Phase-To-Phase Faults; Phase-To-Earth Faults - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.4.3.1
11.4.3.2
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
In the following, three test points are proposed. The mho characteristic always goes
through the origin, which automatically gives a fourth point for the characteristic.

Phase-to-phase faults

X
3
IEC07000009 V4 EN-US
Figure 27: Proposed test points for phase-to-phase fault
Table 24: Test points for phase-to-phase (ohms / phase)
Test reach Value
points
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,
START, STLx and STPP 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 TRx shall be activated.

Phase-to-earth faults

For simplicity, the same test points as for phase-to-phase faults are proposed, but
considering new impedance values.
1
ZPP
2
50%
ZAngPP
R
IEC07000009-4-en.vsd
Section 11
M14944-292 v8
Ohm/phase
Comments
M14944-393 v7
119