Siemens Siprotec 4 SIPROTEC 7VK61 Protection Relay

The SIPROTEC 4 breaker management relay 7VK61 is a highly flexible autorecloser, synchro-check, and circuit breaker failure protection unit. This unit is used for the single and three pole 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 7VK61 is also applicable as circuit breaker 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 7VK61 can be applied: end-fault protection, pole-discrepancy protection, overvoltage protection and under voltage 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.

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

COMMUNICATION INTERFACES

• Front interface for connecting a PC
• System interface for connecting to a control system via various protocols
  – IEC 61850 Ethernet
  – IEC 60870-5-103 protocol
  – PROFIBUS-FMS/-DP
  – DNP 3.0
• Rear-side service/modem interface
• Time synchronization via
  – IRIG-B or DCF77 or system interface

SIPROTEC 4 leads the way in integrating protection, control, measurement, and automation functions in one device. The homogenous system platform, the unique DIGSI 4 engineering program, and extensive experience of more than a million successfully operating devices in the field worldwide – thanks to these unique advantages, SIPROTEC 4 enjoys top recognition among users worldwide. SIPROTEC 4 is the industry standard for digital protection technology today in all fields of application.