摘要
在垂直接地极冲击散流的情况下,土壤放电通道发展方向的不同对地中电磁场分布的影响不同,进而会在近区双端接地二次电缆中产生不同程度的屏蔽层感应电流和端口干扰电压。为有效预测干扰水平,该文提出一种考虑土壤放电通道方向性影响的二次电缆冲击干扰数值方法。首先,使用A-φ方程有限元法和二次电缆芯皮等效电路模型,分别计算感应电流和干扰电压的频域特性,并基于瞬时电场分布信息对土壤放电通道进行重构,通过时频域交迭计算实现了考虑放电通道影响下的干扰电压准确分析。然后,搭建采用X射线成像技术的通道观测与干扰测量试验平台,测量与仿真结果在波形上相似,最大误差为12.5%,验证了仿真模型具有一定的准确性。最后,仿真结果表明,放电通道平行于二次电缆条件下的端口电压水平可达垂直条件下的1.7倍,说明在接地系统冲击干扰研究中,极端发展方向下的土壤放电通道会引起冲击干扰强度的显著增大。因此,在接地系统电磁兼容性能的分析中有必要考虑放电通道的发展方向。
In the case of vertical grounding electrode dissipating impulse current,different development directions of the soil discharge channel have different effects on the distribution of electromagnetic field,resulting in different degrees of shield induced currents and port interference voltages in nearby two-ends grounded secondary cables.In order to effectively predict the interference level,a numerical method for impulse interference is proposed considering the channel development direction.Firstly,using the A-jequations finite element method and the equivalent circuit model of secondary cable core and sheath,the frequency domain characteristics of the induced current and the interference voltage are calculated.Based on the transient electric field distribution,the soil discharge channel is reconstructed and the accurate analysis of the interference voltage considering the influence of discharge channels is achieved through time-frequency domain alternative calculation.Next,a channel observation and interference measurement experimental platform using X-ray imaging technology is established.The measured results are similar to the simulation results in waveform,with amplitude error within 12.5%,demonstrating a certain degree of simulation accuracy.Finally,simulations reveal that when discharge channels run parallel to secondary cables,the induced port voltage reaches 1.7 times the perpendicular case.This implies that specific directions channel of the soil discharge markedly amplify impulse interference.Thus,accounting for channel orientation is necessary for grounding system EMC analysis.
作者
李小川
司马文霞
袁涛
杨鸣
李嘉伦
罗东辉
LI Xiaochuan;SIMA Wenxia;YUAN Tao;YANG Ming;LI Jialun;LUO Donghui(State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba District,Chongqing 400044,China;State Grid Sichuan Electric Power Research Institute,Chengdu 610041,Sichuan Province,China)
出处
《中国电机工程学报》
北大核心
2025年第16期6549-6560,I0034,共13页
PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING
基金
国家自然科学基金项目(51777020)
国家电网有限公司科技项目(5500-202026088A-0-0-00)。
关键词
冲击干扰
垂直接地极
土壤放电通道
电磁场
有限元法
干扰电压
impulsive interference
vertical grounding electrode
soil discharge channel
electromagnetic field
finite element method(FEM)
interference voltage
