考虑衰减直流分量的动态相量强跟踪测量算法

故障电流信号的频率变化以及包含的衰减直流分量会严重影响基于傅里叶变换的相量测量算法的精度和动态响应速度。文中提出了一种利用强跟踪滤波器滤除衰减直流分量的动态相量测量算法。首先,将衰减直流分量用其二阶泰勒展开多项式来表示,在状态变量中添加衰减直流分量及其一阶导数和二阶导数,建立含有基波角频率、幅值等参数和衰减直流分量参数的故障电流的非线性状态空间模型,减小信号估计的模型误差。其次,为了提高扩展卡尔曼滤波器在系统达到稳定时对系统参数突变的跟踪能力,利用强跟踪滤波器递推估计各状态变量。所提方法能够有效抑制衰减直流分量对相量测量精度的影响,对时变故障电流信号具有良好的动态响应能力。采用所提算法对加噪声的数值信号以及ATP-EMTP故障仿真信号进行相量测量,结果验证了算法的正确性与有效性。

Strong Tracking Filter Algorithm for Dynamic Phasor Measurement Considering Decaying DC Component

The frequency change of the fault current signal and the decaying DC component contained in the signal will seriously decrease the accuracy and dynamic response speed of the phasor measurement algorithm based on Fourier transform algorithm. This paper proposes a strong tracking filter algorithm for dynamic phasor measurement considering the decaying DC component. Firstly, the decaying DC component is expressed by its second-order Taylor polynomial, and the decaying DC component and its first and second derivative are all added to the state variable vector. Then this paper establishes a nonlinear state space model of fault current including angular frequency and amplitude of the fundamental component and the decaying DC component, to reduce the estimation model error. In order to improve the ability of extended Kalman filter to fast track the system parameter mutation when the system reaches a steady state, the strong tracking filter is used to recursively estimate each state variable. The proposed method can effectively decrease the impacts of the decaying DC component on phasor estimation and has good dynamic response to time-varying fault current signals. Finally, the proposed algorithm is used to measure the numerical signal with noise and the fault simulation signal generated by ATP-EMTP. The test results verify the correctness and validity of the proposed algorithm.