f
VoltagedipTm
slip
≤
−
⋅
( )
π δ
π
0
(Equation 275)
f
slip
Slip frequency
δ
0
Swing angle at the outer blinder
VoltagedipTm Set
V dip time
Otherwise, OPERATE is activated on the way out, when the impedance exits an outer
blinder and the swing repeats for the set
Max number slips
count in the respective
enabled zone that the swing has passed through.
If the
Swing time
has elapsed but the impedance exits the inner blinder and
continues through the opposite blinders without passing through the mho circle,
the SWING output is activated. The SWING output remains activated for a time
determined by the
Reset time
setting unless another swing occurs before the reset
time expires causing the output to remain active for another
Reset time
interval. If
this swing is repeated for the set
Max Num slips Zn3
count and the
Zone 3 enable
setting is “Yes”, the SWING_OP output is activated. The SWING_OP output remains
activated for a time determined by the
Operate dropout time
setting.
If the “Adaptive” option is selected and an OSB condition is not detected, but
the impedance enters the mho circle after remaining between the inner and outer
blinders for greater than 1.5 cycles, the function assumes a severe swing and assert
the OPERATE output.
The drop out delay for OPERATE output can be set by
Operate dropout time
setting.
If the polarity of the voltage signal is opposite to the normal polarity, the correction
can be done by setting
Voltage reversal
to “Yes”, which rotates the impedance
vector by 180 degrees.
The DISABLE input can be used to coordinate the correct operation during the
start-up situation. The function is blocked by activating the DISABLE signal. Once
the DISABLE signal is deactivated, the function remains blocked (outputs disabled)
for additional time duration as set through the setting
Disable time
.
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.
1MRS759142 F
Protection functions
REX640
Technical Manual
1011
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