13.1.2.3 Energizing check
M12310-3 v11
The main purpose of the energizing check function is to facilitate the controlled re-connection
of disconnected lines and buses to energized lines and buses.
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 90 shows two substations, where one (1) is energized and the
other (2) is not energized. 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).
1 2
A
EnergizingCheck
UHighBusEnerg > 50 - 120 % of GblBaseSelBus
UHighLineEnerg > 50 - 120 % of GblBaseSelLine
ULowBusEnerg < 10 - 80 % of GblBaseSelBus
ULowLineEnerg < 10 - 80 % of GblBaseSelLine
UMaxEnerg < 50 - 180 % of GblBaseSelBus and/or
GblBaseSelLine
Line voltageBus voltage
IEC10000078-4-en.vsd
B
IEC10000078 V4 EN-US
Figure 90: Principle for the energizing check function
The energizing operation can operate in the dead line live bus (DLLB) direction, dead bus live
line (DBLL) direction, or in both directions over the circuit breaker. Energizing from different
directions can be different for automatic reclosing and manual closing of the circuit breaker.
For manual closing it is also possible to allow closing when both sides of the breaker are dead,
Dead Bus Dead Line (DBDL).
The equipment is considered energized (Live) if the voltage is above the set value for
UHighBusEnerg
or
UHighLineEnerg
of the base voltages
GblBaseSelBus
and
GblBaseSelLine
,
which are defined in the Global Base Value groups; in a similar way, the equipment is
considered non-energized (Dead) if the voltage is below the set value for
ULowBusEnerg
or
ULowLineEnerg
of the Global Base Value groups. A disconnected line can have a considerable
potential due to factors such as induction from a line running in parallel, or feeding via
extinguishing capacitors in the circuit breakers. This voltage can be as high as 50% or more of
the base voltage of the line. Normally, for breakers with single breaking elements (<330 kV) the
level is well below 30%.
When the energizing direction corresponds to the settings, the situation has to remain
constant for a certain period of time before the close signal is permitted. The purpose of the
delayed operate time is to ensure that the dead side remains de-energized and that the
condition is not due to temporary interference.
13.1.2.4 Voltage selection
M12321-3 v10
The voltage selection function is used for the connection of appropriate voltages to the
synchrocheck, synchronizing and energizing check functions. For example, when the IED is
used in a double bus arrangement, the voltage that should be selected depends on the status
of the breakers and/or disconnectors. By checking the status of the disconnectors auxiliary
Section 13 1MRK 511 358-UEN A
Control
228
Application manual
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