Gu Shanqiang

Research on Differentiated Lightning Protection Comprehensive Management for the 500-kV Power Network in the Area Near the Three Gorges Project

For the serious problem on lightning disaster risk of the Three Gorges outgoing lines, new technology, which is based on risk assessment, has been proposed for the lightning disaster defense for transmission lines. In order to realize lightning disaster risk assessment and defense technology, the procedure consists of analysis on lightning activity characteristics, lightning failures replay analysis, lightning disaster risk assessment, establishment and implement of lightning protection improvement, and practical defense effect assessment of lightning protection improvement. Implied on the lightning disaster defense for the Three Gorges outgoing lines, this technology has been verified with positive results. The widespread use of this technology would provide technical support for the differentiation design and improvement of lightning protection for transmission lines and for realizing the meticulous lightning protection in the management of transmission lines.

A lightning motion prediction technology based on spatial clustering method

Lightning warning is an essential means and a key technology for lightning disaster reduction. Passivity is the main drawback of existing lightning warning methods. This paper present a lightning prediction technology based on spatial clustering method to predict lightning motion by utilizing realtime and historical lightning monitoring data of lightning location system. On the contrary to the existing passive lightning prediction and warning methods, this technology initiatively predicts the prospective lighting area. The independent, discrete, random-happen flashes are aggregated to different thunderstorm groups similar to thunderclouds by the spatial clustering method presented in this paper. The position prediction of lightning can be achieved by tracking these thunderstorm groups and calculating the movement direction and speed of them. The lightning prediction method is applied to a certain region of central China. The experiment result shows that the predicted and real positions of lightning are approximately consistent. The average prediction accuracy is around 75%. Important support will be provided for improving the accuracy and reducing the false alarm rate of lightning warning by the presented technology.

Analysis of magnetic fields radiated by lightning strikes to a building

Almost all modern buildings use steel mesh, when a large current occurs nearby, such as a lightning return stroke happens, for the law of electromagnetic induction, electromagnetic fields generated by the lightning would certainly be affected. In general case, lightning detection stations are generally placed near the buildings, so the received signal would be affected by the buildings nearby. In this paper, we use FEKO to make geometric models of buildings, with MOM method to calculate whether or how the buildings impact the lightning magnetic field radiation.

Research on the differentiation technology of lightning protection for 220kV typical transmission line in the Three Gorges Area

There are complicated climate and geographical environment in the Three Georges Area. Besides, there are frequently lightning activities in this area. Therefore, the lightning protection performance of transmission line is very weak. In order to improve power supply stable and reliable, it is very important to improve the evaluation and rebuilding levels of lightning protection for transmission lines. This paper researches on the lightning protection of 220kV typical transmission line based on differentiation technology and strategy of lightning protection. In detail, analyzing the differences of lightning activities, terrains and topographic features, lines structures and insulation configurations, lightning risk can be evaluated. Then, differentiation scheme of lightning protection can be proposed based on evaluation result.

Application of lightning optical path monitoring system on 500kV transmission lines in mountain area

In order to obtain optical path photographs of lightning strike with a higher resolution, providing the necessary technical means for the accurate identification of 500kV transmission line lightning fault in mountain area, we developed an embedded, low-power remote online Lightning Optical Path Monitoring System based on 3G communication technology. Then, a case containing a lightning which struck the transmission line was analyzed in this paper combined with the results of the Lightning Optical Path Monitoring System, State Grid Lightning Location System and the Transmission Line Distributed Fault Diagnosis System.

Lightning imaging with thunder using broadband direction-of-arrival estimation technique

A single-station-based three-dimensional (3D) acoustic lighting mapping system comprising a microphone array has been developed and used for lightning observations, in which a new broadband direction-of-arrival (DOA) estimation techniques namely incoherent signal-subspace method are proposed for thunder signals in the far-field. Two cloud-to-ground (CG) flashes with highly branch channels recorded by the system are analyzed and presented in this paper. The acoustic mapping results can not only locate on the main channel produced by the return stroke process but also depict the branch channels. Moreover, the located thunder sources by the mapping system and the photography of the high speed camera agree well with each other demonstrating the effectiveness and correctness of the estimation techniques and the mapping system.

The recognition method of thunder based on a noise-estimation algorithm for highly non-stationary environments

A recognition method of the thunder signal based on the end-point detection method with a noise-estimation algorithm for highly non-stationary environments is proposed. To determine the parameter of the algorithm and verify the effectiveness and accuracy of the method we analyze the acoustic signals obtained from two microphone arrays installed at the top platform on a seven-floor building in Wuhan. In this paper, we have chosen two acoustic signals to test the endpoint detection method. It is revealed from the recognition result that the method can find out the accurate beginning and ending time of the thunder signal from the acoustic signals.

Calculation of lightning trip-out rates for 10 kV overhead distribution line

The insulation level of 10 kV overhead distribution line is relatively low with high flashover rate. This paper analyzes the lightning performance of direct lightning by using ATP-EMTP. Basing on EGM model, attract range and lightning trip-out rates of direct lightning is calculated. The coupling model proposed by Agrawal and finite difference time domain (FDTD) method were used to calculate the indirect lightning overvoltage due to the nearby lightning. Meanwhile, the lightning trip-out rates of induced was also calculated by interval statistical method. The numerical method was verified by comparing with a reference. The simulation calculating results showed that indirect lightning trip-out rates take up more than 80 percent of the total lightning fault.

Research on the replay analysis of lightning shielding failure under conditions of complex landscape in a mountainous area

In order to improve the performance of technology and economy for improvement of lightning protection, the lightning flashover faults should be analyzed carefully. Aiming at the lightning flashovers in mountainous area, there was no effective method to discriminate the fault property for the operation department. Apparently, nor can the range of lightning shielding failure be determined. This paper proposed the calculation of lightning protection performance to simulate the status of the fault time, based on the lightning detection data, and the accurately topography and geomorphology data acquired by 3 dimensional GIS. Through this simulation method, the fault property and the range of lightning shielding failure can be obtained. This method has been verified by the typical fault. The analysis result can be applied to the improvement of lightning protection.