计及励磁电压变化的同步发电机抛载试验参数辨识方法

传统抛载法辨识同步发电机参数时，一般假设抛载前后励磁电压保持不变，但考虑到励磁系统调节作用，这一假设在实际工程中很难满足，为此，提出了计及励磁电压变化的抛载试验参数辨识方法。将试验中实测励磁电压作为励磁绕组输入激励，求解励磁绕组及阻尼绕组的微分方程组模型，计算出励磁电流的理论值，将其与励磁电流实测值相比较，以偏差最小作为优化目标，选取发电机参数典型值为参数初值，应用蚁群算法辨识d轴参数；接着，根据d轴定子磁链求出定子电压q轴分量，并根据实测定子电压，推算出定子电压d轴分量，据此辨识q轴参数。对云南某电站水轮发电机的辨识结果验证了改进方法的有效性，与现有方法相比，改进算法具有更高的辨识精度，对试验条件限制较少，有着良好的工程应用前景。

Load Rejection Test-Based Synchronous Machine Parameters Identification Method Considering Excitation Voltage Variation

In load rejection test-based parameters identification of synchronous machine, the excitation voltage was conventionally assumed to keep constant during the test. But considering the regulation effects of the excitation control systems, it was hard to be satisfied. Therefore, an improved load rejection test-based parameters identification method for synchronous machine was proposed with considering the variation of excitation voltage. The measured excitation voltage was taken as input excitation to the field winding. The differential algebraic equations of the field and damper windings were solved. The field winding current was obtained and compared with the measured curve. Taking the minimum error as optimization objective and the classical parameters of synchronous generators as initial values, ant colony optimization was utilized to identify the parameters of d axis. Then the stator voltage in q axis was calculated through the stator flux in d axis. According to the measured stator voltage, the stator voltage in d axis was derived and used to identify the parameters of q axis. The parameters identification results of a generator in a hydraulic power plant in Yunnan power grid validated the effectiveness of the improved method. Compared with the existed method, the improved method has better accuracy and fewer restrictions about test conditions, which has a good prospect of engineering application.