Abstract:

To save the land occupation of line corridor, parts of DC grounding electrode lines may be set up with AC external power lines on the same tower or corridor. These two layouts both have the mutual influence problems of AC lines and DC grounding electrode lines. By using electromagnetic transient program (EMTP), the mutual influences of AC transmission lines and DC grounding electrode lines were studied on the condition that grounding electrode lines were set up with 35 kV AC transmission lines on same tower or with 330 kV AC transmission lines on same corridor. The results show that: when DC grounding electrode lines are set up with 35 kV AC transmission lines on same tower, the induced electromotive force caused by 35 kV AC lines on DC grounding electrode lines is little, its maximum value is less than 2 kV, which will not affect the DC system； the induced electromotive force caused by DC grounding electrode lines on 35 kV AC system is far less than the insulation level of 35 kV AC equipments, which will not cause harm to the safe operation of 35 kV AC system； when DC grounding electrode lines are set up with 330 kV AC transmission lines on same corridor, the maximum induced electromotive force caused by 330 kV AC line on DC grounding electrode lines is not more than 18 kV, which will not cause harm to the safe operation of DC grounding electrode lines. The research result has great significance for ensuring the safe and stable operation of AC lines and DC grounding electrode lines.

Key words: grounding electrode line, AC transmission line, on same tower, line corridor, electromagnetic transient program (EMTP)