Table 21: Test points for phase-to-phase loops A-B (Ohm/phase)
Test point Reach Value Comments
1 X X1
R 0
2 X 0
R RLdFwd When RLdFWd < 0,5·RFLdFwPP
R 0.5·RFLdFwPP When RLdFwd > 0,5·RFLdFwPP
3 X 0.85·X1 R=0.491·X1+0.5 RFLdFwdPP
R 0.85·X1·1/tan(60°)+0.5
RFLdFwdPP
4 X 0.85·X1 Can be limited by RFLdFwPP
R -0.85·X1·tan (AngNegRes-90°)
5 X 0.5·RFLdFwdPP·tan (ArgLd) Only when RLdFwd < RFLdFwPP
R 0.5·RFLdFwdPP
6 X -0.5·RLdFwd·tan (ArgDir)
R 0.5·RLdFwd
Table 21 is used together with figure 26.
11.4.2.1 Measuring the operating limit of set values
Procedure:
1. Supply the IED with healthy conditions for at least two seconds.
2. Apply the fault condition and slowly decrease the measured impedance to find the
operate value for of the phase-to-ground loop ECG, test point 1, according to figure
25. Compare the result of the measurement with the expected value according to
table 20.
The corresponding binary signals that inform about the operation of the phase
selection measuring elements are available in the local HMI under
Main menu/Test/Function status/Impedance Protection/PhaseSelection(PDIS,
21)/FDPSPDIS:x.
3. Repeat steps
1 to 2 to find the operate values for the remaining test points according
to figure 25 and table 20.
Section 11 1MRK 504 165-UUS -
Testing functionality by secondary injection
120 Transformer protection RET670 2.2 ANSI
Commissioning manual
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