
11.4.3.1
Phase-to-phase faults
ZAngPP
ZPP
1
2
3
Ohm/phase
R
X
IEC07000009-4-en.vsd
50%
IEC07000009 V4 EN
Figure 27:
Proposed test points for phase-to-phase fault
Table 22:
Test points for phase-to-phase (ohms / phase)
Test
points
reach
Value
Comments
1
X
ZPP · sin(ZAngPP)
R
ZPP · sin(ZAngPP)
2
X
0,5· (ZPP· sin(ZAngPP)
R
0,5·ZPP + ΔR = 0,5·ZPP·(1+cos(ZAngPP))
3
X
0,5·ZPP·sin(ZAngPP)
R
0,5·ZPP - ΔR = 0,5·ZPP(1-cos(ZAngPP))
Change the magnitude and angle of phase-to-phase voltage to achieve impedances at test
points 1, 2 and 3. For each test point, observe that the output signals, PICKUP, PU_x and
PHPH_FLT are activated where x refers to the actual phase to be tested. After the timer
tPP
for the actual zone has elapsed, also the signals TRIP, TRPP and TR_x shall be
activated.
11.4.3.2
Phase-to-ground faults
For simplicity, the same test points as for phase-to-phase faults are proposed, but
considering new impedance values.
Section 11
1MRK 504 165-UUS -
Testing functionality by secondary injection
122
Transformer protection RET670 2.2 ANSI
Commissioning manual
Summary of Contents for RELION RET670
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