Insulation monitoring and positioning device and method for main shaft of generator

Abstract

The invention discloses an insulation monitoring and positioning device for a main shaft of a generator. The insulation monitoring and positioning device comprises a shaft current detection module, an insulation voltage detection module and a processing module, wherein the shaft current detection module detects shaft current of a turbine end of the main shaft of the generator; the insulation voltage detection module detects insulation voltage of a plurality of excitation-end ground insulation parts of the main shaft of the generator; the processing module processes the shaft current and the insulation voltage and outputs a main shaft low-insulation alarm signal when the shaft current is higher than a first default value and any insulation voltage is lower than a second default value, and the ground insulation part corresponding to the insulation voltage is positioned and displayed. Low-insulation monitoring of the main shaft of the generator is realized by measuring the shaft current of the main shaft of the generator and the insulation voltage of the excitation-end ground insulation parts, and an insulation-reduced part is positioned by measuring the shaft current and the insulation voltage, so that the measurement is accurate and the insulation-reduced part can be positioned timely and accurately.

Description

technical field [0001] The invention relates to the safety detection of the large shaft of the rotating rotor of the steam turbine generator, in particular to the insulation monitoring and fault location of the large shaft of the rotating rotor of the steam turbine generator. Background technique [0002] Existing methods for monitoring the insulation of the main shaft of the generator often have various disadvantages, which make the measurement results not accurate enough, and the fault part cannot be located. E.g: [0003] Application No. 200880124128.1 discloses a method for monitoring the shaft current and / or insulation of the shaft of an electric machine and a device for implementing the method. Rogowski coils are used to measure the relevant shaft current, and the measured shaft voltage and the relevant shaft current are measured. The results are used to determine the impedance and phase relationship between the two. If the limit value of the impedance is undershoot, ...

AI Technical Summary

Problems solved by technology

[0006] To sum up, most of the existing main shaft insulation monitoring based on the principle of generator shaft current monitoring use a single measurement as the criterion for judging the reduction of the generator main shaft insulation. It can be known that the insulation of the main shaft of the generator is reduced, and the location of the insulation reduction cannot be directly monitored and located. Human intervention is required, which affects the accident handling time and post-accident fault analysis, and affects the safe and stable operation of the unit.

During the start-up process of the generator, due to the friction of high-pressure water vapor on the main shaft of the generator, a large amount of charge accumulation is caused or the interference signal generated by the main magnetic field of the generator is easy to cause false alarms

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