60
3 zone impedance protection (Z(n)RW)
&KDSWHU
/LQHLPSHGDQFH
and
In case of short lines the possibility of covering sufficiently large fault resistance is im-
portant. The different setting options for the range in the reactive and resistive reach
provide increased flexibility for the distance protection.
An optimized overreaching communication system can increase the resistance coverage
yet further. The optimal solution in some applications is to add the directional earth-
fault function to the distance protection.
In railway applications the margin to the load impedance is, in order to avoid load con-
flicts, of primary significance. Quadrilateral characteristics with different range of set-
tings in the reactive (to cover sufficient length of the line) and resistive (to avoid load
conflicts) directions will, to a large extent, reduce the conflicts that are extremely com-
mon for circular characteristics.
A large reactive setting range, that is independent for each zone, together with current
sensitivity down to 10% of the rated current is an important factor to increase the oper-
ability of the distance protection when used on long lines.
)XQFWLRQDOLW\
Measured current and voltage values are used for the fault loop equations. The apparent
impedances are calculated and checked against the set limits.
The calculation of apparent impedances at faults for single-phase catenary is:
(Equation 15)
where:
RFPE, X and KN
are the reach setting parameters
Z
1
RFPE
1
jX
1
+
=
Z
0
2 K
N
⋅
1
+
(
)
Z
1
⋅
=
Z
ap
U
L1
I
L1
---------
=
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 ...