The final reach in resistive direction for phase-to-ground fault loop measurement
automatically follows the values of the line-positive and zero-sequence resistance, and
at the end of the protected zone is equal to equation
(
)
1
R
2 R1 R0
RFPG
3
=
×
+
+
ANSIEQUATION2303 V1 EN-US
(Equation 230)
2 X1Zx
X0Zx
arctan
2 R1Zx
R0Zx
loop
EQUATION2304 V2 EN-US
(Equation 231)
Setting of the resistive reach for the underreaching zone 1 should follow the condition
to minimize the risk for overreaching:
RFPG
4.5 X1
£
×
ANSIEQUATION2305 V1 EN-US
(Equation 232)
The fault resistance for phase-to-phase faults is normally quite low, compared to the
fault resistance for phase-to-ground faults. To minimize the risk for overreaching, limit
the setting of the zone1 reach in resistive direction for phase-to-phase loop
measurement in the phase domain to:
6
1
RFPPZx
X Zx
IECEQUATION2306 V3 EN-US
(Equation 233)
8.9.3.7
Load impedance limitation, without load encroachment function
GUID-A7CDE76A-D5B5-4641-9324-2E9A99071DF5 v1
The following instructions are valid when Phase selection with load enchroachment,
quadrilateral characteristic function FRPSPDIS (21) is not activated. To deactivate the
function, the setting of the load resistance
RLdFwd
and
RLdRev
in FRPSPDIS (21)
must be set to max value (3000). If FRPSPDIS (21) is to be used for all or some of the
measuring zones, the load limitation for those zones according to this chapter can be
omitted. Check the maximum permissible resistive reach for any zone to ensure that
there is a sufficient setting margin between the boundary and the minimum load
impedance. The minimum load impedance (Ω/phase) is calculated as:
Section 8
1MRK 504 163-UUS A
Impedance protection
342
Transformer protection RET670 2.2 ANSI
Application manual
Содержание RELION RET670
Страница 1: ...RELION 670 SERIES Transformer protection RET670 Version 2 2 ANSI Application manual ...
Страница 2: ......
Страница 48: ...42 ...
Страница 64: ...58 ...
Страница 74: ...68 ...
Страница 104: ...98 ...
Страница 194: ...188 ...
Страница 518: ...512 ...
Страница 618: ...612 ...
Страница 648: ...642 ...
Страница 666: ...660 ...
Страница 672: ...666 ...
Страница 682: ...676 ...
Страница 844: ...838 ...
Страница 868: ...862 ...
Страница 956: ...950 ...
Страница 964: ...958 ...
Страница 1004: ...998 ...
Страница 1014: ...1008 ...
Страница 1015: ...1009 ...