| 摘要 |
PURPOSE:To avoid an error action at the time of the saturation of a current transformer and obtain exact working characteristic, by a method wherein differential current data and the value of a suppression function are compared with each other, and wherein stopping output is generated at the time of a specific state, and wherein the stopping output is extinguished at the time of another specific state. CONSTITUTION:Respective terminal current data Dj are brought, and by a suppression data producing means 2, suppression data Dr are produced, and the data Dr of a different sample time are used, and by a suppression function computing means 3, a suppression function f(r) is produced. A comparing means 4 is provided with a first detecting means working when data Dd are on one side polarity and are greater than a specified relation to the function f(r), and a second detecting means working when the data Dd are on the other side polarity and are greater than the specified relation to the function f(r). Besides, when both the detecting means are worked, then stopping output to a differential relay means 5 is forced to be extinguished.
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