基于相量测量单元实测数据的变压器参数在线估计方法

Online Estimation of Transformer Parameters Based on PMU Measurements

给出了基于相量测量单元(PMU)实测数据的变压器变比(分接头位置)和电抗参数的计算方法。通过对变压器参数和变比的多时段计算结果进行统计分析发现,多时段参数计算结果符合正态分布。利用正态分布参数估计理论,给出了变压器参数和变比辨识结果的置信区间和点估计值,最大限度地减少了量测随机误差的影响。算法考虑了电力系统的生产实际情况,在三绕组变压器低压侧无量测的情况下,能够准确给出变压器分接头实际位置的计算结果。算例表明,该方法准确可靠,能够应用于实践。

Based on phasor measurement unit （PMU） measurements, an online algorithm is presented to calculate power transformer＇ s winding reactances and transformation ratio. It is found that due to the random error of PMU measurements, the multi-period parameter calculation results comply with a normal distribution. Furthermore, based on the statistics theory of normal distribution, a robust parameter identification algorithm is proposed to give confidence interval and point estimation of transformer＇s parameters and transformation ratio. Considering that low voltage side of three-winding transformer is usually connected with reactive power compensation devices, the algorithm can precisely identify the tap changer positiong without low voltage side PMU measurements. ,Examples from a wide area measurement system （WAMS） in North China power grid show that the methods proposed is feasible and reliable.