Design Method of Excitation System Based on Time Constant of Excitation Rotor Loop

Abstract

The invention provides a novel excitation loop design method for a large-scale synchronous generator. The method can guarantee consistency of rise speeds of excitation currents when self-shunt excitation units of different manufacturers, which have different parameters, perform excitation so as to guarantee a success rate of excitation. The method is characterized in that a current-limiting resistor is designed on a direct current side of a conventional excitation loop to adjust an excitation-rotor loop time constant so as to guarantee excitation success of the synchronous generator. According to the novel design method, firstly, based on an excitation regulator, a synchronous voltage is accurately detected; according to a principle that a current provided by the excitation loop reaches 20% of current intensity of i(infinity) within 5 seconds, the excitation-rotor loop time constant T is determined; and a resistance value of the current-limiting resistor is determined via computing so as to calculate a secondary voltage and a capacity of an excitation transformer, thereby completing the design of main components of the execution loop.

Description

technical field [0001] The invention relates to a new method for designing an excitation circuit, which belongs to the technical field of large-scale synchronous generators in self-shunt excitation mode. Background technique [0002] The self-shunt excitation system is currently the most representative excitation method, and its excitation power is taken from the generator end, so when the residual voltage of the generator itself is not enough to supply the generator to maintain the initial excitation of self-excitation, it must be designed separately The excitation circuit of the generator provides the initial excitation current to the generator, so that the generator can establish a certain initial voltage. [0003] In the power industry standard DL / T 583 "Technical Conditions for Static Rectification and Excitation Systems and Devices of Large and Medium-Sized Hydrogenerators", the requirements for the excitation power supply are "the capacity configuration of the excitat...

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Problems solved by technology

[0005] However, in fact, due to the inductance of the rotor winding, the current cannot change abruptly, and gradually rises exponentially; the rotor time constants of generators produced by various generator manufacturers are different in varying degrees, resulting in large differences in the rate of current rise

The excitation circuit configured by the above traditional design and calculation method is an ideal excitation current value with infinite time, which cannot ensure the success of excitation within a fixed time on the project site

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