Research And Field Application On Lightning Protection Measures For Distribution Network

10kV distribution lines occupy an important position in the power system,playing a vital role in ensuring the safety of national production and people’s daily life.Since the distribution network has its own characteristics,lightning can easily lead to line tripping accidents and the damage of the power grid equipment.The existing principle of lightning protection measures can be divided into two categories,"grooming" and a "blockage".The former uses special protection tools such as arc-protection hardwares,clamp insulators and others to protect the line against disconnection faults,The latter improve tha anti-thunder level of the lines by increasing the insulation level or preventing power-flow current with arresters.However,in the anti-thunder measures such as arresters,arc-protection hardware,discharge clamp insulators,lightning arresters can’t play a protective role if the discharge gap distance is not accurate or the location is changed in the process,which is because workers don’t reach the designated position.The arc-protection hardwares need to puncture wire and clamp insulators require to strip off the wires,destroying the overall structure of the wire and threatening the safe operation of the power grid.Therefore,it is of great significant to propose economic and reasonable lightning protection measures through the study of the distribution network of existing anti-thunder technology and measures.Based on the problem of the lightning strike tripping,the paper points out that the main cause of the problem lies in lightning overvoltage.Having explored the theory and calculation methods of lightning overvoltage on the power distribution lines,the paper indicates electrostatic induction component is the main component of the lightning overvoltage of the distribution line.Through the means of theoretical study and experiments,the paper proposes a new anti-thunder disconnection device,that is,an externally and internally installed column voltage limiter,shuld be created by combining the post insulators and the over-voltage protector.It has features of simple installation,high reliability,being free of maintenance and causing no damage to wires and so on,which will contribute to the development of anti-thunder measures of the distribution lines and the safe and reliable operation of the grid.Through the analysis of the lightning strike data on the distribution lines of Zichuan,Zibo City in recent years,taking network operation with new devices of Gudong line for example,the paper analyzes and concludes that the new devices have achieved the expected effect,providing technical and product support to solve the anti-thunder problem of aerial insulation lines.