A Synchronous Machine with Abnormal Damper Winding Parameters

Resumo

Abstract—During the operation of synchronous explicit-pole machines, the damper winding failures can occur due to electromechanical and thermal effects on the elements upon a sudden short circuit of a stator winding, at frequent launches in the motoring mode, and at three-phase voltage unbalance. These effects can lead to damage to the contacts of rods of the damper winding with its short-circuiting rings and to the destruction of elements of the rings themselves. The defects can appear in a noticeable form only in the transient, asynchronous, and asymmetric modes. Based on a 2D analytical model of a synchronous explicit-pole machine in d, q coordinates, the rod currents and electromagnetic torque are analyzed in the asynchronous machine mode upon breakage of rods and interpole bridges near one or two poles of a damper winding. It has been concluded that the most dangerous anomaly of a damper winding is the breakage of interpole bridges near one or two poles, upon which high currents occur in rods and the electromagnetic torque is ten times higher than the nominal value.