同步发电机不对称运行工况阻尼绕组电流的计算

Calculation of Damper Winding Current for Synchronous Generators Under Asymmetric Conditions

现代水轮发电机都装设阻尼绕组,阻尼绕组电流计算的准确程度会直接影响到发电机运行性能的研究。尤其在发电机不对称运行时,阻尼绕组受负序磁场所感生的电流会对发电机的运行性能产生很大的影响。因此在研究发电机不对称运行工况时,如何准确计算阻尼绕组电流就显得尤为重要。该文利用场路耦合法计算了同步发电机在极端不对称运行工况下的阻尼绕组电流。通过建立阻尼绕组端部数学模型,考虑了端部磁场非线性对阻尼绕组电流的计算结果所带来的影响。同时也利用传统对端部磁场的处理方法计算了同步发电机不对称运行时的阻尼绕组电流。利用1台可以直接测量阻尼绕组电流实时值的试验样机对2种方法的计算结果分别进行了验证。结果表明,当发电机端部磁场饱和比较严重时,例如发电机极端不对称运行工况,该文的计算方法更适用于阻尼绕组电流的计算。

Nowadays hydro-generators are usually equipped with the damper winding. The accuracy of the calculated the damper windings currents will affect the generator＇s performance directly. Especially when generator operates in asymmetric conditions, the currents induced by the negative magnetic field will influent the generator＇s performance greatly. Therefore, to calculate the currents of the damper windings accurately gets really necessary while studying the asymmetric performance of the generator. The field-circuit coupled method is applied in the paper to calculate the damper winding currents as the generator operates in asymmetric conditions. By building the mathematical model of the damper winding＇ send, the effect from the nonlinear magnetic field at the end of the rotor is considered in the paper. Meantime the damper winding currents are also calculated through the conventional process which deal the magnetic field at the end of the damper winding with analytical method. And then, the calculated results from the both methods mentioned above are compared with the results acquired from the test, in which the instantaneous value of the damper bars currents can be measured directly. The comparison shows that the method applied in the paper is more accurate when calculating the damper winding currents when the magnetic field at the end of the rotor saturates extremely.