Online insulation monitoring technology for a marine controlled source electromagnetic transmitter system
DENG Ming1,2(), WANG Meng1,2(), WU Wen1,2, MA Xiao-Xi1,2, LUO Xian-Hu3
1. School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China 2. State Key Laboratory of Geological Process and Mineral Resources,China University of Geosciences (Beijing), Beijing 100083, China 3. Guangzhou Marine Geological Survey, Guangzhou 510075, China
The marine controlled source electromagnetic (MCSEM) method is widely used in the exploration of natural gas hydrate, seabed oil and gas resources, and seabed geological structures. In the process of marine operation, the shipborne power supply unit transmits high-voltage and high-power electric power to a marine controlled source electromagnetic transmitter on the seabed through deep towing cables, during which it is necessary to carry out the automatic and real-time measurement and monitoring of the insulation resistance in the high-voltage power supply circuit to ensure the safe transmission of electric energy and timely deal with the abnormal power supply. This study collected the leakage current between the high-pressure end and the ground using high-voltage broadband couplers, insulation detection modules, remote data transmission units, and PC monitoring software. Meanwhile, this study amplified the leakage current using an analog amplifier and then calculated the insulation resistance by measuring voltage, thus achieving the automatic measurement and monitoring of the insulation resistance between the high voltage circuit and the ground. As verified by offshore tests, the automatic online insulation monitoring technology can meet the requirements of the MCSEM system and achieve the ideal online evaluation of the insulation performance of the system, thus providing a useful reference for the research and development of similar functions of marine instruments.
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