162
Monitoring Chapter 11
Verifying settings by secondary
injection
Table 22: Test settings
14.3.1 Measuring the operate limit
Procedure
1. Set the test point (|Z| fault impedance and ZΦ impedance phase
angle ) for a condition that meets the requirements in table 22
.
2. Subject the IED to healthy normal load conditions for at least two
seconds.
3. Apply a fault condition.
Check that the distance-to-fault value displayed on the HMI complies
with the following equations (the error should be less than five percent):
in % for two- and three-phase faults
in % for single-phase-to-earth faults
in % for single-phase-to-earth faults with mutual zero sequence current.
Parameter: Condition:
I Higher than 30% I
r
Healthy conditions U = 63,5 V, I = 0 A & ZF = 0°
Impedance |Z| Test point
Note:
•Z
x
≤ (X0 + 2 · X1)/3For single-phase faults
•Z
x
≤ X1 For three and two phase faults
•Z
x
≤ (X0 + 2 · X1 XM)/3For single-phase fault with mutual
zero-sequence current
Impedance angle ZΦ Test angle
•ZΦ arctan[(X0 + 2 · X1) / (R0 + 2R1)] For single-phase faults
•ZΦ arctan(X1/R1)For two-phase faults
Where:
p = the expected value of a distance to fault in percent
Z
x
= set test point on the test set
X0 = set zero-sequence reactance of a line
X1 = set positive-sequence reactance of a line
XM = set mutual zero-sequence impedance of a line
p
Z
x
X1
-------
100⋅=
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