Design Of Distributed Seismic Survey System Based On Power Line Communication And Frequency Band Expansion

Seismic exploration technology can help to obtain the basic characteristics and specific forms of underground strata,and has an extremely wide range of applications in practical engineering fields such as mine,oil and gas exploration.At present,the data transmission system of distributed seismic survey system at home and abroad is usually wired transmission or mixed transmission,both of which need data transmission cable.However,the data transmission cable can't transport power,so it can only lay additional power transmission line or install lithium battery in each acquisition node,which leads to the problems of overweight cable,increased cost and frequent charging of lithium battery.In view of these problems,this paper puts forward the design scheme of distributed seismograph based on power line communication.The power line communication technology can couple the signal to the power line for transmission.When the power line continuously transmits power,it also transmits the signal,so there is no need for additional wiring;At the same time,all the acquisition nodes can directly obtain the required power supply voltage from the power line through the corresponding power circuit,so as to realize the battery free power supply of the acquisition node.This paper focuses on the implementation of distributed seismograph based on power communication,including the design and implementation of digital geophone,power communication unit,power circuit and human-computer interaction software.The key technical difficulties and solutions are as follows:(1)In order to solve the problem of weak response of electromagnetic induction analog geophone in digital geophone to low-frequency seismic signal,the design idea of frequency band expansion based on analog zero pole compensation method is proposed,and the simulation model is constructed by Tina for test analysis and verification;(2)Aiming at the software design of analog-to-digital conversion circuit based on STM32 control and Ethernet transmission in digital geophone,by adding multitask Free RTOS real-time operating system and adopting efficient UDP protocol,the parallel execution and high-speed transmission of data information storage and upload are realized;(3)Aiming at the reliability problem of data transmission on power line,a communication reliability guarantee mechanism is added to the power line communication unit to ensure the reliable transmission of seismic data in complex power line channel based on32-bit high-performance carrier chip;(4)In order to fully realize the battery free operation of the system and meet the requirements of different power supply voltages,a power chip with adjustable output voltage,large output current and high conversion efficiency is adopted to complete the hardware design and implementation of the power supply circuit.(5)The intelligent human-computer interactive interface is designed to realize the detection of connection state of acquisition node,quick setting of ad parameters,intelligent acquisition and fast storage of seismic data.Finally,the basic functions and the whole system of the distributed seismic survey system are tested.The test results show that the natural frequency of the analog geophone can be extended from 60 Hz to 10 Hz by the band expansion circuit;The system can complete the real-time synchronous acquisition of seismic data,and can realize the high-speed and reliable transmission of seismic data by power line as well as the transmission of power for the system.