Functions
2.3 Directional Overcurrent Protection 67, 67N
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
109
During a busbar fault, the device that detects faults in reverse (busbar) direction using the directional relay
element 67-1 will block one of the non-directional overcurrent elements (50-1, 50-TOC) of devices at the oppo-
site end of the same feeder. In addition, a "Reverse" message is generated and transmitted via the auxiliary
voltage loop to the relay located at the opposite end of the line.
Figure 2-31 Reverse interlocking using directional elements
The directional overcurrent element providing normal time grading operates as selective backup protection.
The following figure shows the logic diagram for the generation of fault direction signals.
Figure 2-32 Logic diagram for the generation of fault direction signals
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