Both hydropower and thermal power must have an exciter. The exciter is generally connected to the same large shaft as the generator. When the large shaft rotates under the drive of the prime mover, it simultaneously drives the generator and the exciter to rotate. The exciter is a DC generator that emits DC power, which is sent to the coil of the rotor through the slip ring of the rotor of the generator to generate a magnetic field in the rotor, thereby generating an induced potential in the stator of the generator. The exciter of the largest generator set is replaced by the self-shunt AC excitation system, most of which use the voltage of the generator outlet to pass the excitation change, pass through the rectifier device into direct current, and then send the current through the generator rotor slip ring. to the generator rotor. When this kind of system is used, the initial excitation of the generator should be carried out each time it is turned on, which is to add an initial excitation to the generator to establish the initial voltage of the generator.
The excitation of the old-fashioned exciter relies on its own remanence, which can make the exciter generate electricity, but the energy is very small and the voltage is very weak, but this weak current passes through the excitation coil of the exciter to strengthen the remanence. effect. This strengthened magnetic field continues to make the exciter generate electricity, which is more energy than the residual magnetism power generation, and then repeating this over and over again, the voltage emitted by the exciter can become higher and higher, that is to say, the electricity emitted by the exciter is first for itself. It is used to establish its own ability, and only supply the generator excitation when a certain high voltage is reached. The excitation system of modern large generator sets adopts a microcomputer excitation system, and its initial excitation is supplied by the initial excitation power supply, which is provided by the power grid or by the DC power supply of the power plant.
Post time: Jun-09-2022
