一起矿区电网雷击打坏主变事故分析及改造措施

Analysis and Modification Measures of a Lightning Damage Accident of Main Transformer in Mining Area Power Grid

针对屯兰110 k V变电站发生的雷击打坏主变事故,并结合现场调查和实验室试验情况,对事故的原因进行了计算分析。认为母线避雷器的接地引下线太长、变电站的冲击接地电阻过大、雷电过电压未经过进线段保护进行有效限制,侵入的雷电波幅值过高是这起雷害事故的主要原因。提出了以下针对性的改造措施:对变电站的接地装置进行优化改造、规范站内避雷器接地引下线的长度及布设位置、在进线段杆塔上装设无间隙的氧化锌避雷器、对装设有线路避雷器杆塔的接地装置和接地电阻进行检测。通过以上改造,消除了变电站防雷保护的隐患,大大提高了矿区电网的供电可靠性。

According to the lightning damage accident of main transformer in tun-lan 110 kV substation, and in combination with the information of field investigation and laboratory test, the reason of the accident is discussed in the paper. Considering that the ground down lead of surge arrester is too long, the impulse grounding resistance of the substation is too high, the lightning waves intrusion substation without the effective restrictions of inlet lines protection is the main reason of the accident. The following targeted modification measures are put forward： Optimizing the substation grounding device, normalizing the length of grounding down lead of surge arrester, installing the Zinc Oxide lightning arrester on inlet lines towers, and testing the tower grounding device of the towers which installing the Zinc Oxide lightning arrester. Through the above measures, the hidden trouble of lightning protection in transformer substation has been eliminated, and the power supply reliability is greatly improved.