Once the electromagnet loses its magnetism, it will inevitably affect its work. In order to prevent the electromagnet from losing its magnetism, we must first understand the reason why the electromagnet loses its magnetism. The reasons that make the electromagnet lose its magnetism include: rotor winding failure, exciter failure, active excitation switch accidental tripping, damage to some components in the semiconductor excitation system or circuit failure and misoperation. The damage of the electromagnet losing its magnetism is mainly reflected in the damage of the generator itself and the power system!
Electromagnet
Damage to the generator itself:
(1) After the generator loses magnetization, the leakage flux at the end of the stator increases, causing the end and the end core to overheat.
(2) After asynchronous operation, the equivalent reactance of the generator decreases and changes from to. Therefore, the additional reactive power absorbed from the system can cause the stator windings to overheat.
(3) The difference frequency current presented by the generator rotor winding produces rated loss in the rotor winding, which causes the rotor winding to heat up.
(4) For large-scale direct cooling turbine generators, the maximum average asynchronous torque is small, the inertia constant is low, and the rotor is obviously asymmetric in both longitudinal and transverse directions. Due to these factors, the torque and active power of the excitation loss generator will swing violently under heavy load. For hydroelectric generators, this impact is even more serious.
Electromagnet
Damage to the power system:
(1) After the generator loses its magnetization, the active power will swing and the system voltage will drop, which may cause the adjacent normal operating generators to lose synchronization with the system, which will cause the system to vibrate.
(2) Many reactive powers in the generator loss-of-excitation system are insufficient. When the reactive power storage in the system is insufficient, the voltage will drop. In severe cases, the voltage will collapse and the system will split.
(3) The generator loses the excitation voltage and reduces its voltage. Other generators in the system will increase their reactive power output under the action of the active adjustment of the excitation equipment. As a result, some generators, transformers, and transmission lines have overcurrents, and backup maintenance may expand the fault range due to overcurrents.
Once the electromagnet loses its magnetism, it will not only affect the work, but also damage the generator and electrical system. Therefore, when using a generator, it is necessary to prevent the electromagnet from losing its magnetism. After reading this article, you must know how to prevent it. The electromagnet has lost its magnetism! I hope to help you!
