摘 要

激光诱导击穿光谱法（LIBS）是一种崭新的光谱分析方法，把LIBS技术应用于真空断路器真空度在线检测也是具有创新性的应用。相较于现有的真空度检测技术，该方法有简单便携、准确度高、样品损伤小等很多优点，具有很大的发展利用价值。该装置接收CuⅠ521nm和OⅠ777nm的光谱信号，对信号进行转换处理以得到其峰值，通过比对Cu和O元素的峰值比和实验准确数据即可获得待测样品的真空度。系统主要由光电倍增管、I/V转换、峰值保持、采样处理等模块组成。

首先根据LIBS技术的原理，选取高灵敏度的光电倍增管作为LIBS光谱信号的传感器。然后，根据光电倍增管的特性设计了1000V的高压偏置电路和I/V转换电路，将检测到的信号转换为易处理的电压信号。由于LIBS技术所用的是窄脉冲激光，经过光电倍增管产生的电压信号也是窄脉冲信号，所以利用宽带运算跨导放大器和缓冲器OPA860实现峰值保持的功能，利用Multisim仿真来验证OPA860的峰值保持性能。结果表明纳秒级的窄脉冲信号经过峰值保持后可保持数微秒，易于被单片机采样。而单片机选用高性能低功耗的STM32F4芯片，数据经过一阶滞后低通滤波之后通过串口把数据送到液晶显示屏中来显示结果。经模拟实验和软件测试后，结果可以很好的反应该装置接收的光信号，且误差很小。

该装置是基于LIBS技术的检测装置，而真空度测量就对装置的透光性和抗干扰要求较高。可对于做进一步改进，之后用于实际生产中来检测真空度的前景很广阔，有利于检测成本的降低和电力系统的稳定运行。

关键词：断路器真空度；LIBS；在线检测；峰值保持

Abstract

Laser induced breakdown spectroscopy (LIBS) is a new method of spectral analysis. It is also an innovative application to apply LIBS technology to vacuum detection of vacuum circuit breaker. Compared with the existing vacuum detection technology, this method has the advantages of simple and portable, high accuracy, small damage to the sample and so on, and has great development and utilization value. The device receives the spectral signals of CuI 521 nm and O7 777nm, and converts the signal to obtain its peak value. The vacuum degree of the sample to be measured can be obtained by comparing the peak ratio of Cu and O element and the experimental data. The system is composed of photomultiplier tube, I / V conversion, peak hold, sampling processing and other modules.

First of all, according to the usage of LIBS technology, the high sensitivity of the photomultiplier tube is selected as the LIBS spectral signal sensor. Then, the characteristics and work requirements of the photomultiplier tube design of the high-voltage bias circuit and I / V conversion circuit, the detected signal is converted to easy to handle the voltage signal. As a narrow pulse laser used in the LIBS technology, the voltage signal generated by the photomultiplier tube is also a narrow pulse signal, so this paper uses broadband operation transconductance amplifier and buffer OPA860 to achieve peak hold function. The result shows that nanosecond narrow pulse signal through the peak can maintain a few microseconds, and it is easy to be single-chip sampling. To the single-chip, high-performance low-power STM32F4 chip is choosed. The data is sent to the LCD to display the results through the serial port. After the simulation experiment and software test, the result can be a good response to the device to receive the optical signal, and the error is very small.

The device is based on LIBS technology detection device, and vacuum measurement of the device on the light transmission and anti-interference requirements are higher. The device can be made for further improvement, and the actual production to detect the vacuum is very broad.It is beneficial to the detection cost reduction and the stable operation of the power system.

Key Words： vacuum breaker ; LIBS; on-line detection; peak hold

目 录

第1章 绪论 1

1.1 课题研究背景及意义 1

1.1.1 真空断路器发展状况 1

1.1.2 真空断路器的结构特点 3

1.1.3 真空度检测意义 3

1.2 在线检测真空度国内外研究现状 5

1.3 本文主要研究内容 7

第2章 LIBS法原理介绍 9

2.1 原理简介 9

2.2 实验装置介绍 9

第3章 真空度在线检测信号处理系统的硬件实现 11

3.1 光电倍增管及其高压偏置电路 11

3.2 光电倍增管信号输出电路 13

3.2.1 I/V转换电路 14

3.2.2 电压放大电路 15

3.2.3 减小干扰的措施 16

3.3 峰值保持电路 16

3.3.1 电路工作原理 16

3.3.2 芯片选型 18

3.3.3 电路仿真 19

3.3.4 电路设计 22

3.4 单片机及其外围电路 23

3.5 稳压电路 25

第4章 真空度在线检测信号处理系统的软件实现 27

4.1 软件整体设计 27

4.1.1 软件开发环境介绍 27

4.1.2 需求分析 27

4.2 单片机程序 27

4.2.1 单片机基本配置 28

4.2.2 A/D转换模块 29

4.2.3 滤波算法 30

4.2.4 串口通信模块 32

4.2.5 液晶显示模块 33

第5章 真空度在线检测信号处理系统的实验验证 35

5.1 硬件模拟测试 35

5.2 软件测试 36

第6章 结论与展望 37

6.1 主要结论 37

6.2 后续研究工作的展望 37

参考文献 39

致 谢 42

第1章 绪论

1.1 课题研究背景及意义

在电力系统中，由发电机、高压输电线缆、变压器、电抗器、绝缘子和断路器等主要设备组成一个电网。在电网中，各种电力设备都有其重要的作用。断路器起到的作用有：

（1）在正常情况下起控制作用，具体是关合、承载和开断电流；

（2）当电路发生故障时，火线和零线接触导致短路、瞬间电流极大或者工作电流超过额定负载电流时，断路器跳闸，从电网中切除故障部分，保护正常电路，起到短路保护和过载保护的作用；