
4.24
SEL-351A Relay
Instruction Manual
Date Code 20080213
Loss-of-Potential, Load Encroachment, and Directional Element Logic
Directional Control for Neutral-Ground and Residual-Ground Overcurrent Elements (Not in SEL-351A-1)
q
;
w
to
and
.
Figure 4.12
Zero-Sequence Voltage-Polarized Directional Element (Low-
Impedance Grounded Systems)
The 3V
0
may be either a calculated value (when global
settings VSCONN = VS and PTCONN = WYE) or a measured value (when
global setting VSCONN = 3V0). See
Zero-Sequence Voltage Sources on
I
N
3V
0
If Z0F Setting
>
0, Forward Threshold = 1.25 • Z0F — 0.25 •
I
N
3V
0
If Z0F Setting
≤
0, Forward Threshold = 0.75 • Z0F — 0.25 •
Forward Threshold:
I
N
3V
0
If Z0R Setting
<
0, Reverse Threshold = 1.25 • Z0R + 0.25 •
I
N
3V
0
If Z0R Setting
≥
0, Reverse Threshold = 0.75 • Z0R + 0.25 •
Reverse Threshold:
Note: 1
∠
Z0MTA = One Ohm at the Zero-Sequence Line Angle
Direction Element Characteristics
R0
X0
Forward Threshold
Reverse Threshold
Z0 PLANE
w
R32N
F32N
Forward
Reverse
"S" listed in
setting ORDER
50NF
Enable
Forward
Threshold
32NE
Reverse
Threshold
50NR
Re[3V
0
•(I
N
•1
∠
Z0MTA)*]
|I
N
|
2
Z0 =
I
N
3V
0
Relay
Word
Bits
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bit
"Forward"
Outputs
q
"Reverse"
Outputs
q
Содержание SEL-351A
Страница 10: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 16: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 34: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 126: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 184: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 198: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 228: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 278: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 384: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 410: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 450: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 454: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 472: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 504: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 558: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 562: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 586: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 608: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...
Страница 666: ...This page intentionally left blank Courtesy of NationalSwitchgear com ...