Operating Quantity - ABB RELION REX640 Technical Manual

1MRS759142 C
4.12.5.5
REX640
Technical Manual
U
1
U U m
( )
unb = unb ⋅
U m
( )
1
GUID-31D1B143-46AA-4ED7-98BA-A67F05915D90 V1 EN
Level detector
The operating signal is compared to the set Start value. If the operating signal exceeds
the set Start value, Level detector sends an enabling signal to the Timer module.
Timer
Once activated, Timer activates the START output. The time characteristic is
according to DT. When the operation timer has reached the value set by Operate delay
time, the OPERATE output is activated if the operating signal persists. If a drop-off
situation happens, that is, the fault disappears before the operate delay is exceeded, the
timer reset state is activated. If the reset timer reaches the value set by Reset delay
time, the operation timer resets and the START output is deactivated.
Timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operation time. The value is available
in the Monitored data view.
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 which selects the blocking mode. The BLOCK input can be controlled
by a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode,
the operation 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 output is not activated.

Operating quantity

Operating quantity in ungrounded SCB
Consider a case of a standard ungrounded shunt capacitor bank as shown in
567.
Section 4
Protection functions
(Equation 246)
Figure
1053