Toshiba GR200 Series Instruction Manual page 424

Table 2.32-6 Method and setting in earth fault compensation
Compensation
Switch
method
[FL-Z0B]
Residual-current
Off
Impedance
On
looking in reverse
Note: The user should set Off for the scheme switch [FL-Z0B] when the FL function
operates on a single circuit line.
Setting of the unit of length/distance
(v)
As shown in Figure 2.32-7, the fault determination is shown in kilometer when user sets km
for the scheme switch [FL_Unit]. On the other hand, if the fault determiantion in the mile is
preferred, user should set mile for the scheme switch [FL_Unit]. The IED screen for the FL
computaion are subject to this setting. After that, user can set values for the corresponding
settings.
For example, when we consider the Line1_Element setting, if user selects km for the
scheme switch [FL_Unit], setting [FL_1Line_km] is used to set the line length value. On the
other hand, if user selects mile for the scheme switch [FL_Unit], setting [FL_1Line_mile] is
used to set the line length value.
Setting of compensation factor
(vi)
As discussed in section 2.32.5(v), if the impedance imbalances are found, user should set
the compensation factors for settings [FL_Kab], [FL_Kbc], [FL_Kca], [FL_Ka], [FL_Kb], and
[FL_Kc]. In order to find how to obtain these factors, see section 2.32.5(v).
Computation for overreaching
(vii)
If the user wishes to obtain the result of the FL computation when the fault occurs beyond the
boundary defined with the setting [FL_Line_km] or [FL_Line_mile], the result can be displayed
when On is set for setting [FL_ALL_Zone]. Note that the fault location will be displayed by On
being set for the [FL_ALL_Zone], but the result for overreaching cannot be guaranteed in the
FL computation; thereby, it must be taken carefully.
Setting objects
Impedance
setting
[FL_R0m] 1. The residual current is available in
and the parallel line.
[FL_X0m] 2. The single line is considered.
[FL_Z0B_L],
1. The residual current is not
[FL_Z0B_R],
available in the parallel line.
[FL_R0m],
2. The compensation method above is
and
not preferred.
[FL_X0m]
- 401 -
Decision of compensation method
6F2S1914 (0.49)
Required power
quantities for
this operation
I 0m , I a , I b , I c ,
V a , V b , V c
I a , I b , I c , V a , V b ,
V c
GRL200 (Soft 033 & 037)