Research On Key Parameters In Calculation Of Transmission Line Lightning Stroke Trip-out Rate Base On Lightning Detection Data

At present, lightning stroke is still the first cause of transmission line trip outs. Reducing the transmission line lightning striking trip-out rate will be of great significance on power gird operation. Precisely predicting the transmission line trip-out rate will not only help to analyze if the program of transmission line corridor is reasonable, but also be useful to guiding the lightning-proof reconstruction.Generally speaking, the calculation formula of the transmission line lightning striking trip-out rate frequently used in engineering is relevant to some parameters just like the quantity of lightning stroking on transmission line, the rate of lightning current amplitude over the striking lightning withstand level, etc. In recent years, scholars mainly focus on raising accuracy of the back striking lightning withstand level and using EGM(Electric Geometry Model) to calculate shielding failure rate of transmission lines. However, other empirical parameters are still used in calculation, and it produces errors without doubt.In the past few years, more and more new lightning detection system have been used in power gird, and LLS(Lightning Location System) is the typical representative. These equipment have detected large number data of lightning since they put into use. This paper uses the detected data to research four key parameters in the calculation of transmission line lightning striking trip-out rate, which cover the distribution of cloud to ground flashs, probability distribution of lightning current amplitude, lightning attractive width and lightning striking rate on poles. The first two parameters are relevant to both back striking and shielding failure when the last two parameters are just related with back striking.Firstly, this paper researchs the temporal distribution of cloud to ground flashs in Hainan basing on the data of the lightning location system in Hainan power grid. In addition, the space distribution of cloud to ground flashs is also researched, and the areas where the lightning activities are more active are found out.Secondly, the probability distribution of lightning current amplitude in Hainan is studied. And probability distribution is compaerd to the regulation method. What is more, this paper fits the lightning current amplitude accumulative probability formula which can be uesd in calculation of transmission line lightning striking trip-out rate.Thirdly, this paper introduces the calculation method of lightning attractive width by using the data of Hainan power grid transmission line fault monitoring system. Morever, this paper proposes a new mothod of calculating the lightning attractive width by using electric geometry model. The calculation results are compared with regulation method and lightning detection data.At last, this papar researchs the mothod of calculating lightning striking rate on poles which takes probability distribution of lightning current amplitude and ground elevation into account. And the calculation results are compared to lightning detection data in Hainan. What is more, this paper builts models of towers used to analyze back striking lightning withstand level in ATP-EMTP, which indicates that it is not reasonable to take attention to lightning strokes on towers only in lightning protection calculation.