A Design Of Secure Monitoring Terminal Based On Domestic Chip

Power system automation is the direction the power system has been making efforts to achieve. Power system automation includes power generation control automation, power dispatching automation and distribution automation. Distribution of power system is an important part which faces to power users directly. Whether the power system can run safely and smoothly depends on the performances and quality of distribution automation equipment.This paper studies the key technology of remote terminal in the background of development of a distribution automation remote terminal. We complete design of the high-performance secure RTU(Remote Terminal Unit), which is based on the independent control domestic chip, and has the function of data encryption transmission.This paper introduces the basic function, application environment and relevant national electric power industry standard of secure RTU first. Then gives the overall design scheme of secure RTU, and focuses on the core processors- the Longxin 1Bprocessor. The processor is developed by Institute of Computing Technology, Chinese Academy of Science(ICT). Paper introduces the basic parameters, internal resources and interfaces. and selects a high precision 16 bit ADC, designs suitable ac sampling circuit to improve the sampling accuracy and reduce the electricity parameter error.Secondly, the paper introduces two methods of sampling method: the DC-sampling and AC-sampling. And analysis the advantages and disadvantages of two methods, then determine to choose the AC-sampling as the sampling method of secure RTU. Then AC-sampling is introduced seriously, including the sinusoidal model algorithm and nonsinusoidal periodic model algorithm. The sinusoidal model contains the maximum algorithm, single point algorithm, half cycle integral algorithm, two points sampling algorithm, etc.; Non sinusoidal model algorithm contains root-mean-square algorithm, Fourier algorithm. And designs the signal conditioning circuit, switch input and output circuit, use the MATLAB and Multisim to simulate Fourier algorithm and circuits.Then the paper introduces two communication interface of secure RTU, two kinds of communication protocols: 101 protocols and 104 protocols. Two protocols correspond to two communication interfaces. One is RS485 interface communication mode. Serial communication mode Modbus communication protocol is also introduced, and analysis the Modbus communication protocol data frame format, instances examples of the Modbus communication protocol used in the function of secure RTU. Another kind is the Ethernet interface communication mode, introduces the Modbus/TCP protocol. Ethernet communication interface can realize more quickly, more stable, and long distance transmission.This paper introduces the cipher system of secure RTU which uses the GMB algorithm to encrypt data with its own function and significance of the data encryption transmission. The paper also introduces some GMB algorithms: SM1, SM2, SM3, SM4 algorithm, including the basic principle and function of each algorithm..Simulation test shows that secure RTU has a high degree of power parameter which its error size can be controlled in the requirement named DL/T 721-2013 distribution automation remote terminal and better real-time performance.In the caught testing, data can transfer in cipher text in the VPN tunnel, which meets the design requirements well.