4.35
Date Code 20081022
Instruction Manual
SEL-787 Relay
Protection and Logic Functions
Basic Protection
The residual time-overcurrent elements, 51G1T and 51G2T, respond to
residual currents IGW1 and IGW2 as shown
.
Figure 4.16
Residual Time-Overcurrent Elements 51G1T and 51G2T
The negative-sequence time-overcurrent element 51Q
n
T responds to the 3I2
current as shown
Table 4.11
Winding n Negative-Sequence Time-Overcurrent Settings
(n = 1, 2)
Setting Prompt
Setting Range
Setting Name :=
Factory Default
NSEQ TOC LEVEL
OFF, 0.50–16.00 A
a
,
0.10–3.20 A
b
a
For I
NOM
= 5 A.
b
For I
NOM
= 1 A.
51Q
n
P :=OFF
51Q
n
P := OFF
NSEQ TOC CURVE
U1, U2, U3, U4, U5, C1, C2,
C3, C4, C5
51Q
n
C := U3
NSEQ TOC TDIAL
0.50–15.00
c
,
0.05–1.00
d
c
For 51_C := U_.
d
For 51_C := C_.
51Q
n
TD := 3.00
EM RESET DELAY
Y, N
51Q
n
RS := N
CONST TIME ADDER
0.00–1.00 sec
51Q
n
CT := 0.00
MIN RESPONSE TIM
0.00–1.00 sec
51Q
n
MR := 0.00
NSEQ TOC TRQCTRL
SEL
OGIC
51Q
n
TC := 1
51GnP
|IGWn|
Setting
51GnTC
Torque Control Switch
SEL
OGIC
Torque Control
Pickup
Curve
Timeout
Reset
51GnP
51GnR
51GnT
51GnTC
Torque Control
State Switch
Position
Logical 1
Closed
Logical 0
Open
Setting
51GnRS =
Reset Timing
Y
Electromechanical
N
1
Cycle
Relay
Word
Bits
SEL
OGIC
Setting
(From Figure 4.14)
Note: 51G1T element shown above; 51G2T is similar.
51G1T Residual
Time-Overcurrent Element
Curve Timing and Reset Timing
51GnP Pickup
51GnC Curve
Type
51GnTD Time
Dial
51GnRS Electromechanical
Reset? (Y/N)
51GnCT
Const. Time Add.
51GnMR Min.
Response
Settings
Summary of Contents for SEL-787
Page 1: ...20081022 SEL 787 Transformer Protection Relay Instruction Manual PM787 01 NB ...
Page 6: ...This page intentionally left blank ...
Page 12: ...This page intentionally left blank ...
Page 18: ...This page intentionally left blank ...
Page 78: ...This page intentionally left blank ...
Page 206: ...This page intentionally left blank ...
Page 280: ...This page intentionally left blank ...
Page 334: ...This page intentionally left blank ...
Page 376: ...This page intentionally left blank ...
Page 388: ...This page intentionally left blank ...
Page 474: ...This page intentionally left blank ...
Page 508: ...This page intentionally left blank ...