- 380 -
(i) Calculation Principle
Calculation on two-terminal application
Figure 2.32-1 shows two IEDs exist at the end of the line GH. Voltages due to the fault are
calculated by Equation (2.32-1) and Equation (2.32-2).
Figure 2.32-1 IED G and IED H on line GH
where,
V
G
: Voltage at IED G
I
G
: Current at IED G
V
H
: Voltage at IED H
I
H
: Current at IED H
Distance ratio of GF to GH
V
f
: Voltage at fault point
Z
GH
1
: Impedance on line GH
Substituting Equation (2.32-1) for Equation (2.32-2)
gives,
The distance ratio () is also calculated with the differential current (Id) because the net
currents at the IED G and the IED H are equal to the differential current (Id= I
G
+I
H
):
1
Note: User should set the Z
GH
into Line1_Element. For further information, see section
2.32.5(ii). For setting methods, see section 2.32.6(iii).
Calculation on three-terminal application
The principle mentioned above is also applicable for the operation of three terminals, as shown
in Figure 2.32-2. Note that one of three calculations (Calc. 1 to 3) determines the fault location.
To Next Page
Loading...
