De-excitation and over-voltage protection device for generator rotor

Abstract

A generator rotor demagnetization and overvoltage protection device relates to an overvoltage protection device for a thyristor rectification excitation system. It includes a demagnetization switch, a peak overvoltage absorber, a non-linear resistor, a thyristor trigger, a thyristor, a diode, a current transformer, a linear resistor, and one end of the demagnetization switch and one end of the peak overvoltage absorber Connect the rectifier power supply after connection, the other end is connected to one end of the linear resistance, one end of the linear resistance and one end of the non-linear resistance, the other end of the linear resistance and the other end of the non-linear resistance are connected in parallel, and then one end of the diode and one end of the thyristor are connected, and the other end of the linear resistance is connected to the The SCR trigger and the SCR trigger are respectively connected to the other end of the SCR, the other end of the diode and one end of the current transformer, and the other end of the current transformer is connected to the other end of the peak overvoltage absorber and then connected to the rotor winding. The invention not only has strong demagnetization ability and fast demagnetization speed, but also has fast overvoltage protection action, can avoid rotor winding open circuit, and effectively prevent the occurrence of rotor winding insulation breakdown accidents.

Description

technical field [0001] The invention relates to the technical field of generator rotor demagnetization and overvoltage protection, in particular to an overvoltage protection device for a thyristor rectification excitation system. Background technique [0002] The excitation power supply must be cut off quickly when the generator set or the outlet of the generator fails or is shut down normally. Since the rotor winding is a large inductance for energy storage, the sudden change of the excitation current will inevitably cause a considerable transient overvoltage at both ends of the rotor winding. , causing rotor insulation breakdown, so the rotor inductance must be demagnetized as soon as possible. For the thyristor rectification excitation system, the generator will not run in full phase or have a large slip due to non-full-phase or non-synchronous closing of the generator circuit. The difference is not running. Under these two operating conditions, severe overvoltage will be...

AI Technical Summary

Problems solved by technology

[0002] The excitation power supply must be cut off quickly when there is a fault in the generator set or at the outlet of the generator and it is shut down normally. Since the rotor winding is a large inductance for energy storage, the excitation current The sudden change will inevitably cause a considerable transient overvoltage at both ends of the rotor winding, resulting in rotor insulation breakdown, so the rotor inductance must be demagnetized as soon as possible. Closing and other reasons will cause the generator to operate in non-full phase or with a large slip difference. Under these two operating conditions, severe overvoltage will be generated in the rotor winding, because at this time the energy of the grid and the excitation power supply can be transmitted to the generator. In the rotor winding, the energy transport exceeds the demagnetization energy of the demagnetization device. When all the fuses in the demagnetization device are blown, the rotor winding is open. At this time, the rotor winding is equivalent to a constant current source, and the generated overvoltage will break down the rotor. Winding insulation, causing damage to unit equipment

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