ABB RED670 - Phase-To-Earth Faults; Phase-To-Phase Faults

To verify the mho characteristic, at least two points should be tested.
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.
11.4.3.1 Phase-to-phase faults
M14944-292 v8
ZAngPP
ZPP
1
23
Ohm/phase
R
X
IEC07000009-4-en.vsd
50%
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
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,
ST
ART, 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.
11.4.3.2 Phase-to-earth faults
M14944-393 v7
For simplicity, the same test points as for phase-to-phase faults are proposed, but
considering new impedance values.
Section 11 1MRK 505 378-UEN A
Testing functionality by secondary injection
122 Line differential protection RED670 2.2 IEC
Commissioning manual