- 389 -
symmetrical components, as shown in Figure 2.32-2. For further information, see
section 2.32.6(iii).
2
Note: In the calculation of earth fault, user is required to set the R
0
and the X
0
with
settings [FL_1R0] and setting [FL_1X0] respectively, when the impedance of line
GJ is considered in symmetrical components.
3
Note: When the mutual impedance of line GJ is considered , and when parallel lines are
applied, user should set the R
0m
and the X
0m
with settings [FL_1R0m] and
setting [FL_1X0m] respectively,. If a single line is considered, user are not
required to set these settings.
4
Note: User should set the K
a
, K
b
and K
c
with settings [FL_Ka], [FL_Kb], and [FL_Kc],
when the imbalance impedance is considered. For further information, see section
2.32.6(vi).
5
Note: User should set the line length for settings [FL_1line_km] when the length of line
GJ is considered and when the unit of length is represented by kilometer, as
shown in Figure 2.32-2. For further information, see section 2.32.6(v).
Compensation
Consider the influence of the distributed capacitance in Equation (2.32-23), likewise section
2.32.2(i)-2. When the line length is beyond 100km, the result of Equation (2.32-23) requires
compensation. Thus, Equation (2.32-17) is used to find the compensated distance () with
respect to the fault distance () which Equation (2.32-23) calculates. The setting procedures
are discussed later. (See section 2.32.6(iii)-2)
(iii) Data recording trigger and calculation trigger
The calculation is started by signals; and following protection functions provide the trigger
signals:
(a) Distance protection
1
(ZS/ZG)
(b) Over current protection
2
(OC)
(c) Current differential protection (DIFL)
(d) External protection
3
1
Note: For more information of the ZS/ZG, see Chapter
Relay application: Distance
protection
.
2
Note: For more information of the OC, see Chapter
Relay application: Overcurrent
protection
.
3
Note: With regard to the trigger signal from the external protection function, user can
program this trigger signal by using Element IDs (PLC connection points), as
shown in Table 2.32-3, which are also listed in section 0.
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