59
3 zone impedance protection (Z(n)RW)
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In figure 31, the measuring characteristics for two impedance measuring zones (phase-
to-earth fault) in the forward direction are shown. Here the earth impedance measuring
loop, Z
loop
, consists of phase impedance Z
1
, the earth return impedance Z
N
and the re-
sistance R
F
.
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The earth return impedance follows for each particular zone the expression:
with
R
jX
RFPE
1
Z
1
X
1
X
2
Z
N
Z
loop
RFPE
2
R
F
en02000638.vsd
Z
N
1
2
---
z
0
Z
1
–
(
)
⋅
=
Summary of Contents for REO 517
Page 10: ... RQWHQWV ...
Page 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Page 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Page 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Page 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Page 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Page 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Page 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Page 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Page 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...