在分析小电流接地系统中传统小波包选线方法的优势与不足的基础上,提出一种基于多孔算法小波包变换的多频带分量重构自适应选线新方法:首先根据系统运行方式和线路参数确定出选择频带(selected frequency band,SFB)的范围,然后利用多孔...在分析小电流接地系统中传统小波包选线方法的优势与不足的基础上,提出一种基于多孔算法小波包变换的多频带分量重构自适应选线新方法:首先根据系统运行方式和线路参数确定出选择频带(selected frequency band,SFB)的范围,然后利用多孔算法小波包变换良好的分频特性与保持线性相位的性质,对故障零序电流采样数据进行多尺度分解,自适应地选择落在SFB范围内的多频带分量进行重构,极大限度地提取了有效的故障零序电流分量信息,并构造出能综合利用小波包重构系数幅值与极性信息的选线算法,进一步提高了选线灵敏度。理论分析和大量的PSCAD仿真表明,该方法有效地提高了故障选线的准确性,其灵敏度高,自适应能力强,同时适用于中性点不接地系统和中性点经消弧线圈接地系统。展开更多
A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. B...A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.展开更多
文摘在分析小电流接地系统中传统小波包选线方法的优势与不足的基础上,提出一种基于多孔算法小波包变换的多频带分量重构自适应选线新方法:首先根据系统运行方式和线路参数确定出选择频带(selected frequency band,SFB)的范围,然后利用多孔算法小波包变换良好的分频特性与保持线性相位的性质,对故障零序电流采样数据进行多尺度分解,自适应地选择落在SFB范围内的多频带分量进行重构,极大限度地提取了有效的故障零序电流分量信息,并构造出能综合利用小波包重构系数幅值与极性信息的选线算法,进一步提高了选线灵敏度。理论分析和大量的PSCAD仿真表明,该方法有效地提高了故障选线的准确性,其灵敏度高,自适应能力强,同时适用于中性点不接地系统和中性点经消弧线圈接地系统。
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB719802), and the Science and Technology De-partment of Zhejiang Province (No. 2005C31004), China
文摘A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.
