一台100MVA、60Hz的三相同步发电机,由具有常值同步速度的原动机驱动,电机的电抗标值和时间常数如下 X" d =0.20p.u.,τ" d =0.04s X'=0.30p.u.,τ' d =1.0s X d =1.20p.u.,τ a =0.25s 电枢绕组初始时开路,调整励磁电压,使电枢机端电压为额定值(标值为1p.u.)。在转子交轴与a相磁轴重合即δ=π/2时,同步电机发生三相对称短路故障,试画出a相电枢电流的不对称波形。并求:
【简答题】Read the following sentences from the text and choose the proper rhetorical device from those given below. You may use it more than once. ( )J.L.B.Smith 5 , the man who described the species, wrote in...