ABB Relion 670 series, Техническое руководство

Страница: 576 / 1432

neutral point side and three phase voltage from the generator terminals. The maximum of the
three phase-to-phase voltages and maximum of the three phase currents are measured.
When the maximum phase-to-phase voltage is less than the
27_pick_up for the period tArm, it is
ensured that the generator is off-line. The Enabled signal will initiate the overcurrent function. If
the calculated maximum current of the three phases is larger than IPickup for the period tOC then
the TRIP signal becomes activated. Also PICKUP signal becomes activated when overcurrent is
detected.
When the maximum phase-to-phase voltage is larger than
59_Drop_out for a period longer than
tDisarm, it is ensured generator is on line. During this state, undervoltage operation is disarmed,
blocking the overcurrent operation and thus the function becomes inoperative.
BLOCK input can be used to block AEGPVOC (50AE). In addition, the BLKTR input that blocks the
TRIP signal is also present. The input BLKTR can be used if AEGPVOC (50AE) is to be used only for
monitoring purposes.
IPickup
Operation = Enabled
a
a>b
b
Imax_DFT
AND
BLOCK
TRIP
RI
Enabled
S
R NOUT
OUT
27_pick_up
a
a<b
b
Uph-ph_max_DFT
ON - Delay
59_Drop_out
a
a>b
b
ON - Delay
OR
AND
ANSI09000784-2-en.vsd
0
0-tOC
0
0-tArm
0
0-tDisarm
ANSI09000784 V2 EN-US
Figure 303: AEGPVOC (50AE) logic diagram
8.15.1.7 Technical data
GUID-9B1C0C10-8AF9-4D9E-8076-B3E1C238D29A v7
Table 310: AEGPVOC (50AE) technical data
Function Range or value Accuracy
Trip value, overcurrent (5-900)% of IBase ±1.0% of I
n
at I≤I
n
±1.0% of I at I>I
n
Reset ratio, overcurrent >95% at (20–900)% of IBase -
Transient overreach, overcurrent
function
<10% at τ = 100 ms -
Critical impulse time, overcurrent 10 ms typically at 0 to 2 x I
set
-
Impulse margin time, overcurrent 15 ms typically -
Table continues on next page
Section 8 1MRK 502 066-UUS B
Current protection
570
Technical manual