| Distribution line is used to transmit the electric energy to the consumers.The breakdown of the distribution line will affect the reliability and stability of the electric power system.Zhuli is located in the north central of Zhejiang province and has an enormous population. By developing a lot of industry and commerce.it became the second one of the richest counties in2013.In order to meet the demand of the electrical power from the living and production,the10kV distribution lines are quite huge in Zhuji.According to the data provided by the meteorological bureau of Zhejiang province,the distribution lines of Zhuji power supply company are located in the areas where the cloud to ground flash density is very high and annual thunderstorm days are more than40(the highest one approached50).Due to the low isolation of the distribution lines, the complexity of the operation condition and the imperfection of the lightning protection, the reliability of the distribution lines is affected by the damage caused by the lightning.Here we analyzed the lightning protection of the distribution lines in Zhuji and presented methods to improve the supply reliability.1.We analyzed the distribution and law of the damage of the lightning to the Zhuji’s distribution lines based on the related data in the past5years.At the same time.we measured the tower grounding resistance, tower structure parameter.circuit parameter and the soil resistivity.Finally we gave an explanation why the lightning stroke trip rate is high in the distribution lines of this area.2. Most of the damages by the lightning in the10kV distribution lines are due to the lightning induced voltage.We analyzed the lightning induced voltage in the distribution lines in Zhuji theoretically and presented an optimization in the installation of the arresters.3. Using the technology outsourcing mode,we built up a model of the10kV distribution lines based on the electromagnetic simulation software (EMTP-ATP).We simulated the lightning withstand level when the tower and the conductor are struck by lightning, respectively,in order to give a better suggestion of the installation of the arresters in Zhuji.4.With further simulation,we analyzed the characteristics of the over voltage protection device.Aiming at the outer gap distance error in the current over voltage protection device--the horn electrode,we replaced it with the ring electrode.We optimized the installation procedure of the over voltage protection device and improved the speed of the installation, well as reduced the distance error of the horn electrode due to the installation. |
PDF Full Text Request