WTEM高速关断瞬变电磁探测系统

WTEM fast turn-off transient electromagnetic detection system

瞬变电磁测量系统是一种用于地质结构探测的地球物理探测设备,在大功率电流陡脉冲发射、高精度同步控制、大动态范围信号采集等方面,尚有许多亟待解决的问题。本文提出了一种瞬变电磁测量系统,提出了恒压钳位高速关断电路,具有关断延时短、电流下降沿线性度高和发射电流大的特点,并加速了电流的上升,改善了一次场质量;采用蓝牙技术,实现了对接收机的无线操控,改善了系统操控性能;设计了GPS同步控制器,采用温补晶振与GPS协同工作的方式,解决了GPS短时间失效的问题。在山东输油管道腐蚀探测工程中,WTEM系统做了野外和室内实验,测试表明,WTEM系统轻便、操作容易,退饱和的速度也较快,反映浅层地质信息的能力强。

Transient electromagnetic measurement system is a kind of geophysics prospecting devices, which is used in geological structure survey. In the aspects of current steep pulse transmission, high-power, high precision control, large dynamic range signal acquisition and so on, there are still a lot of problems to be solved urgently. This paper proposes a novel extra fast turn-off transient electromagnetic measurement system, analyzes its principle, structure and system characteristic. The system adopts an extra fast turn-off circuit, which has the characteristics of short turnoff time, high linearity of current falling-edge and high transmission current. The quality of primary field and the resolving power for superficial detection are improved. Bluetooth technology is adopted to realize wireless control of the receiver and the control performance of the system is improved. The GPS synchronous controller is designed. A temperature compensated crystal is adopted to work with GPS in coordination, and the GPS short-term invalidation problem is solved. In the Shandong oil pipeline corrosion survey project, a comparison test between WTEM and GDP32 from ZONGE Company of U. S. A was carried out. The results indicate that WTEM system is easy to carry, convenient to operate, and has even faster saturation retreating pace and better ability to reflect the geological information in shallow layers, which concludes that WTEM system has excellent performance.