Method for repairing anti-corona layer of generator stator bar

Abstract

The invention discloses a method for repairing an anti-corona layer of a generator stator bar. In order to prevent corona and corrosion of a bar insulating material at the end part, a ventilation notch and other parts of a generator stator bar, anti-corona treatment needs to be carried out on the slot part and the end part of the stator bar, and along with the increase of the operation age limit,anti-corona layers on the surfaces of part of the bars gradually fall off and are damaged to endanger the safe operation of a unit. In order to solve the problem, the invention provides the method forrepairing the anti-corona layer of the generator stator bar, the damaged anti-corona layer can be repaired on site, and the long-term safe and stable operation of a unit is ensured.

Description

technical field [0001] The invention relates to the technical field of generator insulation, in particular to a method for repairing an anti-corona layer of a stator bar of a generator. Background technique [0002] In the prior art, the stator winding of the generator is a core component of the generator, and the insulation state of the stator winding is a key factor determining the service life and operation reliability of the generator. With the improvement of the capacity and voltage level of high-voltage electrical equipment, the part of the insulation with a small radius of curvature will generate corona under the action of a local strong field, which has become a common fault in the insulation of generators. In order to improve this situation, it is necessary to carry out anti-corona treatment on the slot and end of the stator bar. The purpose is to make the electric field distribution at the end of the bar uniform, so that the stator bar does not produce corona durin...

AI Technical Summary

Problems solved by technology

[0004] On the one hand, the stator bar has been soaked in oil for a long time, so that the insulating paint on the surface of the bar exiting the notch dissolves and falls off, and then further damages the anti-corona layer, while the electric field at the part of the bar exiting the notch is relatively concentrated, resulting in corona

The corona ionizes the oxygen in the air to generate ozone, and the generated ozone combines with nitrogen to form nitrate, which corrodes the wire rod. In this way, the contact resistance on the surface of the wire rod will become larger and larger, so that the corona area will continue to expand and generate electricity. Corrosion, which in turn damages the main insulation of the wire rod, resulting in a breakdown accident of the wire rod. In the process of on-site assembly and welding, there are welding lumps and welding slag left in the rotor, and some small particles of impurities may remain in the rotor during the rotor assembly process.

During the operation of the unit, the loose welding lumps on the rotor and the remaining small particles of welding slag will loosen and fall off, and together with the small particles of impurities left in the rotor, they will splash towards the stator side under the centrifugal force of the rotor rotation, and some small particles will be in the air. Flying out of the gap between the screen and the lower windshield, hitting the wire rod, causing damage to the wire rod surface

In addition, when inspecting the generator, the gap between the air ring plate and the wire rod is small, and the anti-corona layer on the surface of the wire rod will also be damaged during the disassembly process.

Images