The Single Phase Synchronize Generator For Power Transformer Partial Discharge Test

With the development of electric power system which is high-voltage and high-capacity, the specified voltage and the capacity of power transformer increase correspondingly. In the other hand , because partial discharge test of power transformer is done phase by phase , but at present most transformer factories use three phrases synchronous generator , only one phase of which is used , it not only make the capacity and weight of power heavier, but also influence the waveform and others performance criterion of three phrases synchronous generator single phase supply. So this paper designed a single phase synchronous generator set which includes a single phase synchronous generator, an asynchronous machine and a system of control device used in them.Compared to three-phrase synchronous generator, the difficult of single phase synchronous generator is that the magnetic field of armature reaction is pulsating. The negative sequence component is induced by pulsating magnetic field produce double frequence voltage in rotor winding of synchronous generator, which can produce positive feedback effect to the output voltage, and bring danger to the insulating tape of rotor winding. So this paper takes step as follows:1. There is a damper winding in the rotor. Because it is fixed in the outer of exciting winding and its leakage reactance is low. Then it can decline negative sequence of the magnet and reduce the influence of asymmetric operation.2. Adopting two phase winding, one is main winding (working winding), the other is secondary winding (non-working winding) .The main winding is connected in series to a pole every two windings, there are ten poles dividing into five groups, which are parallel connection. The main winding is sine and concentric, there is four coils in every group.3. Secondary winding is connected in series a group every two poles, forming a close circuit without derivation, in order to weaken the influence of induced electromotive force itself, there is a parallel electric capacity in the circuit.From the test of the prototype, it can see that this kind of method is totally feasible.