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
earth fault inside the protected feeder when the network is unearthed. 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 earth 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).
Figure 197: Directional characteristic of MFADPSDE
Protection functions
1MRS758755 C
394
REC615 & RER615
Technical Manual
