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Dissolved gas analysis (DGA) is the most effective method to detect incipient faults in power transformers. It uses the concentrations of various gases dissolved in the transformer oil due to decomposition of the oil and paper insulation. Gases such as hydrogen, methane, acetylene, ethylene, and ethane are generated as a results of oil decomposition, while carbon monoxide and carbon dioxide are generated...
Spectroscopy is a powerful non-destructive technique that utilizes electromagnetic radiation interaction effect to determine the energy level and structure of atomic or molecular substance. Spectroscopy technique has been successfully used to quantify some power transformer condition monitoring parameters such as Furan and oil interfacial tension value. This paper investigates the feasibility of extending...
High-frequency harmonics occur in converter transformers, which may lead to unexpected breakdown of oil impregnated paper insulation under ac-dc combined voltages with high frequencies. Here in this paper, the breakdown characteristics of oil impregnated paper insulation under ac-dc combined voltages in frequencies of 50∼600 Hz were experimentally investigated. After considering the characteristics...
Electric conduction of oil impregnated paper under different temperatures and different DC electric fields has significant influences on the insulation structure design of converter transformer. This paper focuses on the influence of temperature and DC Electric Field on the electric Conduction of oil impregnated paper insulation, as well as conduction mechanism of oil impregnated paper through the...
As the core equipment of the DC transmission system, the converter transformers have been widely used in power systems. The space charge accumulation, transport and dissipation in oil-paper insulation are more complex than in polymeric insulating materials. Insulation damage caused by space charge is one of the main reasons for transformer fault, and has become a direct threat to the safe operation...
Space charge behavior is important in the oil-immersed-paper insulation in converter transformers for HVDC transmission. This paper reports an investigation of the space charge property in samples with two layers of oil-immersed-paper and oil. Based on pulsed electroacoustic (PEA) technique, a waveform recovery method was proposed to get rid of the effects of interface and anisotropy on PEA result,...
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