86
Distance protection Chapter 11
Verifying settings by secondary
injection
5.1.1 Measuring the operate limit of set values in cases without shaped load
encroachment characteristics (OperationLdCmp=off)
Procedure for phase to phase fault L1–L2.
1. Subject the IED to healthy normal load conditions for at least two
seconds.
2. Apply the fault condition and slowly decrease the measured imped-
ance to find the operating value of the phase-to-phase loop for zone
1 according to test point 1 in figure 26
and table 15. Compare the re-
sult of the measurement with the set value.
3. Repeat steps 1 to 2 to find the operating value for test point P2, P3 in
table table 15
and the operating value for the phase-to-earth loop ac-
cording to test point P1, P2, P3 in table table 16
.
Observe that the zone that is not tested has to be blocked and the zone that
is tested has to be released.
The procedure for phase to earth faults in L3 is the same as that described
for phase to phase faults except that figure 27
and table 16 should be re-
ferred to.
5.1.2 Measuring the operate time of distance protection zones
Procedure
1. Subject the IED to healthy normal load conditions for at least two
seconds.
11 X 0.27 x (2 x X1
set
+X0
set
) Exact: 0.8 x (2 x X1
set
+ X0
set
)/3
R –0.57 x (2 x X1
set
+ X0
set
) Exact: 0.8 x (2X1
set
+ X0
set
)/(3 x tan(AngNegDir
90))
12 X 0.5 x (2 x X1
set
+ X0
set
)/3
R 0.5 x (2 x R1
set
+ R0
set
)/3
13 X 0
R RFPE
Test point Reach Value Comments
Note!
Test points 8 and 9 are intended to test the directional lines of impedance protection. Since di-
rectionality is a common function for all 5 measuring zones, it is only necessary to test points 6,
7, 8 and 9 once, in the forward direction (the largest reverse zone can be used to facilitate the
test) in order to test the accuracy of directionality (directional angles). Directional functionality
testing (trip inside, no-trip outside) should always be carried for all ZM zones set with direction-
ality (forward or reverse).
To Next Page
Loading...
