基于CML的配电网μPMU相量测量算法
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摘要
配电网受谐波和噪声干扰严重,电压相量的计算难度更大,传统的输电网相量测量精度不能满足配电网的要求。为提高配电网电压相量幅值和相角的测量精度,提出了一种基于条件最大似然估计法(conditional maximum likelihood estimation,CML)的配电网微型同步相量测量单元(μPMU)的相量测量方法。该算法建立了三相不平衡系统的信号模型,在待测量最多包含两个未知量且待测量矩阵与单位矩阵正交不等于零时,利用三相矩阵与样本协方差矩阵的特征向量正交来获取待测量,进而通过几何特性推导出电压相量的幅值及相位表达式,降低了运算量。通过Matlab进行了仿真验证,仿真结果表明所提方法能够在一定程度上提高配电网电压相量幅值和相位的测量精度。
Distribution network is seriously affected by harmonics and noise,the calculation of voltage phasor is more difficult,and the traditional phasor measurement accuracy of power transmission network can not satisfy the demand of distribution network.In order to improve the measurement accuracy of voltage amplitude and phase angle of distribution network,a method based on conditional maximum likelihood estimation (CML) is proposed for measuring the phasor of micro-synchronous phasor measurement unit (μPMU)in distribution network.The algorithm establishes the signal model of three-phase unbalanced system.When the measurement is up to two unknowns and the orthogonal value of the measured matrix and the unit matrix is not equal to zero,the feature which the threephase matrix is orthogonal to the eigenvector of the sample covariance matrix is used to obtain the measurement.Furthermore,the amplitude and phase expression of the voltage phasor are deduced by the geometric characteristic,which reduces the computational complexity.Simulation test is carried out by Matlab,and the simulation results showthat the proposed method can improve the measurement accuracy of the voltage amplitude and phase angle of distribution network to a certain extent.
Distribution network is seriously affected by harmonics and noise,the calculation of voltage phasor is more difficult,and the traditional phasor measurement accuracy of power transmission network can not satisfy the demand of distribution network.In order to improve the measurement accuracy of voltage amplitude and phase angle of distribution network,a method based on conditional maximum likelihood estimation (CML) is proposed for measuring the phasor of micro-synchronous phasor measurement unit (μPMU)in distribution network.The algorithm establishes the signal model of three-phase unbalanced system.When the measurement is up to two unknowns and the orthogonal value of the measured matrix and the unit matrix is not equal to zero,the feature which the threephase matrix is orthogonal to the eigenvector of the sample covariance matrix is used to obtain the measurement.Furthermore,the amplitude and phase expression of the voltage phasor are deduced by the geometric characteristic,which reduces the computational complexity.Simulation test is carried out by Matlab,and the simulation results showthat the proposed method can improve the measurement accuracy of the voltage amplitude and phase angle of distribution network to a certain extent.
引文
[1]杨帆.主动配电网的适用可行技术探讨—访中国电力科学研究院教授级高工张祖平[J].电气应用,2016,35(13):4-6.YANG Fan.Discussion on applicable and available technology of active distribution network—interviewwith Zhang Zuping,a professor at the China Electric Power Research Institute[J].Electrical Applications,2016,35(13):4-6.
[2]何正友.分布式新能源接入电网的谐波热点问题探讨[J].南方电网技术,2016,10(3):47-52.HE Zhengyou.Discussion on harmonic hot issues of distributed newenergy connected to power grid[J].Southern Power System Technology,2016,10(3):47-52.
[3]王宾,孙华东,张道农.配电网信息共享与同步相量测量应用技术评述[J].中国电机工程学报,2015,35(S1):1-7.WANG Bin,SUN Huadong,ZHANG Daonong.Distribution network information sharing and synchronous phasor measurement technology[J].Proceedings of the CSEE,2015,35(S1):1-7.
[4]李江,徐志临,李国庆,等.配电网微型PMU与故障录波装置研究与开发[J].电力自动化设备,2016,35(9):54-59.LI Jiang,XU Zhilin,LI Guoqing,et al.Research and development ofμPMU and fault wave recording device for distribution network[J].Electric Power Automation Equipment,2016,35(9):54-59.
[5]文安,黄维芳.基于广域信息的区域控制保护技术[J].南方电网技术,2016,10(5):16-21.WEN An,HUANG Weifang.Regional control and protection technology based on wide area information[J].Southern Power Grid Technology,2016,10(5):16-21.
[6]刘林,林涛,曹健,等.基于时频原子变换的电力系统同步相量测量算法[J].电力系统自动化,2011,35(3):39-43.LIU Lin,LIN Tao,CAO Jian,et al.A power system synchronized phasor measurement algorithm based on time-frequency transform[J].Automation of Electric Power Systems,2011,35(3):39-43.
[7]符玲,韩文朕,麦瑞坤,等.基于时域信息的动态同步相量测量算法[J].中国电机工程学报,2015,35(23):6075-6082.FU Ling,HAN Wenzhen,MAI Ruikun,et al.Time-frequency information-based dynamic phasor estimator[J].Proceedings of the CSEE,2015,35(23):6075-6082.
[8]符玲,韩文朕,麦瑞坤,等.基于频域动态模型的同步相量测量算法[J].中国电机工程学报,2015,35(6):1371-1378.FU Ling,HAN Wenzhen,MAI Ruikun,et al.Dynamic phasor estimator based on frequency-domain model[J].Proceedings of the CSEE,2015,35(6):1371-1378.
[9]刘世明,郭韬,吴聚昆,等.适用于频率偏移情况下同步相量测量的DFT算法研究[J].电网技术,2016,40(5):1522-1528.LIU Shiming,GUO Tao,WU Jukun,et al.Research on DFT algorithm for synchronous phasor measurement in frequency offset[J].Power System Technology,2016,40(5):1522-1528.
[10]张姝,何正友,何文.基于递归小波的相量测量算法[J].电网技术,2011,35(4):194-200.ZHANG Shu,HE Zhengyou,HE Wen.Phasor measurement algorithm based on recursive wavelet[J].Power System Technology,2011,35(4):194-200.
[11]CASTELLO P,LIXIA M,MUSCAS C,et al.Impact of the model on the accuracy of synchrophasor measurement[J].IEEE Transactions on Instrumentation&Measurement,2012,61(8):2179-2188.
[12]IEEE standard for synchrophasor measurements for power systems:IEEE Std C37.118.1-2011.2011[J].NewYork:IEEE,2011.
[13]PETRE S,NEHORAI A.Music,maximum likelihood,and cramer-rao bound[J].IEEE Transactions on Acoustics,Speech and Signal Processing,1989,24(3):720-741.
[14]V Choqueuse,A Belouchrani,E-H El Bouchikhi,et al.Estimation of amplitude,phase and unbalance parameters in three-phase systems:Analytical solutions,effcient implementation and performance analysis.IEEE Transactions on Signal Processing,2014,62(16):4064-4076.
[15]RENAUX A,FORSTER P,CHAUMETTE E.On the highSNR conditional maximum-likelihood estimator full statistical characterization[J].IEEE Transactions on Signal Processing.2006,54(12):4840-4843.
[16]GUYEN N C T,SNNIVASAN K.A newtechnique for rapid tracking of frequency deviations based on level crossings[J].IEEE Transactions on Power Apparatus and Systems,1984,103(8):2230-2236.
[17]束洪春.电力工程信号处理应用[M].北京:科学出版社,2009.
[18]胡健,陈文宪,陈冬冬,等.基于中线电流注入的三电平有源电力滤波器中点平衡策略[J].电网技术,2014,38(11):3160-3165.HU Jian,CHEN Wenxian,CHEN Dongdong,et al.Neutral balance strategy of three-level active power filter based on midline current injection[J].Power System Technology,2014,38(11):3160-3165.
[19]KAY S.Fundamentals of statistical signal processing:estimation theory[M].NJ,USA:Prentice-Hall,1993.
[2]何正友.分布式新能源接入电网的谐波热点问题探讨[J].南方电网技术,2016,10(3):47-52.HE Zhengyou.Discussion on harmonic hot issues of distributed newenergy connected to power grid[J].Southern Power System Technology,2016,10(3):47-52.
[3]王宾,孙华东,张道农.配电网信息共享与同步相量测量应用技术评述[J].中国电机工程学报,2015,35(S1):1-7.WANG Bin,SUN Huadong,ZHANG Daonong.Distribution network information sharing and synchronous phasor measurement technology[J].Proceedings of the CSEE,2015,35(S1):1-7.
[4]李江,徐志临,李国庆,等.配电网微型PMU与故障录波装置研究与开发[J].电力自动化设备,2016,35(9):54-59.LI Jiang,XU Zhilin,LI Guoqing,et al.Research and development ofμPMU and fault wave recording device for distribution network[J].Electric Power Automation Equipment,2016,35(9):54-59.
[5]文安,黄维芳.基于广域信息的区域控制保护技术[J].南方电网技术,2016,10(5):16-21.WEN An,HUANG Weifang.Regional control and protection technology based on wide area information[J].Southern Power Grid Technology,2016,10(5):16-21.
[6]刘林,林涛,曹健,等.基于时频原子变换的电力系统同步相量测量算法[J].电力系统自动化,2011,35(3):39-43.LIU Lin,LIN Tao,CAO Jian,et al.A power system synchronized phasor measurement algorithm based on time-frequency transform[J].Automation of Electric Power Systems,2011,35(3):39-43.
[7]符玲,韩文朕,麦瑞坤,等.基于时域信息的动态同步相量测量算法[J].中国电机工程学报,2015,35(23):6075-6082.FU Ling,HAN Wenzhen,MAI Ruikun,et al.Time-frequency information-based dynamic phasor estimator[J].Proceedings of the CSEE,2015,35(23):6075-6082.
[8]符玲,韩文朕,麦瑞坤,等.基于频域动态模型的同步相量测量算法[J].中国电机工程学报,2015,35(6):1371-1378.FU Ling,HAN Wenzhen,MAI Ruikun,et al.Dynamic phasor estimator based on frequency-domain model[J].Proceedings of the CSEE,2015,35(6):1371-1378.
[9]刘世明,郭韬,吴聚昆,等.适用于频率偏移情况下同步相量测量的DFT算法研究[J].电网技术,2016,40(5):1522-1528.LIU Shiming,GUO Tao,WU Jukun,et al.Research on DFT algorithm for synchronous phasor measurement in frequency offset[J].Power System Technology,2016,40(5):1522-1528.
[10]张姝,何正友,何文.基于递归小波的相量测量算法[J].电网技术,2011,35(4):194-200.ZHANG Shu,HE Zhengyou,HE Wen.Phasor measurement algorithm based on recursive wavelet[J].Power System Technology,2011,35(4):194-200.
[11]CASTELLO P,LIXIA M,MUSCAS C,et al.Impact of the model on the accuracy of synchrophasor measurement[J].IEEE Transactions on Instrumentation&Measurement,2012,61(8):2179-2188.
[12]IEEE standard for synchrophasor measurements for power systems:IEEE Std C37.118.1-2011.2011[J].NewYork:IEEE,2011.
[13]PETRE S,NEHORAI A.Music,maximum likelihood,and cramer-rao bound[J].IEEE Transactions on Acoustics,Speech and Signal Processing,1989,24(3):720-741.
[14]V Choqueuse,A Belouchrani,E-H El Bouchikhi,et al.Estimation of amplitude,phase and unbalance parameters in three-phase systems:Analytical solutions,effcient implementation and performance analysis.IEEE Transactions on Signal Processing,2014,62(16):4064-4076.
[15]RENAUX A,FORSTER P,CHAUMETTE E.On the highSNR conditional maximum-likelihood estimator full statistical characterization[J].IEEE Transactions on Signal Processing.2006,54(12):4840-4843.
[16]GUYEN N C T,SNNIVASAN K.A newtechnique for rapid tracking of frequency deviations based on level crossings[J].IEEE Transactions on Power Apparatus and Systems,1984,103(8):2230-2236.
[17]束洪春.电力工程信号处理应用[M].北京:科学出版社,2009.
[18]胡健,陈文宪,陈冬冬,等.基于中线电流注入的三电平有源电力滤波器中点平衡策略[J].电网技术,2014,38(11):3160-3165.HU Jian,CHEN Wenxian,CHEN Dongdong,et al.Neutral balance strategy of three-level active power filter based on midline current injection[J].Power System Technology,2014,38(11):3160-3165.
[19]KAY S.Fundamentals of statistical signal processing:estimation theory[M].NJ,USA:Prentice-Hall,1993.