有接地极线路设计缺陷的思路,利用电磁暂态分析软件对该间隙在雷击条件下的电气特性和能量吸收进行了计算,论证了用带自熄弧功能的并联间隙取代现有接地极线路用并联间隙的可行性。

DC Transmission Grounding Electrode Line is used to form ground return current when HVDC substation bipolar run unbalanced or single polar ground return mode. Because of design defect in External insulation configuration,when string parallel gap is breakdown caused by overvohage impulse, electric arc may not blowout and power primary equipment may be damaged. Take the DC transmission grounding electrode line of ±800 kV Yibin-Jinhua UHVDC project as research object, voltage distribution along the grounding electrode line under various operation conditions as well as the current into the ground under fault conditions are analyzed.An insulator string parallel gap with lightning arc extinction characteristics is proposed to overcome the design defect of current DC transmission grounding electrode line. To demonstrate the feasibility of insulator string parallel gap with lightning arc extinction characteristics, electromagnetic transient analysis software ATP-EMTP was used to obtain electrical characteristics and absorbed energy when lightning stroke the DC transmission grounding electrode fine.