ABB RELION Series, Техническое руководство

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Restoring mode Description
Disabled Load restoration is disabled.
Auto In the “Auto” mode, input frequency is continuously compared to the Restore
start Val setting. The restore detection module includes a timer with the DT
characteristics. Upon detection of restoring, the operation timer activates the
ST_REST
output. When the timer has reached the value of the
Restore delay
time setting, the
RESTORE
output is activated if the restoring condition still
persists. If the frequency drops below the
Restore start Val before the
RESTORE
output is activated, the reset timer is activated. If the reset timer
reaches the value of the
Reset delay time setting, the timer resets and the
ST_REST
start output is deactivated.
Manual In the “Manual” mode, a manual restoration is possible through the
MAN_RESTORE
input or via communication. The
ST_REST
output is activated if
the
MAN_RESTORE
command is available and the frequency has exceeded the
Restore start Val setting. The manual restoration includes a timer with the DT
characteristics. When the timer has reached the set value of the Restore delay
time setting, the
RESTORE
output is activated if the restoring condition still
persists. If the frequency drops below the
Restore start Val setting before the
RESTORE
output is activated, the reset timer is activated. If the reset timer
reaches the value of the
Reset delay time setting, the timer resets and the
ST_REST
start output is deactivated.
A condition can arise where the restoring operation needs to be canceled. Activating
the
BLK_REST
input for the "Auto" or "Manual" modes cancels the restoring
operation. In the "Manual" restoring mode, the cancellation happens even if
MAN_RESTORE
is present.
Once the
RESTORE
output command is cancelled, the reactivation of
RESTORE
is
possible only after the reactivation of the
OPERATE
output, that is, when the next
load-shedding operation is detected.
Blocking logic
There are three operation modes in the blocking function. The operation modes are
controlled by the
BLOCK
input and the global setting in Configuration/System/
Blocking mode that selects the blocking mode. The
BLOCK
input can be controlled
with a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the
BLOCK
input signal activation is
preselected with the Blocking mode global setting.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode,
the operate timer is frozen to the prevailing value, but the
OPERATE
output is not
deactivated when blocking is activated. In the "Block all" mode, the whole function is
blocked and the timers are reset. In the "Block OPERATE output" mode, the function
operates normally but the
OPERATE
,
OPR_FRQ
and
OPR_FRG
outputs are not
activated.
4.5.2.5 Application
An AC power system operates at a defined rated frequency. The nominal frequency in
most systems in the world is 50 Hz or 60 Hz. The system operation is such that the
operating frequency remains approximately at the nominal frequency value by a small
1MRS758755 A
Section 4
Protection functions
REC615 and RER615 447
Technical Manual