| 摘要 |
<p>The invention refers to method for fault detection in a power transformer/autotransformer and/or interconnected power lines, which are within the zone protected by the differential protection, and particularly suitable for detecting turn-to-turn faults in power transformer/autotransformer windings. The method according to the invention is achieved by measuring all individual instantaneous phase currents of the protected object, calculating individual phase currents as fundamental frequency phasors, calculating the contributions of the individual protected object sides negative sequence currents to the total negative sequence differential current by compensating for the phase shift of an eventual powe r transformer within the protected zone, comparing the relative positions of t he compensated individual sides negative sequence currents in the complex plane , in order to determine whether the source of the negative sequence currents, i.e. the fault position, is within the protected zone or outside of the protected zone, delimited with current transformer locations, disconnecting the protected object if determined that the source of the negative sequence currents is within the protected zone.</p> |
