摘要
高空电磁脉冲晚期成分(HEMP E3)效应会在变压器中性点与大地构成的回路中产生地磁感应电流(GIC),严重时会使变压器铁心半波饱和,进而导致励磁电流严重畸变、无功损耗急剧增加、局部过热和振动加剧等后果。为准确地分析电力变压器在HEMPE3作用下的无功损耗特性,该文搭建了HEMP E3对500 kV电力变压器作用的电磁暂态仿真模型,基于IEC 61000-2-9给出的标准HEMP E3波形,定量分析了感应电场幅值、上升时间、下降时间以及变压器带负载情况等对电力变压器的影响规律。分析结果表明,HEMP E3作用下500 kV变压器无功损耗与GIC呈正相关性,且无功损耗波形滞后于感应电场的变化;HEMP E3感应电场的下降时间对500 kV变压器无功损耗的影响远超上升时间;负载阻抗的阻值相同时,容性负载下的励磁电流和无功损耗幅值最大,感性负载下幅值最小。研究结果可为进一步评估HEMPE3对电力系统稳定性的影响提供重要依据。
The effect of late-time high-altitude electromagnetic pulses(HEMP E3)can generate geomagnetic induced currents in the circuit between the earth and neutral points of transformers.In serious cases,it may make the transformer core half-cycle saturated,resulting in serious consequences,like distortion of excitation current,increase of reactive power loss,hot-spot heating and vibration.However,the existing literature usually adopted the results under steady-state direct current for E3 impact assessment,and the dynamic characteristics of transformer under E3 waveform were not fully considered.In order to analyze the influence of E3 characteristics,such as high magnitude and short duration,this paper builds an electromagnetic transient model of a 500 kV transformer.Based on IEC 61000-2-9 standard,this paper quantitatively analyzes the resulting variation of excitation current and reactive power loss of the Wye-Delta-connection transformer under HEMP E3,considering the amplitude,rising time,falling time of the induced geoelectric field,as well as transformer load type and other factors.The actual HEMP E3 induced electric fields are affected by the non-uniform earth conductivity and coast effect,and the waveform may change considerably.Thus,this paper calculates the E3 induced electric field under the uniform earth model and the 1D layered conductivity model.The results show that for the realistic earth conductivity models,the induced geoelectric fields change not only in amplitude but also in waveform.Therefore,this paper studies the influence of peak value,rise time and fall time of E3 induced electric field on reactive power loss of 500 kV transformer.To analyze the influence of the electric field amplitude,this paper selects 0.5 times,1 time,2 times,5 times and 10 times of the IEC standard waveform,which are imposed on the 100 km transmission line respectively.The results show that as the amplitude of E3 electric field increases,the reactive power loss will be larger.It is worth noticing that there exists an upper li
作者
杨一帆
刘民周
谢彦召
陈宇浩
田爽
Yang Yifan;Liu Minzhou;Xie Yanzhao;Chen Yuhao;Tian Shuang(State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China;Xi'an Thermal Power Research Institute Co.Ltd,Xi'an 710054,China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第1期267-277,共11页
Transactions of China Electrotechnical Society
基金
华能集团总部科技项目(HNKJ21-H49)
国家留学基金委奖学金(202006280077)
中国科协优秀中外青年交流计划资助。
关键词
变压器
地磁感应电流
高空电磁脉冲晚期成分
无功损耗
Transformer
geomagnetically induced current
late-time high-altitude electromagnetic pulses
reactive power loss
