![Schweitzer Engineering Laboratories SEL-421-4 Скачать руководство пользователя страница 470](http://html.mh-extra.com/html/schweitzer-engineering-laboratories/sel-421-4/sel-421-4_instruction-manual_1216726470.webp)
6.134
SEL-421 Relay
Instruction Manual
Date Code 20171021
Protection Applications Examples
Out-of-Step Logic Application Examples
Equation 6.83
Angle Ang_R6 was specified at 120.0° as a design criterion for this application
example (see
Zone 6 and Zone 7 Impedance Settings on page 6.121
).
Equation 6.84
Apply a fast unstable swing frequency and calculate OSTD (for this application
example,
slip
= 10 Hz for an unstable power swing).
Equation 6.85
The OSTD timer settings are in increments of 0.125 cycle; round up to the near-
est valid relay setting.
OSTD :=
0.875
.
Out-of-Step Trip Delay (0.500–8000 cycles)
To find the effective slip rate for OOS tripping, solve
for f
slip
:
Equation 6.86
where:
Z
T
= transfer impedance
Z1
S
= positive-sequence source impedance
Z1
L1
= positive-sequence impedance for Line 1
Z1
R
= Positive-sequence remote impedance
where:
NOM
= nominal power system frequency (Hz)
slip
= maximum slip frequency (Hz)
Z
T
Z
1S
Z
1L1
Z
1R
+
+
=
Ang_R7
2
Z
T
2
---------
R1R7
---------------
atan
•
=
2
8.80
88
8.00
87.6
3.52
88
+
+
2
-----------------------------------------------------------------------------------------------------------------
15.53
-----------------------------------------------------------------------------------------------------------------
atan
•
=
66.4
=
OSTD
Ang_R6 Ang_R7
–
f
NOM
•
360
cycle
------------
f
slip
•
---------------------------------------------------------------------------
=
120.0
66.4
–
60 Hz
•
360
cycle
------------
10 Hz
•
--------------------------------------------------------------
=
0.89 cycles
=
f
slip
Ang_R6 Ang_R7
–
f
NOM
•
360
cycle
------------
OSTD
•
---------------------------------------------------------------------------
=
120
66.4
–
60 Hz
•
360
cycle
------------
0.875
•
---------------------------------------------------------
=
10.2 Hz
=
Содержание SEL-421-4
Страница 6: ...This page intentionally left blank ...
Страница 14: ...This page intentionally left blank ...
Страница 30: ...This page intentionally left blank ...
Страница 104: ...This page intentionally left blank ...
Страница 128: ...This page intentionally left blank ...
Страница 536: ...This page intentionally left blank ...
Страница 584: ...This page intentionally left blank ...
Страница 616: ...This page intentionally left blank ...
Страница 696: ...This page intentionally left blank ...
Страница 750: ...This page intentionally left blank ...
Страница 755: ...Instruction Manual PM400 01 NB SEL 400 Series Relays Instruction Manual 20171006 ...
Страница 776: ...This page intentionally left blank ...
Страница 932: ...This page intentionally left blank ...
Страница 976: ...This page intentionally left blank ...
Страница 1024: ...This page intentionally left blank ...
Страница 1038: ...This page intentionally left blank ...
Страница 1064: ...This page intentionally left blank ...
Страница 1128: ...This page intentionally left blank ...
Страница 1206: ...This page intentionally left blank ...
Страница 1316: ...This page intentionally left blank ...
Страница 1350: ...This page intentionally left blank ...
Страница 1464: ...This page intentionally left blank ...
Страница 1468: ...This page intentionally left blank ...
Страница 1492: ...This page intentionally left blank ...
Страница 1518: ...This page intentionally left blank ...