Method for judging turn-to-turn short circuit fault position and number of short circuit turns of steam turbine generator rotor

Abstract

The invention relates to a method for judging a turn-to-turn short circuit fault position and the number of short circuit turns of a steam turbine generator rotor, belonging to the field of master equipment relay protection of a power system. The method is characterized by comprising the following steps of: calculating a fault by utilizing a generator rotor turn-to-turn fault analysis technology based on a multi-loop model, preferentially selecting a detection object, and determining the criterions of the fault type and the fault position of the rotor by utilizing an effective value and a phase angle of a characteristic harmonic component; fitting on the basis of a calculating result to obtain a functional relation between stator branch fault characteristic harmonic current of windings indifferent slots during short-circuit and the number of short circuit turns; and determining the number of the short circuit turns through acquiring the current of a branch of the stator from a generator end, filtering the effective value and the phase angle of the fault characteristic harmonic component of the branch current through fast Fourier analysis, determining the fault position according to the criterions of the fault type and the fault position and solving an equation consisting of the functional relation consisting of the stator branch fault characteristic harmonic current and the number of short circuit turns.

Description

technical field [0001] The invention belongs to the technical field of relay protection for main equipment of a power system, and in particular relates to a method for judging the short-circuit fault position of a rotor winding of a turbogenerator and calculating the number of short-circuit turns based on the harmonic analysis of stator branch currents. Background technique [0002] Turn-to-turn short circuit of the rotor winding is a common electrical fault of large turbogenerators. A slight fault will not have a serious impact on the generator, but if it operates with a fault for a long time, local overheating at the short circuit will lead to deterioration of the fault and cause excitation The increase of current, the decrease of reactive power output, and the intensification of vibration of the unit have brought serious safety hazards to the generator set and power system. In the 1990s, 3 of the 4 300MW generators in a thermal power plant in my country were magnetized du...

AI Technical Summary

Problems solved by technology

The traditional methods for detecting inter-turn short-circuit faults of generator rotor mainly include: open transformer method, AC impedance and power loss method, DC impedance method, no-load and short-circuit characteristic test method, etc. These detection methods cannot be detected under actual operating conditions.

Although the differential coil dynamic measurement method can realize online detection, it needs to install additional devices

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