X
ArgDir
IA
ArgNegRes
Z
ANSI09000123-2-en.vsd
f
VA
ZRev
R
ANSI09000123 V2 EN
Figure 48:
Simplified characteristic for offset mho in reverse direction for A-to-
ground fault
6.1.6.5
Minimum operating current
The operation of Five zone distance protection, quadrilateral and mho characteristic
(ZQMPDIS, 21) is blocked if the magnitude of input currents fall below certain threshold
values.
The phase-to-ground loop AG (BG or CG) is blocked if IA (IB or IC) <
IMinOpPG
.
IA (IB or IC) is the RMS value of the current in phase IA (IB or IC). .
The phase-to-phase loop AB (BC or CA) is blocked if I
AB (BC or CA)
<
IMinOpPP
.
The current limits
IMinOpPG
and
IMInOpPP
are automatically reduced
to 75% of regular set values if the zone is set to operate in reverse
direction, that is,
DirModeZx
=
Reverse
(where x is 1-5 depending on
selected zone).
6.1.6.6
Measuring principles
Fault loop equations use the complex values of voltage, current, and changes in the
current. Apparent impedances are calculated and compared with the set limits. The
Section 6
1MRK 506 335-UUS A
Impedance protection
120
Technical manual
Содержание REL650 series
Страница 1: ...Relion 650 series Line distance protection REL650 ANSI Technical manual ...
Страница 2: ......
Страница 42: ...36 ...
Страница 48: ...42 ...
Страница 58: ...52 ...
Страница 68: ...62 ...
Страница 74: ...68 ...
Страница 194: ...188 ...
Страница 534: ...528 ...
Страница 580: ...574 ...
Страница 722: ...716 ...
Страница 792: ...786 ...
Страница 855: ...849 ...