| 摘要 |
<p>The invention relates to a method for detecting a short circuit relative to at least one phase (13a, 13b, 13c) of a protected object (11) in a multi-phase electrical power transmission grid, wherein current values are captured for each phase (13a, 13b, 13c) at at least two measurement points of the protected object (11), differential current values are determined for each phase (13a, 13b, 13c) from the current values, and an initiating signal for a certain phase (e.g., 13b) is generated if the differential current value of said phase (e.g., 13b) exceeds a threshold value. In order to provide a method that, despite close spatial proximity of the current transformer used for capturing the current values, provides a reliable and selective shut-off of only that or those phase(s) that is actually affected by a short circuit, the invention proposes that a stabilization current value is determined for each phase (13a, 13b, 13c) from the current values, and a blocking signal is generated for a particular phase (e.g. 13a, 13c) if the relevant stabilization current value is below a prescribed stabilization threshold, wherein the blocking signal suppresses the output of an initiating signal for the relevant phase (e.g., 13a, 13c). The invention further relates to a corresponding differential protection device.</p> |
