GE D30 Instruction Manual page 611

CHAPTER 9: THEORY OF OPERATION
Assuming the system is homogeneous, d is then a real number. The fault resistance does not have any imaginary part. The
preceding equation solved for the unknown m yields the following fault location algorithm:
where
Im( ) stands for the imaginary part of a complex number
Depending on the fault type, appropriate voltage and current signals are selected from the phase quantities before
applying the preceding equation (the superscripts denote phases, the subscripts denote stations).
For AG faults:
For BG faults:
For CG faults:
For AB and ABG faults:
For BC and BCG faults:
For CA and CAG faults:
where K is the zero sequence compensation factor (for the first six equations)
0
Z is the mutual zero sequence impedance
0M
I = I /3 and I is the ground current of the adjacent line. The I
0M G G
line.
For ABC faults, all three AB, BC, and CA loops are analyzed and the final result is selected based upon consistency of the
results.
The element calculates the distance to the fault (with m in miles or kilometers) and the phases involved in the fault.
The relay allows locating faults from delta-connected VTs. If the
and the VTs are connected in wye, the fault location is performed based on the actual phase to ground voltages. If the VTs
are connected in delta, fault location is suspended.
D30 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
compensation term is applied for the entirely parallel
0M
FAULT REPORT 1 VT SUBSTITUTION
FAULT LOCATOR
Eq. 9-13
Eq. 9-14
Eq. 9-15
Eq. 9-16
Eq. 9-17
Eq. 9-18
Eq. 9-19
setting is set to "None,"
9-23
9