计及磁饱和的同步发电机内电势幅值测量方法

在直接测量转子位置获取同步发电机内电势相位的基础上,给出了同步发电机内电势幅值的准确直接计算方法,该方法的准确性只依赖于机端电压、机端电流、发电机功角等电气测量结果的准确性,与同步发电机参数无关。同时,基于内电势幅值和相位的准确测量,给出了能够计及磁路饱和影响的同步发电机定子与转子间互感电抗和同步电抗的计算方法,并基于正态分布参数估计理论,给出电抗计算结果的置信区间和点估计值,实际算例表明,所述方法准确可靠。

An Internal Voltage Measuring Method for Generators Taking Saturation into Account

The angle of a synchronous generator's internal voltage can be directly calibrated against the rotor position acquired by the phasor measurement unit(PMU). However, presently, there is no direct method to calculate the amplitude of internal voltage. Based on accurate measurement of the internal voltage angle, this paper proposes a direct method to calculate internal voltage amplitude. The proposed method has nothing to do with the generator's parameters, its accuracy depends only on the measuring accuracy of the electrical measurements(including terminal voltage, terminal current and power angle). Furthermore, a method of calculating x_d(d-axis synchronous reactance)and x_df(mutual reactance between field winding and stator winding)is proposed, which is capable of taking into account the influence of magnetic saturation. Based on the statistical theory of normal distribution, a robust parameter identification algorithm is proposed to give the confidence interval and point estimation of x_d and x_df. Examples based on the wide area measurement system(WAMS)at North China power grid show that the proposed method is feasible and reliable.