![background image](http://html.mh-extra.com/html/abb/relion-615-series/relion-615-series_technical-manual_2395449.webp)
present, they cause the sum admittance phasor to behave as in case of an ungrounded
network, where directional phasors point in fully opposite directions in the faulty and
healthy feeder.
The direction of the 67YN function is defined with setting
Directional mode
as “Forward”
or “Reverse”. The operation characteristic is defined by tilted operation sector as
illustrated in
. The characteristic provides universal applicability, that is, it is
valid both in compensated and ungrounded networks, also if the compensation coil is
temporarily switched off. The tilt of the operation sector is defined with setting
Tilt angle
to compensate the measurement errors of residual current and voltage transformers. The
typical setting value of 5 degrees is recommended, but it should always reflect the actual
maximum expected measurement errors.
In case of ungrounded network operation, adequate tilt angle must be
allowed to ensure dependable operation of 67YN.
, phasors 1...4 demonstrate the behavior of the directional phasor in different
network fault conditions.
•
Phasor 1 depicts the direction of accumulated sum admittance phasor in case of
ground fault outside the protected feeder (assuming that the admittance of the
protected feeder is dominantly capacitive). The result is valid regardless of the fault
type (low ohmic, high(er) ohmic, permanent, intermittent or restriking). In case
harmonic components are present in the fault quantities, they would turn the phasor
align to the negative
Im(
)
Yo
axis.
•
Phasor 2 depicts the direction of accumulated sum admittance phasor in case of
ground fault inside the protected feeder when the network is ungrounded. The result
is also valid in compensated networks when there are harmonic components present
in the fault quantities (typically low ohmic permanent or intermittent or restriking
fault). In this case, the result is valid regardless of network’s actual compensation
degree. Harmonics would turn the phasor align to the positive
Im(
)
Yo
axis.
•
Phasors 3 and 4 depict the direction of accumulated sum admittance phasor in case of
higher-ohmic ground fault in the protected feeder without harmonics in the fault
quantities when the network is compensated. As no harmonic components are
present, the phase angle of the accumulated phasor is determined by the
compensation degree of the network. With high degree of overcompensation, the
phasor turns towards the negative
Im(
)
Yo
axis (as phasor 4).
1MAC059074-MB A
Section 4
Protection functions
615 series ANSI
443
Technical Manual
Содержание Relion 615 series
Страница 1: ... RELION PROTECTION AND CONTROL 615 series ANSI Technical Manual ...
Страница 2: ......
Страница 39: ...Section 17 Glossary 1181 Table of contents 615 series ANSI 33 Technical Manual ...
Страница 40: ...34 ...
Страница 64: ...58 ...
Страница 210: ...3 19 4 Settings Section 3 1MAC059074 MB A Basic functions 204 615 series ANSI Technical Manual ...
Страница 216: ...210 ...
Страница 884: ...878 ...
Страница 1038: ...1032 ...
Страница 1136: ...1130 ...
Страница 1172: ...1166 ...
Страница 1180: ...1174 ...
Страница 1186: ...1180 ...
Страница 1192: ...1186 ...
Страница 1193: ...1187 ...
Страница 1194: ......
Страница 1195: ......