基金项目:
国家电网公司科技项目(5211DS16000G);
国网浙江省电力公司科技项目(5211DS150026;
5211DS150028);
Project supported by Science and Technical Program of SGCC (5211DS16000G), Science and Technical Program of Zhejiang Electric Power Corporations (5211DS150026, 5211DS150028);
In order to improve the voltage distribution in power transformer coil and enhance the insulation durability under very fast transient, the resonant features of power transformers within very fast transient frequency range are analyzed based on the improved transformer lumped model. The results show that the interleaved and improved interleaved discs at the top of the winding can reduce the maximum response factors effectively. Continuous segments are the weakest part of the winding where the most serious oscillations may possibly happen. The maximum oscillating voltage is observed at the upper half of the winding, and the position of maximum oscillation moves towards the top of the winding with the effective oscillating frequency getting higher. The research results indicate that the insulating properties near the input port should be more concerned when designing the power transformer.
KEY WORDS :power transformers;very fast transient;high-frequency attenuation;resonance analysis;partial oscillation;response factor;
图1
实测变压器绕组电压转移函数曲线及采用3种损耗因子表达式计算的曲线
Fig.1
Measured voltage transfer functions and the calculated ones by three different frequency-dependent attenuation formulas
表1
变压器线圈模型参数
Table
1 Parameters of transformer coil model
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