FILTER FOR DIGITAL PROTECTIVE RELAY IN POWER SYSTEM AND DISTANCE RELAY IN POWER SYSTEM

摘要

PROBLEM TO BE SOLVED: To detect only the specified components of system high frequency, and remove other components completely, and flatten the inclination of amplitude-frequency property, by setting the fundamental transmission function of a digital filter so that it can be expressed in a specified formula. SOLUTION: The fundamental transmission function H6(Z) of a digital filter is set so that it can be expressed in a formula, where, (h) is sampling frequency/ inputted reference frequency, and (p) is a designated factor. Hereby, the degree of the digital filter becomes low degree, so this filter can detect only the specified high frequency components at high speed, and can remove other components completely. Moreover, this can flatten the inclination of amplitude-frequency property, by adding the specified factor (p) to the fundamental transmission function H6(Z).