基于多频率相量模型的动态同步相量测量算法

Dynamic Synchrophasor Estimator Based on Multi-frequency Phasor Model

电力系统中由于发电出力与负载不平衡导致基波频率偏移,进而造成同步相量测量精度迅速下降。基于此,该文提出基于多频率相量模型的动态同步相量测量算法。首先,算法利用多个不同旋转频率的子相量来描述真实频率附近的有效信息,并以此对动态相量进行建模;其次,通过计算粗估频率、调用离线矩阵、修正离散傅里叶变换结果及相移运算等步骤来获得精确的相量测量值。最后,仿真结果表明,算法虽然增加了有限的运算量,但在频率斜坡变化、功率振荡等动态工况中,能够减小频率偏移带来的不利影响,提供准确的测量结果。

When the power system was suffered from unbalance and fault, the fundamental frequency would deviate from the nominal frequency, and the measurement accuracy of synchrophasor estimator also would rapidly reduce. Therefore, a dynamic synchrophasor estimator was proposed based on multi-frequency phasor model. The multi-frequency phasor model was employed to reflect the effective information around real frequency, and to establish a phasor model including multi-frequency phasor. The accuracy phasor value could be obtained by estimating rough frequency, looking the matrix table calculated offline, revising the discrete Fourier transform（DFT） value and shifting phasor. Test results of both simulated signals and PSCAD/EMTDC generated signal show that the proposed estimator can provide accurate phasor estimations under dynamic conditions of frequency ramping and power oscillation at the cost of limited increase of computational burden.