High-reliability deexcitation apparatus used for hydro-turbo generator set

Abstract

The invention provides a demagnetization device, in particular to a demagnetization device which has high reliability and is used for a water-turbine generator set. The device includes a three-phase full controlled rectifier bridge, a demagnetization switch, and a zinc oxide resistance which is connected with two ends of a generator rotor in parallel, wherein, the input terminal of the three-phase full controlled rectifier bridge is connected with the side edge of an excitation transformer; the original edge of the excitation transformer is connected with a generator stator end; and the output terminal of the three-phase full controlled rectifier bridge is connected with a generator rotor end by the demagnetization switch. The residual voltage of the zinc oxide resistance is smaller than the anode peak voltage at the AC side of the three-phase full controlled rectifier bridge. During normal demagnetization, the zinc oxide resistance is opened for demagnetization depending on the anode peak voltage of the three-phase full controlled rectifier bridge, and the demagnetization switch helijumps, therefore, no damage is caused to the contact thereof and an arc-extinguishing system, and the demagnetization without damage can be realized.

Description

technical field [0001] The invention relates to a demagnetization device, in particular to a high-reliability demagnetization device for a hydroelectric generating set. Background technique [0002] The so-called demagnetization system is the process of weakening the magnetic field energy generated by the excitation current in the rotor winding of the generator to as small as possible as soon as possible when the internal failure of the generator set is allowed by the rotor insulation. When a short circuit occurs inside the generator set or a short circuit fault occurs outside the generator, the demagnetization system can quickly reduce the induction potential of the generator and reduce the loss caused by the fault. The main requirement for the generator demagnetization system is to reliably and quickly consume the magnetic field energy stored in the generator, and at the same time limit the high overvoltage generated at both ends of the excitation winding to protect the sa...

AI Technical Summary

Problems solved by technology

Since the anode voltage can be as high as 1300 volts and the commutation peak voltage can be as high as 4200 volts, the excitation system often has problems, causing false strong excitation, resulting in an increase in the number of de-excitation switch operations

Therefore, many problems such as the refusal of the switch itself are exposed.

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