CAJ | 학술논문

为了研究直流偏磁对电力变压器运行性能的影响,基于改进的变压器直流偏磁电路-磁路耦合模型,考虑铁心材料的涡流效应,定量分析了不同铁心形式和绕组联结的电力变压器产品直流偏磁下的励磁特性、漏磁特性、二次感应电动势特性和心柱直流偏置特性。通过定义变压器的直流偏置系数,统一评估了不同产品的耐受直流偏磁能力。分析结果表明,变压器直流偏置水平的升高使励磁电流波形畸变,谐波含量增加;绕组外漏磁加剧;同时二次感应电动势保持不变。三相三柱式铁心变压器受直流偏置的影响最小,而YN,yn联结单相三柱变压器组受直流偏置的影响最大。三角形联结绕组的存在对提高变压器的直流偏磁耐受能力具有积极意义。
위료연구직류편자대전력변압기운행성능적영향,기우개진적변압기직류편자전로-자로우합모형,고필철심재료적와류효응,정량분석료불동철심형식화요조련결적전력변압기산품직류편자하적려자특성、루자특성、이차감응전동세특성화심주직류편치특성。통과정의변압기적직류편치계수,통일평고료불동산품적내수직류편자능력。분석결과표명,변압기직류편치수평적승고사려자전류파형기변,해파함량증가;요조외루자가극;동시이차감응전동세보지불변。삼상삼주식철심변압기수직류편치적영향최소,이YN,yn련결단상삼주변압기조수직류편치적영향최대。삼각형련결요조적존재대제고변압기적직류편자내수능력구유적겁의의。
In order to look into the influence on the operation performance of a power transformer caused by the direct current（DC） bias,an improved electric and magnetic circuit coupled model is used.The eddy current effects of the core material are taken into consideration.The characteristics of exciting currents,leakage magnetic flux,secondary-side induced voltage,and the level of DC flux in limb are investigated for transformers with different core types and coil connections.The definition of transformer DC bias ratio is presented in the paper,with the aim of assessing the DC bias endurance in an unifed condition.The results indicate that the increasement of the DC bias ratio lead to distortion of the exciting currents waveform,increased harmonic currents and leakage magnetic flux from the coil.Meanwhile,the secondary-side induced voltage remains the same as in normal condition.In all transformer products,the three-phase three-limb transformer has the lowest level of sensitivity to the DC bias,but the single-phase three-limb tranformer bank with YN,yn connected coils has the highest level.The existence of the delta-connected coil has a positive meaning on improving the transformer endurance to the DC bias.