智能电网输电线路在线监测系统的设计与实现.docx

智能电网输电线路在线监测系统的设计与实现 伴随着科学技术发展，工农业用电需求日益增长，现有输电线路已经不能满足电 能的有效传输。智能电网的研究与建设受到各个国家的重视，我国已经制定智能电网 综合发展战略方案。我国的智能电网战略以国家电网公司的坚强智能电网为基础。电 力系统是由发电、输电、用电、变电、调度等子系统组成的复杂系统，输电线是连接 电力系统各个子模块的血管。输电线路的运行故障状态决定电能的输送，因此输电线 路故障的在线监测将是电网未来发展的必然要求。目前输电线路故障的在线监测已经 成为国内外研究热点，不同的监测方案被纷纷提出。传统的故障检测算法基于稳态分 量。但是稳态分量法因为其固有的缺点造成实际精度不高。 本文首先分析了小电流接地系统的短路，接地和断路故障；然后研究了小波变换 在信号奇异性分析中的应用，设计了一种基于小波变换的新型输电线路故障检测算法； 最后研制了在线监测系统的硬件系统和软件系统。并在实验室条件下对系统各个模块 进行测试以及系统联合调试。主要内容如下： 分析了输电线路故障检测的当前主要状况，分为检测算法和检测设备两方面。经 典的检测算法有：零序电流比幅法，零序电流相位法，群体比幅比相法，神经网络法， 模糊理论选线法，五次谐波法和Prony分析法等。检测设备主要有：馈线自动化终端， 故障指示器。 分析了输电线路的基本电路模型，发生故障时输电线路电流电压的变化，短路故 障和接地故障发生时电路中的电流瞬间变化情况和稳定后的状态。其中电路基本模型 中分析了输电线路的电阻、电容、电感和输电线的中长传输线模型。并分析了对称分 量法的基本原理。研究了零序电流在故障发生的时候的分布情况；在Matlab的电力实 验箱中搭建一个小型电力系统，使用该系统仿真产生接地和短路故障，输出故障信号， 并对信号进行分析。该故障仿真系统在后续的系统联调中提供故障信号。 分析小波变换的基本思想，包括小波变换相对于傅里叶变换的优点和连续小波变 换。以计算机实现小波变换为目的，分析了尺度的离散化、多分辨率分析和滤波器组 法的小波变换实现；结合小波变换对信号奇异性指数李氏指数进行研究分析；设计一 种基于小波变换的故障监测算法，该算法利用了故障线路的零序电流特点和小波变换 在信号奇异性分析中的应用。并在Matlab中进行仿真分析，仿真结果表明了该检测算 法的有效性。 基于嵌入式计算机技术，对输电线路故障监测系统进行了总体设计，设计了 TMS320F2812配合S3C2440的双CPU总体架构。ARM和DSP之间的通信使用CAN总 线，上位机软件在 labview 环境下实现。此外给出了系统各个模块的硬件原理设计， 主要包括芯片选型和原理图设计等。 按照软件工程基本步骤，对系统的软件功能进行分析，然后对系统进行模块化的 软件设计，主要包括 DSP 数据处理系统的软件设计、ARM 系统的软件设计和上位机 监测软件的软件设计，并给出主要程序的流程图和部分程序源码等。其中 DSP 系统主 要包括ADC采样系统程序，基于DSP的小波变换程序、TMS320F2812的eCAN通信程序 和DSP。 在实验室条件下，基于实验开发平台进行系统主要模块测试，包括信号调理电路 的测试、基于DSP的小波变换测试、AD采样测试和CAN通信测试，然后使用Matlab 建立的电力仿真系统产生故障信号，进行系统联合测试。实验测试表明，本文研制的 在线监测系统工作稳定，达到设计要求。 本论文的研究是在实验室条件下进行的，硬件系统是基于开放平台实现的，故障 信号源是取自matlab仿真，下一步工作需要在实际现场进行测试。 关键词 智能电网；输电线路故障；故障在线监测；小波变换；嵌入式技术 Design and Implementation of Smart Grid Transmission Line Online Monitoring System Abstract With the rapid development of science and technology, the electric power consumption of industrial and agriculture rises sharply. The existing power grid can no longer meet the demands of electric energy transmission. While the smart grid has been widely studied and built by most countries, strategies for developing smart grid are work out by national relevant departments. The strategies of our country are based on strong smart grid by STATE GRID Corporation. Electric power system consists of generation, transmission, using, transforming and dispatching subsystem. Transmission line is vessel of electric power system. Online monitoring of transmission line is the requirement of grid in the future, because statues of transmission lines will affect the transmission of electric energy. As the online monitoring technology of transmission is a hot research point in the world, many different methods are proposed. The classical fault detection algorithms are based on state component. These algorithms have their intrinsic limitations. In this paper, the short, earth and open fault has been analyzed at first. The application of wavelet transform in singular analysis has been researched and a fault detection algorithm based on wavelet transform has been designed secondly. The hardware and software of online monitoring system has been designed at last. The whole system has been tested in laboratory. Main works of this paper are as follows. The research status of transmission line fault diction has been analysis. The classical fault detection algorithm such as zero serial current amplitude, zero serial current phase, amplitude-phase, neural network, fuzzy, fifth harmonics and Prony analysis algorithm are based on state components.The Feeder Terminal Unit and fault indicator are main diction equipment. The model of transmission line, the change of current and voltage when fault happen and the transient and stable state have been analyzed. The resist, capacity, inductance, medium line model and symmetrical component method have been analyzed. The feature of zero sequence current has been analyzed. The power transmission line faults were simulated with the Simulink of Matlab. The result of simulation has been analyzed. The simulation system will been used to provide fault signal in system testing. The based ideal of wavelet transform has been research. The Fourier Transform and Wavelet Transform have been compared. In order to implement wavelet transform on computers, the discrete wavelet transform, the multiresolution analysis and subband filtering has been studied. An algorithm to monitor transmission status was designed on base of signal singularity analysis with wavelet theory and the feature of zero sequence current. The algorithm has been proved by simulation on Matlab. The system design of the online monitoring system has been described. The architecture of dual CPU based on TMS320F2812 and S3C2440 has been proposed. The chips were selected. The schematics were designed. The ARM system and DSP system are connected by CAN bus. The computer monitor software was designed by labview. Software requirements were analysed based on principle of software engineering. The software of signal process system based on DSP, communication system base on ARM and monitoring software based on Labview was designed. The main flowcharts of software and codes are presented. The DSP system software consist of ADC sampling program, wavelet transform based DSP, CAN communication based on TMS320F2812 eCAN and main program of DSP. The signal conditioning circuit, the implementation of wavelet transform based DSP ， AD sampling and communication between DSP and ARM have been tested in lab. The functions of system have been tested based on the fault signal produced by Simulation in Matlab. The result of testing proved that system designed can work effectively and stably. The system should been tested in industrial field because the system designed in this paper is in laboratory, the hardware is based on experiment platform and the fault signal is from simulation system. Keywords: Smart Grid; Transmission Line Fault; Online Monitor; Wavelet Transform; Embedded Technology 目录 目 录 摘 要 . I Abstract.III 第1章 绪论 . 1 1.1 研究背景及意义. 1 1.2 研究现状及发展趋势. 3 1.3 本文主要研究内容. 7 第2章 小电流接地系统故障分析与研究 . 9 2.1 输电线路基本模型和分析方法. 9 2.1.1 输电线基本电参数. 9 2.1.2 输电线的传输线模型.11 2.1.3 输电线非对称故障分析.11 2.2 故障稳态过程分析. 13 2.2.1 中性点不接地系统故障稳态分析. 13 2.2.2 中性点经消弧线圈接地系统故障稳态分析. 15 2.3 故障瞬时过程分析. 16 2.3.1 短路故障瞬时分析. 16 2.3.2 接地故障瞬时分析. 18 2.4基于Matlab的输电线路故障仿真 . 20 2.4.1电力故障仿真系统的建立. 21 2.4.2单相接地短路仿真. 22 2.4.3三相短路接地仿真. 24 2.5 本章小结. 25 第3章 基于小波变换的输电线路故障诊断研究 . 27 3.1 小波变换. 27 3.1.1 连续小波变换. 27 3.1.2 小波变换尺度离散化. 28 3.1.3 多分辨率分析. 29 3.1.4 信号奇异性分析. 31 3.2 基于小波变换的输电线路故障检测算法设计. 34 3.2.1小波基的选取. 34 3.3.2算法设计. 34 3.3 基于小波变换的输电线路故障检测算法Matlab 仿真 . 37 3.3.1 输电线路单相接地故障的仿真. 37 3.3.2 输电线路相间短路接地故障的仿真. 39 3.4 本章小结. 40 第4章 在线监测系统总体设计和硬件设计 . 41 4.1 系统总体设计. 41 4.1.1监测系统基本特性. 41 4.1.2总体设计. 42 4.2 ARM系统硬件设计 . 43 V 江苏科技大学工学硕士学位论文 4.2.1 ARM 最小工作系统设计 .43 4.2.2 电平转换电路 .47 4.2.3 UART接口电路.47 4.2.4 LCD液晶显示器接口电路设计 .48 4.2.5 GPRS通信模块 .49 4.3 DSP信号处理系统硬件设计 .50 4.3.1 DSP最小工作系统设计 .50 4.3.2 信号调理电路设计 .53 4.4 基于MCP2515的CAN通信接口电路设计 .54 4.4.1 芯片选型 .54 4.4.2 接口电路 .54 4.5 本章小结 .55 第5章 系统软件设计 .56 5.1 系统软件功能分析 .56 5.1.1 DSP数据处理系统软件功能分析 .56 5.1.2 ARM系统功能分析 .56 5.1.3 上位机监测系统功能分析 .57 5.2 DSP数据处理系统软件设计 .57 5.2.1 ADC采样程序设计 .57 5.2.2基于DSP的小波变换程序设计 .59 5.2.3 TMS320F2812的eCAN通信程序设计.60 5.2.4 DSP主程序设计 .62 5.3 ARM系统软件设计 .63 5.3.1嵌入式Linux系统的构建 .63 5.3.2嵌入式Linux设备驱动程序的设计 .67 5.3.3应用程序的设计 .70 5.4 上位机监测软件设计 .72 5.5本章小结 .73 第6章 实验测试 .74 6.1 实验测试平台 .74 6.2 信号调理电路调试 .74 6.3 DSP部分软件测试 .76 6.4 CAN通信测试 .77 6.5系统联调 .77 6.6本章小结 .81 总结与展望 .82 参考文献 .