ABB Relion REG670, Applications Manual

Page: 501 / 780

normally under more stable conditions and a longer operation time delay setting is
needed, where the
tSCM setting is used. During auto-reclosing, a shorter operation
time delay setting is preferable, where the tSCA setting is used. A typical value for
tSCM can be 1 second and a typical value for tSCA can be 0.1 seconds.
Energizingcheck settings
AutoEnerg and ManEnerg
Two different settings can be used for automatic and manual closing of the circuit
breaker. The settings for each of them are:
• Off , the energizing function is disabled.
• DLLB , Dead Line Live Bus, the line voltage is below set value of
ULowLineEnerg and the bus voltage is above set value of UHighBusEnerg .
• DBLL , Dead Bus Live Line, the bus voltage is below set value of ULowBusEnerg
and the line voltage is above set value of UHighLineEnerg .
• Both , energizing can be done in both directions, DLLB or DBLL .
ManEnergDBDL
If the parameter is set to On , manual closing is also enabled when both line voltage and
bus voltage are below ULowLineEnerg and ULowBusEnerg respectively, and
ManEnerg is set to DLLB , DBLL or Both .
UHighBusEnerg and UHighLineEnerg
The voltage level settings must be chosen in relation to the bus or line network voltage.
The threshold voltages
UHighBusEnerg and UHighLineEnerg have to be set lower
than the value at which the network is considered to be energized. A typical value can
be 80% of the base voltages.
ULowBusEnerg and ULowLineEnerg
The threshold voltages ULowBusEnerg and ULowLineEnerg , have to be set to a value
greater than the value where the network is considered not to be energized. A typical
value can be 40% of the base voltages.
A disconnected line can have a considerable potential due to, for
instance, induction from a line running in parallel, or by being fed via
the extinguishing capacitors in the circuit breakers. This voltage can
be as high as 30% or more of the base line voltage.
Because the setting ranges of the threshold voltages UHighBusEnerg /
UHighLineEnerg and ULowBusEnerg / ULowLineEnerg partly overlap each other, the
setting conditions may be such that the setting of the non-energized threshold value is
higher than that of the energized threshold value. The parameters must therefore be set
carefully to avoid overlapping.
1MRK 502 071-UEN -
Section 15
Control
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062 495
Application manual