SKYDDSRELEANORDNING FOR ETT ELEKTRISKT KRAFTSYSTEM

摘要

A static circuit comprising an input transformation circuit responsive to current or voltage derived from an electric power system to be protected for producing a first pair of electric quantities having a phase difference of theta and a second pair of electric quantities dephased by phi from the first pair of electric quantities respectively, a pair of multipliers for the producing products of the first and second pair of electric quantities, and an adder or subtractor for producing the difference of these products.