IM30-GLF
Doc. N° MO-0062-ING
Rev.
3
Date
14.02.2005
Copyright 2010 - Microener
Firmware:
2.0X
Pag
9
of
31
2.3.6 - F21/40 - Directional Underimpedance / Loss of excitation
The relay computes the impedance
)
cos(
I
E
Z
Characteristics angle of the impedance
= (0°-330°), step 30°
Setting of impedance
angle
Max sensitivity current
angle
Current components
=
0° R
=
0° (360°)
Forward Resistive
= 330° R+C
=
+30°
Forward Res Forward Capacitive
= 300° R+C
=
+60°
Forward Res Forward Capacitive
= 270° C
=
+90°
Forward Capacitive (Loss of Field)
= 240° C-R
=
+120°
Forward Capa Reverse Resistive
= 210° C-R
=
+150°
Forward Capa Reverse Resistive
= 180° -R
=
+180°
Reverse Resistive
= 150° R-R
=
+210° (-150°)
Forward Ind Reverse Resistive
= 120° L-R
=
+240° (-120°)
Forward Ind Reverse Resistive
=
90° L
=
+270° (-90°)
Forward Inductive
=
60° L+R
=
+300° (-60°)
Forward Ind Forward Resistive
=
30° L+R
=
+330° (-30°)
Forward Ind Forward Resistive
The direction
is that of the axle where the center of the circle is located.
N.B. By definition the relation between current displacement
and impedance displacement
is :
= 360°-
Angles are counted anticlockwise from 0° (real axis = direction of phase-to-neutral voltage E)
through 360°.
For example : the displacement of a totally capacitive current is
= 90°; the angle of a totally
capacitive impedance is
= 270°. (see figure)
Operation zone is that included in the circle having (see figure) :
Center on the axle displaced by
at distance
2
K1
K2
from the origin Diameter = K1
Circle offset :
K2
= (5-50)%Zb, step 1%
Circle diameter :
K1
= (50-300)%Zb, step 1%
Setting
K1
= Dis blocks the function’s operation
Ib
3
Uns
Zb
