| 摘要 |
PURPOSE:To improve frequency characteristics by a method wherein the sampling of a system input signal is effected with a given interval and an effective value is obtained from the data of sampling by the simple operation of multiplication, summation and subtraction. CONSTITUTION:A protective relay device is constituted of a sampling circuit 1, an A/D converter 2, an operating circuit 3, a discriminating circuit 4 and a CPU 5. A sampling data of a system input signal is obtained by the sampling circuit 1. Subsequently, operation is effected by the operating circuit employing a present data and data to 5 times before In-In-5. Operating argorithm are In-2.In-3. In.In-5-In-1.In-3+In.In-4. The result of operation is the (3<1/2>-1) times of the square of system input and it is not depending on the initial phase angle of the sampling. An error with respect to a frequency fluctuation is very small. |
