Implementation Of Fault Detection And Timing System In Lightning Location System Based On FPGA

In daily life,lightning is a natural disaster that is very common everywhere,and the huge energy it releases often affects the normal operation of the national transmission network.Due to the limitation of economic costs and other factors,many transmission lines in China are in the state of bare wires,and they are exposed to the outside world all the year round.The faults caused by lightning strikes account for more than 50% of the causes of tripping.This has become a major problem in the power system.Therefore,a solution that can quickly and accurately find the location of a lightning strike fault plays a vital role in ensuring the stable operation of the power supply system.In order to analyze and design the lightning positioning system more clearly,this paper first introduces the development background and significance of lightning positioning system,digital down conversion technology and precise time calibration technology,finds the data and studies their current research status at home and abroad.Then in the second chapter and the third chapter,the basic theory of digital downconversion technology is analyzed in detail and the detailed design of the system is carried out,such as integral cascade filter and finite impulse response digital filter.At the same time,in the fourth chapter,the characteristics of the precise time calibration technology are studied,and the design of the timing system is carried out.In the fifth chapter,using vivado and modesim software to implement the specific hardware circuit,and write the corresponding functional program,the design requirements into the actual code and circuit structure.In addition,accurate simulation tests and functional debugging were performed for the programs written.Finally,the content of the work of this thesis is summarized and the improvements in the design are proposed.In this paper,we use time difference positioning technology(TOA),analog-todigital conversion technology,digital down conversion technology,signal processing technology and clock synchronization technology to design a system that can monitor transmission lines in real time and accurately time the lightning strikes.The system can continuously monitor the magnetic field condition of the transmission line.When a certain part is affected by lightning strikes,the surrounding magnetic field will change immediately.At this time,the digital information received in the FPGA is converted by analog-to-digital conversion.A fault spike will occur immediately.Through the energy threshold detection,combined with the accurate PPS seconds pulse in the GPS,accurate timing can be given to the received fault spikes.The lightning strike measuring stations around the country can accurately calculate the location of the lightning strikes based on this,and timely and quickly repair the faults to ensure the stable operation of the transmission network.Through the lightning detection system of various places,according to the constant stability of GPS and the short-term stability of the constant temperature crystal,the error time of lightning failure can be controlled to 100 ns,and the corresponding geographical error is 30 meters.This result is quite accurate and can ensure that the troubleshooters quickly find the fault.