ZnO and SiC composite circuit for generator rotor de-excitation and overvoltage protection

Abstract

A ZnO and SiC composite circuit for generator rotor de-excitation and overvoltage protection is characterized in that a ZnO non-ohmic resistor (1) and an SiC non-ohmic resistor (2) are adopted to form a series branch, the series branch and an SiC non-ohmic resistor (3) are connected in parallel to form a series-parallel component for realizing the reliable and fast de-excitation of the generator set, and effective limitation on the rotor overvoltage. By adopting the de-excitation component provided by the invention to replace the conventional single ZnO or SiC de-excitation component, a fast fuse is not needed to be connected in series, the occupied area is smaller than one third of that of the single ZnO non-ohmic resistor, and an expensive magnetic field circuit breaker with high fracture arc voltage is not needed any more, instead, an ordinary magnetic field circuit breaker can meet the demands. The invention improves the energy and capacity utilization ratio of the SiC non-ohmic resistor, reduces the resistor amount by two thirds compared with the single SiC non-ohmic resistor de-excitation mode, and doubles the de-excitation speed.

Description

technical field [0001] The patent of the invention relates to a technology for generator rotor demagnetization and overvoltage protection, specifically a series-parallel composite circuit composed of ZnO (zinc oxide) non-linear resistors or SiC (silicon carbide) non-linear resistors to realize the generator set Reliable and fast de-excitation and effective limitation of rotor overvoltage. Background technique [0002] In recent years, accidents of generators and main transformers burning have occurred frequently. With the increase of single unit capacity of large-scale synchronous generators, rapid removal of fault current is an important condition to ensure the stable and safe operation of the power system, especially when the internal or external generator (Including machine-end transformer, excitation transformer and main transformer, export bus, etc.) When a short circuit or ground fault occurs, the excitation current must be cut off quickly, and the energy stored in the...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem of using a single ZnO nonlinear resistor or SiC nonlinear resistor to demagnetize, the patent of this invention combines the advantages of ZnO and SiC nonlinear resistors, and makes up for their respective shortcomings through complementary advantages. A composite circuit composed of ZnO non-linear resistors and SiC non-linear resistors connected in series and in parallel provides an ideal solution for generator sets to achieve reliable and fast demagnetization and effectively limit rotor overvoltage

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