| 10kV overhead distributions is an important part of distribution network which is generally used to deliver power from converting station to terminal substation. However, distribution network will break down in thunderstorms weather when overhead conductor breaks and circuit trips off. This is because lines for 10 kV overhead distributions are low in insulation level and complex in line corridor. Situations for mountain areas are more serious. Lightening trip damages distribution equipments, causes power cutting off, and lower reliability of power supply, which largely influence people’s productions and electricity.Zhaoqing is a place occupied with mountains. So most of its overhead distribution lines are constructed in the mountain. This dissertation will first introduce theories of distribution line thundercloud and basic parameters of lightning, through the example of Zhaoqing. Through analysis of 10 kV distribution line’s tripping in Zhaoqing, this dissertation finds that low levels of insulation is the main reason for tripping of distribution line thundercloud and high rate of breakage.Second, through PSCAD, this dissertation simulates the lightning of 10 kV distribution line. The lightning current model, tower model, insulator flashover criterion model, and 10 kV distribution line simulation model help to simulate how induction lightning over voltage and lightning over voltage influence 10 kV distribution line. Further, it compares six commonly used lightning protection measures of their effects under the thought of ‘Four defenses’. The findings point out methods to improve level of anti-lightning and provide foundations for development of anti-lightning strategies.Finally, based on previous research, this dissertation finds suitable methods to improve lightning for Zhaoqing’s 10 kV distribution center. Through the comparison of rates of tripping and accidents Before and After, it proves the effectiveness of anti-lightning strategies. |
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