This unit is used for the single and threepole auto-reclosure of a circuit-breaker, after this circuit-breaker has tripped due to a fault. The synchro-check 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 SIPROTEC 7VK61 is also applicable as circuitbreaker failure protection. A breaker failure occurs when the circuit-breaker fails to correctly open and clear the fault after single or three-pole trip commands have been issued by the protection. It is then necessary to trip the relevant busbar zone (section) to ensure fault clearance. Together with the above-mentioned protection functions, the following additional functions of the SIPROTEC 7VK61 can be applied: end-fault protection, pole-discrepancy protection, overvoltage protection and undervoltage protection. As a member of the numerical SIPROTEC 4 relay family, it also provides control and monitoring functions and therefore supports the user with regard to a cost-effective power system management.

Hardware

• Binary inputs: 7/20
• Binary outpurs: 5/18
• Text display
• Surface-mounting or flush-mounting housing

Communication interfaces

• System port 
  – IEC 61850

  – IEC 60870-5-103 
  – PROFIBUS DP
  – DNP 3
  

• Service port
  – DIGSI 4
  – Modem
• Front port
  – DIGSI 4
• Time synchronization via IRIG B, DCF 77 or system interface

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 f. ctrl. of CB and isolators

Monitoring functions

• Operational measured values

• Self-supervision of the relay

• Event buffer and fault protocols

• Oscillographic fault recording

• Monitoring of CB auxiliary contacts

• Switching statistics

Features

• All functions can be used separately

• Initiation/start by phase-segregated or 3-pole trip commands

• Auto-reclosure for max. 8 reclose cycles

• Evolving/sequential trip recognition

• Auto-reclosure with ADT, DLC, RDT

• Synchro-check with ΔV, Δϕ , Δf measurement

• Breaker failure protection with highly secure 2-out-of-4 current check detectors

• Breaker failure protection with short reset time and negligible overshoot time