Siemens SIPROTEC 4 7VK61 Manual page 23

Circuit Breaker Failure Protection (optional)
•
With definite time current stages for monitoring the current flow through every pole of the circuit
breaker
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Separate pickup thresholds for phase and earth currents
•
Independent timers for single-pole and three-pole tripping
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Start by trip command of every internal protection function
•
Start by external trip functions possible
•
Single-stage or two-stage
•
Short dropout and overshoot times
Voltage Protection (optional)
•
Overvoltage and undervoltage detection with different stages
•
Two overvoltage stages for the phase-earth voltages
•
Two overvoltage stages for the phase-phase voltages
•
Two overvoltage stages for the positive sequence voltage
•
Two overvoltage stages for the negative sequence voltage
•
Two overvoltage stages for the zero sequence voltage or any other single-phase voltage
•
Settable dropout to pickup ratios
•
Two undervoltage stages for the phase-earth voltages
•
Two undervoltage stages for the phase-phase voltages
•
Two undervoltage stages for the positive sequence voltage
•
Settable current criterion for undervoltage protection functions
User-defined Logic Functions (CFC)
•
Freely programmable combination of internal and external signals for the implementation of user-
defined logic functions
•
All typical logic functions
•
Time delays and limit value inquiries
Command Processing
•
Switchgear can be switched on and off manually via local control keys, the programmable function keys
on the front panel, via the system interface (e.g. by SICAM or LSA), or via the operator interface (using a
personal computer and the operating software DIGSI)
•
Feedback on switching states via the circuit breaker auxiliary contacts (for commands with feedback)
•
Monitoring of the circuit breaker position and of the interlocking conditions for switching operations.
Monitoring Functions
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Availability of the device is greatly increased because of self-monitoring of the internal measurement
circuits, power supply, hardware and software
•
Monitoring of the current and voltage transformer secondary circuits by means of summation and
symmetry checks
•
Trip circuit supervision
•
Checking for the measured direction and the phase sequence.
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018
Introduction
1.3 Characteristics
23