Advertisement
Z aa =Z bb =Z cc and Z ab =Z bc =Z ca ), then symmetrical setting is applicable. If the impedance
unbalances cannot be ignored, the user shall set a compensation factor (section (i)-4) or use a
matrix setting (section (ii)).The following equations are used to acquire the zero-sequence and
positive-sequence impedances.
Z
Z
0
where,
Z 1 :
Z 0 :
Z aa ,Z bb ,Z cc :
Z ab ,Z bc ,Z ca :
Selection of symmetrical setting mode
Prior to setting, the user should set the scheme switch [FL_ImpSet] to Symmetrical.
Setting zero-sequence impedance
With regard to the zero-sequence-impedance (Z 0GH ), the user should set the value of
resistance for setting [FL_R0] and the value of reactance for setting [FL_X0]. (See
Figure 2.26-1)
Setting positive-sequence impedance
With regard to the positive-sequence-impedance (Z 1GH ), the user should set the value
of resistance for setting [FL_R1] and the value of reactance for setting [FL_X1]. (See
Figure 2.26-1)
Setting compensation factors
Set 100% for the settings when the impedance unbalances can be ignored in each of
phases. If the self- and mutual-impedances are unbalanced, then the user should adjust
the FL results using compensation factors expressed using Equations (2.26-12) to
(2.26-17) below. The user can set the values of the compensation factors using settings
[FL_Kab] to [FL_Kc] in the symmetrical setting mode.
Z
+ Z
+ Z
− ( Z
aa
bb
cc
=
1
+ 2 ( Z
Z
+ Z
+ Z
aa
bb
cc
=
Positive-sequence series-impedance
Zero-sequence series-impedance
Self-impedances for each phase conductor
Mutual-impedances between phases
- 299 -
+Z
+ Z
)
ab
bc
ca
3
)
+ Z
+ Z
ab
bc
ca
3
6F2T0207 (0.01)
(2.26-10)
(2.26-11)
GRE200 (5,6)
Advertisement
