What are the common faults of reactors and how to repair them?

Reactor is used more and more in the system, which makes it often have some similar faults in operation. Based on years of operation experience, the author introduces several common faults and treatment methods.

Surface discharge

After the reactor operates in outdoor atmospheric conditions for a period of time, there will be dirt deposition on its surface. In foggy or rainy days, the surface dirt layer will be damped, which will increase the surface leakage current and generate heat. Due to the different speed of water evaporation, the local dry area appears on the surface, which causes the local surface resistance to change, and the current forms a local arc at the interruption. As the time goes on, the arc will merge and form a dendritic discharge along the surface. The turn to turn short circuit is the further development of dendritic discharge, that is, the current in the short line turns increases sharply, and the insulation of the line turns is damaged due to the rise of temperature.

In order to avoid dendritic discharge and turn to turn short circuit fault of outdoor reactor, the surface discharge can be greatly restrained by applying hydrophobic coating; the leakage current concentration on the lower surface can be overcome by embedding ring current sharing electrode at the end; the surface leakage current can be restrained to a certain extent by wearing rainproof cap and external rainproof layer. In addition, the frequency of cleaning the reactor surface and insulator surface should be increased in areas with serious pollution.

Local temperature too high

When the reactor is in operation, the temperature is too high, which accelerates the aging of polyester film. When the rainwater seeps into the crack of lead-in wire or cross epoxy, the mechanical strength will be lost, resulting in turn to turn short circuit and ignition.

The causes of reactor temperature rise are: welding quality problems, welding resistance of terminal and winding welding produces additional resistance and heating. In addition, due to the small design margin of temperature rise, the design value is very close to the temperature rise limit specified in the national standard. In addition to the design and manufacturing reasons, during operation, if the air passage of the reactor is blocked by foreign matters, resulting in poor heat dissipation, it will also cause local high temperature and fire.

In order to limit the temperature rise, the ventilation condition of reactor should be improved and the ambient temperature of reactor should be reduced. At the same time, the reactor should be shut down for maintenance regularly (the reactor surface and each vertical cooling air passage can be flushed with water column), so as to remove the accumulated dirt on the surface, keep the air passage unblocked, check the external insulation state in detail, and deal with the problems in time.

Vibration and noise fault

The vibration of iron core reactor becomes larger during operation, which causes looseness of fasteners and increase of noise. The main causes of vibration are the failure of magnetic circuit and the iron core is not compressed or the clamp is loose during manufacturing and installation. Generally, it only needs to tighten the fastener again. Sometimes, when the air core reactor is put into operation, the AC noise (the fundamental frequency is 100Hz) is very large, accompanied by rhythmic beat frequency, and the foundation is heated. This is because the strong alternating magnetic flux of air core reactor brings resonance, eddy current and heat to the surrounding steel components, especially the embedded parts of foundation. This is the fundamental problem in the design and installation of infrastructure construction, so we can only stop the operation and carry out thorough transformation.