Out Of 3 Logic; Phase Overcurrent (67/50,67/51); Figure 2.3-1 Phase Overcurrent; Table 2.2-5 2 Out Of 3 Logic Test - Siemens 7PG2113 Technical Manual

2.2.1

2 out of 3 logic

Ensure that at least 1 Phase Overcurrent element is set to Directional. Apply balanced nominal voltage. Apply
current at a level above the 50/51 setting on phase A only at the characteristic angle for forward operation,
normally 45º lagging. Ensure no Directional Phase Overcurrent element operation occurs. Note that non-
directional Phase Overcurrent and Non-direction Earth Fault elements may operate unless disabled.
Repeat the test with Phase A current as above but also with equal current in the B phase at 180º to that in the A
phase.
1 phase current
No 50/51-n Operation
2.3

Phase Overcurrent (67/50,67/51)

Voltage Inputs:
Current Inputs:
Disable:
Map Pickup LED:
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. It should be particularly noted that if the function is enabled, the 51C Cold Load
settings may modify the normal 50-n and 51-n settings if the CB is open during testing.
©2010 Siemens Protection Devices Limited
2 phase current
50/51-n operation
Table 2.2-5 2 out of 3 Logic Test

Figure 2.3-1 Phase Overcurrent

V (V ), V (V ), V (V ) for directional elements.
L1 A L2 B L3 C
I (I ), I (I ), I (I ),
L1 A L2 B L3 C
51V, 51C, 46, 49, 50CBF, 79
51-n/50-n - Self Reset
7PG2113/4/5/6 Commissioning & Maintenance
Chapter 6 Page 24 of 77