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Instructor: Yang Lijun Email: yljcqu@cqu Phone : 13883566037

局部放电及测量. Partial Discharge Detection. Bilingual Teaching Course. 主讲人 : 杨丽君. Instructor: Yang Lijun Email: yljcqu@cqu.edu.cn Phone : 13883566037. Before Beginning. 关于这门课程 About this Course. 双语教学( bilingual teaching ):. 定义 definition :. 部分或全部 采用 非母语形式 进行 非语言 学科的学习.

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Instructor: Yang Lijun Email: yljcqu@cqu Phone : 13883566037

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  1. 局部放电及测量 Partial Discharge Detection Bilingual Teaching Course 主讲人:杨丽君 Instructor: Yang Lijun Email: yljcqu@cqu.edu.cn Phone:13883566037

  2. Before Beginning 关于这门课程 About this Course 双语教学(bilingual teaching): 定义definition : 部分或全部采用非母语形式进行非语言学科的学习 在学得该学科专业知识的同时,应对基本专业外语进行学习 目的 goal: • 学习高压电气设备局部放电的产生机理,掌握各种设备的局部放电测试技术(主要目的!!); • 以英语作为第二语言,在学习学科专业知识过程中掌握与学科相关的基本专业外语(包括大部分专业词汇,学科知识概念和公式的表达及部分释义)。 以学习学科专业知识为主,以掌握基本专业外语词汇及释义为辅。

  3. Before Beginning 教学模式 teaching model: • 沉浸式 Immersion Bilingual Education: 适用于有很好目标语语言环境的学生和老师 • 维持母语式 Maintenance Model: 适用于已具备良好目标语能力的学生和老师,母语与外语较为灵活地互为主体语言 • 双语过渡式Transitional Bilingual Model: 适用于缺乏目标语环境 的群体;借助于母语作为理解和交流的工具,同时尽可能地扩大与目标语的接触,提高学生目标语能力。

  4. Textbook and References • [1] Kreuger, F.H., “Partial Discharge Detection in High-Voltage Equipment”. (Textbook) • [2]李剑,“局部放电测量”,讲义 (Reference) • [3]邱昌容,王乃庆. 《电工设备局部放电及其测试技术》. 机械工业出版社(Reference)

  5. Lecture 1 Introduction

  6. Contents • Basic Concepts of Partial Discharge • 2.Development of PD detection techniques • 3.Objects and main subjects 局部放电的基本概念 局部放电检测技术的发展 学习目的及主要内容

  7. 1. Basic Concepts of Partial Discharge 1.1 What is Partial Discharge Definition of PD Electric discharges that do not completely bridge theelectrode(电极) are called Partial Discharge (PD). 在电场作用下,导体间绝缘仅部分区域被击穿(没有贯穿施加电压的导体之间)的电气放电现象。

  8. 1. Basic Concepts of Partial Discharge 1.2 Why PD Occurs in High Voltage Equipment (1) Insulation Material and Structure in HV Equipments 高压电气设备的绝缘材料及结构 Belong to organic material(有机绝缘材料) In combined insulation structures(复合绝缘结构) the insulation materials commonly used in HV equipments (Please give some examples): Transformer (变压器): Mineral oil (矿物油), Kraft paper(牛皮纸), Pressboard (纸板),Epoxy resin(环氧树脂) Capacitor (电容器): Mineral oil , Kraft paper, Organic film(有机薄膜) Mineral oil, Kraft paper, PE(聚乙烯), XLPE (交联聚乙烯), EPR (乙丙胶) HV Cable (电缆): HV Electrical machine (电机): Epoxy(环氧) Insulator used in transmission line (输电线路绝缘子): Silicon (硅橡胶)

  9. 1. Basic Concepts of Partial Discharge (2) Factors lead to PD The breakdown strength of local area in insulation is reached. 绝缘体局部区域的电场强度达到击穿场强 Non-uniform Electric Field电场不均匀 Inhomogeneous Dielectric Medium电介质不均匀 Cavity and Impurity气泡和杂质 Four Cases of non-uniform Electrical Fields

  10. 1. Basic Concepts of Partial Discharge 1.3 Damages to Insulation by Partial Discharges (1) Bombardment of charged particle 带电质点轰击 Broke the chemical bond and damage molecular structure of insulation material .打断化学键和损坏分子结构 (2) Thermal Effect 热效应 High temperature of discharge point accelerates thermal damage to materials加速绝缘热劣化. (3) Resultant of Reaction 反应生成物 resultants, such as ozone, moisture, nitric acid, oxalic acid , erode materials腐蚀绝缘. (4) Radiation Effect 辐射效应 visible light, ultraviolet radiation, X-radial,γ-radial embrittle materials使绝缘脆化. (5) Mechanical Effect 机械效应 Successive blasting discharges result in high gas pressure and crack the materials使绝缘开裂.

  11. 1. Basic Concepts of Partial Discharge 1.4 Goals of PD Detection • Whether discharges are present or not at rated voltage? 额定电压下是否存在局部放电? • What is the magnitude of PD? 放电量的大小? • Whether permissible discharge magnitude is exceeded or not? 放电量是否超过了允许放电水平? • What are the inception and extinction voltages? 起始放电电压、熄灭电压是多少? • How about various PD characteristics? 各种放电特性如何?

  12. 2. Development of PD detection techniques 2.1 Characteristics of PD tests • A type of nondestructive control test : neglectable damage to insulation. 非破坏性试验 • A more sensitive tool to identify insulation defects in electrical devices comparing with voltage withstanding tests.灵敏度高,容易发现缺陷 • for new HV equipments, to find weaknesses of insulation, such as cavity, impurities.发现新设备的绝缘薄弱环节 • for equipment in service, to find the latent defects of insulation due to aging.发现运行设备绝缘由老化引起的潜在缺陷

  13. 2. Development of PD detection techniques 2.2 Basic Methods of PD Detection (1) Electrical Discharge Detection • Impulse Current Method, ERA脉冲电流法(by Electrical Research Association,U.K.) • Radio Influence Voltage, RIV 无线电干扰电压法 • Dielectric Loss Measurement 介质损耗法 (2) Non-Electrical Discharge Detection • Sound detection声测法 • Light detection光测法 • Temperature detection 温度测量法 • Chemical analysis 化学分析法

  14. 2. Development of PD detection techniques 2.3 Modern techniques of PD detection(research focuses) (1) PD detector (sensor) (传感器技术) • Rogowski Coil (罗氏线圈) (2) Noise Suppression Techniques (抗干扰技术) (3) PD Location Techniques (定位技术) • Acoustic Detector :Ultrasonic Detector(超声波检测器) • Advantages: strong anti-interference ability,convenient for location, online measurement.

  15. 2. Development of PD detection techniques • Light Detector : Fiber detector(光纤传感器) Light generated by PD in transformer oil has wavelength in the range from 500 nm to 700 nm. • Ultra High Frequency (UHF)Sensor(超高频传感器) PD Pulse width:10-9-10-7 s,frequency band up to 1 GHz。 Frequency range of UHF:300 MHz to 3GHz。 Advantages:to avoid noise frequency bands。 Radio frequency band < 200 MHz; Frequency band of corona < 300 MHz.

  16. 2. Development of PD detection techniques (2)Noise Suppression Techniques • Noise Suppression Circuits(噪声抑制回路,硬去噪) • Pulse Polar Discrimination Circuit 极性鉴别法 • Difference Balance Circuit 差动平衡法 • Directional Difference Balance Circuit 定向耦合差动平衡法 • Multi Adjustment Circuit多端调节法 • Digital De-noising Techniques(数字去噪技术,软去噪) • FFT-based Filters FFT阈值滤波 • FIR Filters 有限冲击响应滤波 • IIR Filters无限冲击响应滤波 • Kalman Filter 卡尔曼滤波 • Signal Correlation Analysis 信号相关分析 • Pattern Recognition模式识别 • De-noising based on Wavelet and Wavelet Package analysis 小波及小波包

  17. 2. Development of PD detection techniques (3) PD Location Techniques局部放电定位技术 • Ultrasonic Location超声波定位 • Electrical Location电气定位 • Traveling Wave Location行波法 • Capacitance Ratio Location电容比定位法 • Multi-terminal Measurement多点测量法 • Pulse Shape Identification脉冲及波形识别法 • Location with Electrical and Ultrasonic Methods声电联合定位

  18. 3. Objects and main subjects • To introduce how partial discharges influence the properties of insulation materials. To introduce how to evaluate PD behaviors and their damages to insulation materials.学习局部放电对绝缘材料性能的影响,如何评估局部放电及其对绝缘材料的影响。 • To introduce how partial discharges occur and develop in the insulation construction. To introduce the parameters that describe partial discharges;局部放电在绝缘结构中的发生与发展,学习描述局部放电的参量. • To introduce basic principles of PD detection and actual PD detection for high voltage devices.局部放电检测的基本原理以及高压电气设备的局部放电测量方法。

  19. 3. Objects and main subjects

  20. 3. Objects and main subjects

  21. Thank you!

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