Transformer winding deformation tester in what field test conditions can be operated?

Transformer winding deformation tester is a special instrument for transformer winding test.

Transformer winding deformation test is a test method widely used in power system to detect whether it is deformed in recent years. It can effectively find the axial and radial dimension change of transformer, body displacement, winding distortion, bulging and inter-turn short circuit. Energized conductors are subjected to electrodynamic forces in a magnetic field. A phase winding of a transformer is also in the magnetic field formed by the other two phases and can also be subjected to electrodynamic forces. When the winding passes a normal load current, the electromotive force Very small, it will not pose a hazard to the windings, but when a short circuit accident occurs, especially when the short circuit point is very close to the secondary exit of the transformer, the short-circuit current will be very large, and the powerful motor will cause the transformer winding to vibrate violently and even deform.

Because the transformer is a fully enclosed electrical device, it is difficult to see the internal deformation of the appearance, and people have come up with a way to understand the winding deformation through an external test, this method is called "the frequency response characteristics of the winding test ". The basic principle of the winding deformation test is to regard the transformer winding as an inductance coil. Any change in the shape of the winding will cause a change in the inductance, which will result in a change in the frequency curve.

It is to add a given frequency on one side of the transformer and receive the frequency on the other side. Check the received frequency curve and frequency curve, and whether there is a big difference in the frequency curve recorded at the time of delivery or new investment. If the difference is small, it means that there is no deformation of the winding. If there is a big difference between the two, it means that the winding may have large deformation, and the overhaul of the core (shroud) should be carried out.

Transformer winding deformation test should meet the following requirements:

1. For 35kV and below voltage grade transformers, low voltage short circuit impedance method should be adopted;

2. For transformers with a voltage rating of 66kV and above, it is recommended to use the frequency response measurement winding characteristic map.

3, the transformer grounding condition is good, the casing lead should be fully unlocked.

When we use the transformer winding deformation tester to conduct field tests, we must follow the above conditions, which is very helpful for us to complete the test.