Research On Key Technologies Of Distribution Network Terminal Data Remote Transmission Based On ARM And WLAN In Oil Field

Distribution systems in oil field have the characteristics of complex structure, disperse position, large variable load, big exhausted power for producing one ton of oil, weak real-time performance of data acquisition of distribution network terminals. Key technologies of distribution network terminal data remote transmission based on ARM and WLAN in oil filed is researched, in order to improve information management of distribution system of oil field, and optimize operation of the system. The main contents include:1. Appointing to the present condition, weak real-time performance of data acquisition of distribution network terminals in oil field, embedded data acquisition system based on ARM7 LPC2210 processor as hardware platform is researched, Wireless communication chip BWG200 based on WLAN, RS232 interface are expanded, so that the acquisition system can transmit data through WLAN, and the problem of electric energy measurement of distribution network terminals in oil filed is solved, and the real time and safety of data acquisition are improved.2. Appointing to the problem of slow data transmission speed and high cost in the oil field, power data wireless transmission system of oil filed is analyzed in the aspect of network protocol, topology structure, transmission mode, optimization of access point (AP) position and account, etc. AP optimization algorithm based on genetic simulated annealing algorithm is proposed, so that it avoids the low speed shortcoming of annealing algorithm, and prevents the premature convergence problem of genetic algorithm. In order to optimize the performance of transmission networks, transmission system is modeled and simulated with OPNET network simulation platform.3. In order to improve throughput of distribution network terminal data transmission system in oil field, and reduce network delay, channel allocation mechanism of WLAN MAC layer is researched. Adaptive algorithm of DCF protocol and scheduler algorithm of PCF protocol real time service with higher priority are analyzed. By analyzing the performance of DCF and PCF, contention window when workstations transmit the data frame and backoff mechanism when collisions happen are improved. WLAN throughput and delay service performances are researched in the mechanisms of DCF, PCF and DCF/PCF, system contention window and backoff exponential parameter are optimized.4. In order to improve the quality of distribution terminal data transmission, Turbo code of the third generation mobile communication system is as channel coding. An improved decoding algorithm with fading factor is proposed by analyzing the optimized decoding algorithm of Turbo code(MAP algorithm and its improved algorithm in logarithm domain). Simulation results show that the decoding algorithm can improve the decoding performance of Turbo code. Turbo code is improved for WLAN in the aspect of frame length, code rate, decoding algorithm, interlever, etc. The impact on Turbo code performances when the relevant parameters changed is analyzed by simulation. The transmission quality of WLAN is improved, comparing with convolution code widely used in conventional WLAN.5. Appointing to the security question of present wireless transmission network, TNC hyperchaos system is used in distribution network terminal data transmission in oil filed for secure communication. An improved hyperchaos array encryption algorithm is proposed, which is robust to the attack of exhaustive method. Sub-Nyquist sampling interval is used to enlarge the key space, which is robust to the attack of nonlinear reorganization. The encryption and decryption of the algorithm is realized by simulation, which has advantages of faster encryption ratio, easier implementation by software, larger key space, etc.Through the research on key technologies of distribution network terminal data remote transmission based on ARM and WLAN in oil filed, the problems of data acquisition and wireless transmission of mobile substations in oil filed are solved properly, which can provide reliable basis for reducing energy consumption of distribution system in oil field.