Research On Parameter Optimization Of Protection And Automation Devices Of Large Generator Unit Connected With Power System

In recent decades, electrical power industry booms fast with the developing economy. The scale of power system and the volume of generators become larger and larger, also the level of voltage becomes higher and higher. Not far from now, it will be combined to one unified power grid in our country. It becomes a hot study to improve the security and stability of power system. In recent years, power grid disintegrated several times because of the disturbance of voltage and frequency. It can cause vast area power failure and economic losses. In this background, is has important sense to research protections related to power network.The protections related to power network mention in this paper refer to all sorts of protections of generators such as loss-of-field protection, out-of-step protection, over and low voltage protection and abnormal frequency protection must have margin, cannot operate timelessness and coordinate with automation devices optimally so as to insure entire network secure. Base on analyzing and researching at home and abroad available large-scale generator protection related to network, this paper present a suit of review and parameter optimization method of protection and automation device. And further exploit a management system of protection related to network.This paper analyzes and researches the principle and application of over-voltage and low-voltage of generator stator, over-frequency and low frequency of generator, AVR, PSS, loss-of-field protection and out-of-step protection. According to Electrical Network Dispatching System Security Assessment and Protection and Automation Device Technology Rules, protection must not destroy the security and stability of power system, loss-of-field protection must not operate falsely when generator is operating in leading phase modal. This paper bring forward a review criterion of loss-of-field protection. Because traditional low-frequency load reduction method cannot restrain frequency descent, this paper present a new low-frequency load reduction method which base on variable ratio of frequency and voltage. The formula...