Off-line Insulation Testing for DFIG Rotor Winding for Wind Energy Applications = 풍력 에너지 응용분야에서 DFIG 로터 감속기 권선의 오프라인 절연 시험

다국어 초록 (Multilingual Abstract)

In recent times, there has been a significant rise in the use of inverter-operated electrical machines, especially doubly-fed inverter generators for wind energy applications
However, studies have shown that rotor insulation deterioration is one of the major caus
of failure and downtime in wind power generation. Hence, this paper introduces a nove
approach for monitoring the condition of rotor-ground insulation for doubly-fed inverte
machines. Moreover, due to the limited accessibility of these kind of power plants, i
highly desirable to implement a remote and automated insulation testing. The propose
method utilizes commonly used sensors usually employed for differential protectio
and is simple in its application. It can be implemented before/after the motor is started/stopped and can screen out severe insulation deterioration preventing machine failure
The method has been verified experimentally on a 440 V, 5.5 kW induction machine

목차 (Table of Contents)

• 1 Introduction 1
• 1.1 Background 1
• 1.1.1 Thesis Structure 4
• 1.2 Objective 5
• 2 Existing Methods for detection of winding insulation faults 6
• 2.1 Offline Methods 6
• 2.1.1 Insulation Resistance and Polarization Index 7
• 2.1.2 Surge and Surge PD test 8
• 2.1.3 DC & AC High Potential (Hipot) 9
• 2.1.4 Capacitance Test 10
• 2.1.5 Stator Capacitance TIP-UP 10
• 2.1.6 Dissipation Factor (DF) 11
• 2.1.7 Offline Partial Discharge (PD) 12
• 2.2 Limitations of Offline Methods 13
• 2.3 Online Methods 14
• 2.3.1 Temperature Monitoring 15
• 2.3.2 Ozone Monitoring 16
• 2.3.3 Online Partial Discharge 16
• 2.4 Limitations of Online Methods 17
• 3 Proposed Method 18
• 3.1 Rotor insulation model 18
• 3.2 Proposed Method 19
• 3.2.1 Leakage Current Method Advantages 23
• 4 Experimental Results 25
• 4.1 Experimental Setup 25
• 4.2 Data Processing 29
• 4.3 Results and Analysis 33
• 4.3.1 Capacitance Test 33
• 4.3.2 Resistance Test 35
• 5 Conclusion 39
• Appendix 44