Fuse fail
Fuse fail Line Voltage
Line Bus Voltage
Line
reference
voltage
Bus voltage
52
ANSI10000079-2-en.vsd
SynchroCheck
VHighBusSC > 50 – 120% of GblBaseSelBus
VHighLineSC >50 – 120% of GblBaseSelLine
VDiffSC < 0.02 – 0.50 p.u.
PhaseDiffM < 5 – 90 degrees
PhaseDiffA < 5 – 90 degrees
FreqDiffM < 3 – 1000 mHz
FreqDiffA < 1000 mHz
ANSI10000079 V2 EN-US
Figure 116: Principle for the synchronism check function
12.1.2.3 Energizing check
M12310-3 v12
The main purpose of the energizing check function is to facilitate the controlled re-
connection of disconnected lines and buses to energized buses and lines.
The energizing check function measures the bus and line voltages and compares them
to both high and low threshold values. The output is given only when the actual
measured conditions match the set conditions. Figure
117 shows two substations,
where one (1) is energized and the other (2) is not ener
gized. The line between CB A
and CB B is energized (DLLB) from substation 1 via the circuit breaker A and
energization of station 2 is done by CB B energization check device for that breaker
DBLL. (or Both).
1MRK 505 370-UUS A Section 12
Control
Busbar protection REB670 2.2 ANSI 297
Application manual
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