The advance in the wide-area measurement system (WAMS) is driving the power system to the trend of wide-area monitoring and control.The Prony method is usually used for low frequency oscillation online identification....The advance in the wide-area measurement system (WAMS) is driving the power system to the trend of wide-area monitoring and control.The Prony method is usually used for low frequency oscillation online identification.However,the identified amplitude and phase information is not sufficiently used.In this paper,the amplitude is adopted to detect the occurrence of the oscillation and to obtain the mode observability of the sites.The phase is adopted to identify the oscillation generator grouping and to obtain the mode shapes.The time varying characteristics of low frequency oscillations are studied.The behaviors and the characters of low frequency oscillations are displayed by dynamic visual techniques.Demonstrations on the "11.9" low frequency oscillation of the Guizhou Power Grid substantiate the feasibility and the validation of the proposed methods.展开更多
A novel single-ended online fault location algorithm is investigated for DC distribution networks. The proposed algorithm calculates the fault distance based on the characteristics of the voltage resonance. The Prony&...A novel single-ended online fault location algorithm is investigated for DC distribution networks. The proposed algorithm calculates the fault distance based on the characteristics of the voltage resonance. The Prony's method is introduced to extract the characteristics. A novel method is proposed to solve the pseudo dual-root problem in the calculation process. The multiple data windows are adopted to enhance the robustness of the proposed algorithm. An index is proposed to evaluate the accuracy and validity of the results derived from the various data windows. The performances of the proposed algorithm in different fault scenarios were evaluated using the PSCAD/EMTDC simulations. The results show that the algorithm can locate the faults with transient resistance using the 1.6 ms data of the DC-side voltage after a fault inception and offers a good precision.展开更多
准确辨识低频振荡波形的主导模式参数对于有效抑制低频振荡,保障系统安全稳定运行具有重要意义。从抗噪声干扰性能、辨识频率相近主导振荡模式的分辨率以及动态特性三个指标对常用于低频振荡波形分析的基于总体最小二乘法-旋转不变技术...准确辨识低频振荡波形的主导模式参数对于有效抑制低频振荡,保障系统安全稳定运行具有重要意义。从抗噪声干扰性能、辨识频率相近主导振荡模式的分辨率以及动态特性三个指标对常用于低频振荡波形分析的基于总体最小二乘法-旋转不变技术参数估计法(Total Least Squares-Estimation of Signal Parametersvia Rotational Invariance Techniques,TLS-ESPRIT)和Prony方法进行比较分析。MATLAB仿真结果表明,TLS-ESPRIT方法和Prony方法均具有较高的频率分辨率,TLS-ESPRIT的抗噪声干扰能力以及动态特性优于Prony方法。展开更多
提出了基于局部均值分解(LMD)的同步电机参数辨识方法。采用LMD从短路电流中提取直流电流和基波电流,然后分别采用稳健回归最小二乘和Prony算法对直流电流和基波电流进行辨识,进而获得同步电机参数。以理想突然短路电流信号为例,通过仿...提出了基于局部均值分解(LMD)的同步电机参数辨识方法。采用LMD从短路电流中提取直流电流和基波电流,然后分别采用稳健回归最小二乘和Prony算法对直流电流和基波电流进行辨识,进而获得同步电机参数。以理想突然短路电流信号为例,通过仿真分析了滑动平均跨度与LMD循环次数和电流相对均方误差的关系,确定了滑动平均跨度。高信噪比(30 d B)时,由于LMD具有平滑滤波功能而无模态混叠现象发生。低信噪比(15 d B)时,提出了基于前置滑动平均LMD的短路电流分离方法,可有效获取直流电流和基波电流分量。较之经验模态分解(EMD),基于LMD的理想突然短路电流分解效果更好。仿真结果表明,与EMD方法相比,所提方法受噪声影响较小,参数辨识精度更高。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50595413)
文摘The advance in the wide-area measurement system (WAMS) is driving the power system to the trend of wide-area monitoring and control.The Prony method is usually used for low frequency oscillation online identification.However,the identified amplitude and phase information is not sufficiently used.In this paper,the amplitude is adopted to detect the occurrence of the oscillation and to obtain the mode observability of the sites.The phase is adopted to identify the oscillation generator grouping and to obtain the mode shapes.The time varying characteristics of low frequency oscillations are studied.The behaviors and the characters of low frequency oscillations are displayed by dynamic visual techniques.Demonstrations on the "11.9" low frequency oscillation of the Guizhou Power Grid substantiate the feasibility and the validation of the proposed methods.
基金supported by the National Basic Research Program of China("973" Project)(Grant No.2012CB215206)the National Natural Science Foundation of China(Grant Nos.51407067&51222703)the "111" Project of China(Grant No.B08013)
文摘A novel single-ended online fault location algorithm is investigated for DC distribution networks. The proposed algorithm calculates the fault distance based on the characteristics of the voltage resonance. The Prony's method is introduced to extract the characteristics. A novel method is proposed to solve the pseudo dual-root problem in the calculation process. The multiple data windows are adopted to enhance the robustness of the proposed algorithm. An index is proposed to evaluate the accuracy and validity of the results derived from the various data windows. The performances of the proposed algorithm in different fault scenarios were evaluated using the PSCAD/EMTDC simulations. The results show that the algorithm can locate the faults with transient resistance using the 1.6 ms data of the DC-side voltage after a fault inception and offers a good precision.
文摘准确辨识低频振荡波形的主导模式参数对于有效抑制低频振荡,保障系统安全稳定运行具有重要意义。从抗噪声干扰性能、辨识频率相近主导振荡模式的分辨率以及动态特性三个指标对常用于低频振荡波形分析的基于总体最小二乘法-旋转不变技术参数估计法(Total Least Squares-Estimation of Signal Parametersvia Rotational Invariance Techniques,TLS-ESPRIT)和Prony方法进行比较分析。MATLAB仿真结果表明,TLS-ESPRIT方法和Prony方法均具有较高的频率分辨率,TLS-ESPRIT的抗噪声干扰能力以及动态特性优于Prony方法。
文摘提出了基于局部均值分解(LMD)的同步电机参数辨识方法。采用LMD从短路电流中提取直流电流和基波电流,然后分别采用稳健回归最小二乘和Prony算法对直流电流和基波电流进行辨识,进而获得同步电机参数。以理想突然短路电流信号为例,通过仿真分析了滑动平均跨度与LMD循环次数和电流相对均方误差的关系,确定了滑动平均跨度。高信噪比(30 d B)时,由于LMD具有平滑滤波功能而无模态混叠现象发生。低信噪比(15 d B)时,提出了基于前置滑动平均LMD的短路电流分离方法,可有效获取直流电流和基波电流分量。较之经验模态分解(EMD),基于LMD的理想突然短路电流分解效果更好。仿真结果表明,与EMD方法相比,所提方法受噪声影响较小,参数辨识精度更高。
