Offline temperature characteristic detection method for SiC (Silicon Carbide) deexcitation resistor

Abstract

The invention discloses an offline temperature characteristic detection method for a SiC (Silicon Carbide) deexcitation resistor, belonging to the detection technology of SiC deexcitation resistors of synchronous generator excitation systems. The offline detection method is characterized by comprising the following steps of: connecting the SiC deexcitation resistor and a testing power supply according to a predetermined time length T; and meanwhile, monitoring the current, the voltage and the surface temperature value of the SiC deexcitation resistor by using an ammeter, a voltmeter and a thermodetector to obtain the temperature characteristic of the SiC deexcitation resistor, wherein the predetermined time length T for switching on the power supply is determined according to 20-50 percent of rated energy of the SiC deexcitation resistor. Aiming at the present circumstance that the complex online deexcitation testing detection method for the generator is adopted for the temperature characteristic of the SiC deexcitation resistor in China, the invention provides a new detection method which is economical and practical as well as safe and simple. Therefore, the SiC deexcitation resistor with defects can be found, the running deexcitation resistor is ensured in the sound condition, and the safety and the reliability of an excitation device and the generator are improved.

Description

technical field [0001] The invention relates to an excitation system of a synchronous generator, in particular to an off-line detection method for the temperature characteristic of a SiC demagnetization resistance. Background technique [0002] The de-excitation method of the synchronous generator excitation system has changed from the traditional switch de-excitation in the past to the de-excitation resistance discharge de-excitation. The safety of the de-excitation resistance is related to the safety of the excitation system, as well as the safety of the generator and the power system. [0003] According to the volt-ampere characteristics of the demagnetization resistance, the demagnetization resistance is divided into linear resistance and nonlinear resistance, and the nonlinear resistance is further divided into zinc oxide ZnO resistance and silicon carbide SiC resistance. Since SiC demagnetization resistors have "soft" volt-ampere characteristics, high allowable tempera...

AI Technical Summary

Problems solved by technology

[0006] These large-scale tests are extremely complicated, time-consuming and labor-intensive, and have certain risks, so few users adopt them.

That is to say, although SiC demagnetization resistors are widely used in large-scale power plants in my country, most users have not conducted any detection of their temperature characteristics, so that some SiC demagnetization resistors have burned out, affecting the operation safety of excitation devices and generators.

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