A Novel Insulation Monitoring Technique for Converter Transformers using Common-Mode Characteristic Harmonics of VSCs
- Resource Type
- Conference
- Authors
- Lu, Geye; Zhang, Pinjia
- Source
- 2019 IEEE 12th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED) Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED), 2019 IEEE 12th International Symposium on. :493-499 Aug, 2019
- Subject
- Aerospace
Bioengineering
Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
General Topics for Engineers
Power, Energy and Industry Applications
Signal Processing and Analysis
Transportation
Insulation
Power transformer insulation
Power conversion
Monitoring
Aging
Harmonic analysis
Common mode
Characteristic harmonics
Converter transformers
Voltage source converter
- Language
Converter transformers demand a high standard of insulation design and monitoring due to high frequency electrical stress. Traditional monitoring techniques for power transformers generally suffer from their invasive nature, and may lack sensitivity when applied to converter transformers. Effective and non-invasive insulation monitoring technique is critical for converter transformers. This paper proposes a novel online insulation monitoring technique for converter transformers, which is based on the inherent common-mode characteristic harmonics (CMCH) generated by the power switches. Two transfer functions (TF) are introduced using the measured voltages and currents at the neutral ends. Insulation ageing condition can be evaluated according to the performances of two TFs at the characteristic frequencies. Theoretical analysis, model simulation and experimental results are presented to validate the proposed technique. The importance of the proposed technique lies in its non-invasiveness and simple implementation.