| 摘要 |
PURPOSE:To provide a digital ratio differential relay in which detection sensitivity is enhanced and probability of erroneous function is reduced over a wide range. CONSTITUTION:The digital ratio differential relay has a polyline ratio characteristics comprising a line of characteristic 1 corresponding to a simple differential element region for setting a tap value constant while taking account of analog part fixed component error and quantized error of the relay, a line of characteristic 2 corresponding to a first ratio differential element region for setting a suppression ratio while taking account of analog part proportional component error, and a line of characteristic 3 corresponding to a second ratio differential element region for setting a suppression ratio while taking account of full-scale over. |
