Lightning Three-dimensional Electric Field Data Acquisition And Analysis

Lightning is a universal phenomenon in nature, when lightning occurs, it often has a great threat to construction, electrical and electronic equipment and human social life.Therefore, it is very significant to study the formation mechanism, the evolution regularity and the early warning of lightning. Collecting the electric field data while lighning occurs is an important method of studying the characteristics of lightning. When lightning occurs, the magnitude and direction of the atmospheric electric field will change dramatically.In lightning research, detecting the rapid changes in the electric field while lightning occurs is necessary, and sometimes multi-point simultaneous data acquisition in the wild environment is needed. While,the detecting direction of many current measurement systems is parallel or perpendicular with the spindle direction of their sensors,which only can realize the one-dimensional electric field measurement,and can not completely accurate analyse the characteristics of lightning electric field.What’s more,the traditional high-speed data acquisition systems are based on PCI,they have a variety of limitation,such as large volume,high dissipation,high cost and can not be applied to multi-point simultaneous data acquisition outdoors.In order to analyze the rapid change process of electric field while lightning occurs, the influences of lightning on various kinds of electrical and electronics equipment, and the influences of different terrains for lightning electric field more comprehensively. In this paper we design a miniaturization of lightning three-dimensional electric field data acquisition system.The system can be used for lightning electric field three-dimensional measurementand is suitablele for multi-point synchronous data acquisition outdoors. The system equips three metal bars as sensors,FPGA is used as the core control chip to control the system to collect data, transfer data and store data in order to improve system performance and increase data processing speed, and two AD9248 are used to complete three-way synchronous data acquisition. The system store and transfer data through SDRAM memory and USB interface, which can transfer data to the PC through the USB to display, storage and analysis.The paper first finishes the system’s hardware design.The hardware of the system includes the electric field sensor module, signal conditioning circuit module, high-speed A/D converter module, FPGA control module, SDRAM memory module and USB transmission module. Then, the software of the system is designed, including the design of the FPGA logic via Verilog, the design of USB firmware and USB drive and the design of the application program in PC.Experiments results show that, the system can realize synchronous data acquisition for lightning three-dimensional electric field.,and it can effectively measure the rapid change process of atmospheric electric field at frequencies up to 5MHz bandwidth,and acquisition speed up to 20MSPS.Meanwhile,the system has the advantages of low cost, miniaturization and easy to use. It provides instrumental protection for the study of lightning processes and mechanisms.