Protection functions
• Single and/or three-pole auto-reclosure• Synchro-check with live/dead line/bus measurement
• Closing under asynchronous conditions (consideration of CB operating time)
• Circuit-breaker failure protection with two stages (single and three-pole with/without current)
• End-fault protection
• Pole-discrepancy protection
• Overvoltage/undervoltage protection
Control function
• Commands for control of CB and isolatorsApplication
The 7VK61 provides highly flexible breaker management. It applies to singlebreaker, ring-bus, and 1½ breaker installations.
The auto-reclosure, synchronismcheck, breaker failure protection and voltage protection functions can be used separately or combined. Therefore the current and voltage transformer connection
can be selected according to the required application.
The auto-reclosure function closes the circuit-breaker after this circuit-breaker has tripped due to a fault. The checksynchronism function ensures that the two circuits being reconnected by closing the circuit-breaker are within a defined safe operating state before the CLOSE command is issued.
The numerical 7VK61 relay provides rapid backup fault clearance in case the circuit-breaker nearest to the fault fails to respond to a TRIP command.
It is suitable for power systems of all voltage levels with single and/or three-pole circuit breaker operation. The initiation signal can be issued from any protection or supervision equipment.
Information from the circuit-breaker auxiliary contact is only required for the breaker failure protection during faults which produce little or no fault current fl ow, for instance due to a trip
from the power transformer Buchholz protection.
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