The Research Of Subsea Bata Transmission Technology Based On Power Line Carrier

As the key equipmet of Marine oil and gas exploration, subsea production system has to work stable and reliable in order to guarantee the safety of subsea production. Subsea control system(SCM) can collect real-time process parameters of subsea production and transfer them to master center station(MCS). It realizes real-time monitoring of subsea production status. Power line carrier(PLC) communication depends on the power line transferring the data information, which is modulated into high frequency carrier and coupled on power line. Therefore, PLC communication transmission technology based on umbilical adapted to the working characteristics of subsea production system, which not only solve the problem of long distance transmission, also reduce the complexity of underwater wiring and saves the cost of production. However, the research of the application in subsea of PLC communication technology in China is at the beginning. In view of the underwater power carrier technology study, this paper obtained the following results:(1) This paper introduces the topology of the subsea production system and analyses the functionof the node modules, which are in the process of the PLC subsea transmission.Meanwhile, it summarizes the influence on subsea power carrier data transmission of umbilical, power supply EPU and the modulation of SCM. It concludes the difficulty of subsea PLC communication.(2) In this paper discusses PLC communication technology of the spread spectrum communication and orthogonal frequency division multiplexing(OFDM) and designs the the hardware circuit of subsea PLC data transmission system based on the chip spread spectrum phase-modulated carrier Mi200 e and main controller. Using SPI serial communication implements data transmission between the main controller chip and carrier chip. After QPSK modulation by Mi200 e, data through Mi200 e built-in power signal amplifying circuit and the design of narrow-band filtering coupling circuit, complete sending and receiving in the umbilical cord cable lines.(3) Based the analysis of communication protocol on chip Mi200 e, in detail designs the sending and receiving process. According to the transmission characteristics of the power supply network, using the zero crossing detection technology realizes continuous three sending packets within 10 ms half a period of in order to ensure the reliability of data transmission.(4) Test part adopts serial assistant software. Accroding to waveform analysis, adjust circuit parameters. The change of the load characteristics have a greater influence on the waveform amplitude, but waveform integrity, achieve the goal of the QPSK modulation.At last, the debugging of subsea data transmission system proves the feasibility of the design. The whole system realized 7 sensor signals collection with manifold tree model,accuracy 0.2F.S in current measurement.The testing through the system continuous running on the subsea testing flat, verify the stability and reliability of the system.