8.5.3
Setting guidelines
SEMOD154701-1 v1
8.5.3.1
General
SEMOD154704-4 v2
The settings for the Full-scheme distance protection, quadrilateral for earth faults
(ZMMPDIS, 21) function are done in primary values. The instrument transformer ratio
that has been set for the analogue input card is used to automatically convert the
measured secondary input signals to primary values used in ZMMPDIS (21) function.
The following basics should be considered, depending on application, when doing the
setting calculations:
•
Errors introduced by current and voltage instrument transformers, particularly
under transient conditions.
•
Inaccuracies in the line zero-sequence impedance data, and their effect on the
calculated value of the ground-return compensation factor.
•
The effect of infeed between the IED and the fault location, including the
influence of different Z0/Z1 ratios of the various sources.
•
The phase impedance of non transposed lines is not identical for all fault loops.
The difference between the impedances for different phase-to-ground loops can be
as large as 5-10% of the total line impedance.
•
The effect of a load transfer between the IEDs of the protected fault resistance is
considerable, the effect must be recognized.
•
Zero-sequence mutual coupling from parallel lines.
8.5.3.2
Setting of zone1
SEMOD154704-15 v1
The different errors mentioned earlier usually require a limitation of the underreaching
zone (normally zone 1) to 75 - 90% of the protected line.
In case of parallel lines, consider the influence of the mutual coupling according
tosection
"Parallel line application with mutual coupling"
and select the case(s) that are
valid in your application. We recommend to compensate setting for the cases when the
parallel line is in operation, out of service and not grounded and out of service and
grounded in both ends. The setting of grounded fault reach should be selected to be
<95% also when parallel line is out of service and grounded at both ends (worst case).
8.5.3.3
Setting of overreaching zone
SEMOD154704-19 v3
The first overreaching zone (normally zone2) must detect faults on the whole protected
line. Considering the different errors that might influence the measurement in the same
way as for zone1, it is necessary to increase the reach of the overreaching zone to at
least 120% of the protected line. The zone2 reach can be even higher if the fault infeed
Section 8
1MRK 504 163-UUS A
Impedance protection
306
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 ...