1 Introduction
28
7SA522 Manual
C53000-G1176-C155-3
• Alternatively, check of the de-energized state before reclosing
• Closing at asynchronous system conditions with prediction of the synchronization
time
• Settable minimum and maximum voltage
• Verification of the synchronous conditions or de-energized state also possible
before the manual closing of the circuit breaker, with separate limit values
• Also measurement via transformer
• Measuring voltages optionally phase-phase or phase-earth
Voltage Protection
(optional)
• Overvoltage and undervoltage detection with different stages
• Two overvoltage stages for the phase-earth voltages, with common time delay
• Two overvoltage stages for the phase-phase voltages, with common time delay
• Two overvoltage stages for the positive sequence voltage, with a time delay each,
optionally with compounding
• Two overvoltage stages for the negative sequence voltage, with a time delay each
• Two overvoltage stages for the zero sequence voltage or any other single-phase
voltage, with a time delay each
• Settable drop-off to pick-up ratios for the overvoltage protection functions
• Two undervoltage stages for the phase-earth voltages, with common time delay
• Two undervoltage stages for the phase-phase voltages, with common time delay
• Two undervoltage stages for the positive sequence voltage, with a time delay each
• Settable current criterion for undervoltage protection functions
Frequency Protec-
tion (optional)
• Monitoring on underfrequency (f<) and/or overfrequency (f>) with 4 frequency limits
and delay times that are independently adjustable
• Very insensitive to phase angle changes
• Large frequency range (approx. 25 Hz to 70 Hz)
Fault Location • Initiated by trip command or reset of the pickup
• Computation of the distance to fault with dedicated measured value registers
• Fault location output in ohm, kilometers or miles and % of line length
• Parallel line compensation can be selected
• Taking into consideration the load current in case of single-phase earth faults fed
from both sides (settable)
Circuit Breaker
Failure Protection
(optional)
• With definite time current stages for monitoring current flow through every pole of
the circuit breaker
• With definite time monitoring time steps for single-pole and three-pole tripping
• Start by trip command of every internal protection function
• Start by external trip functions possible
• Single-stage or two-stage
To Next Page
Loading...
