Phase Overcurrent (67/50,67/51); Figure 2-2 Phase Overcurrent - Siemens 7SR21 Manual

2.2

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.
Voltage inputs may not be required for this function if the Phase Overcurrent functions are not directional but it
may be advantageous to apply balanced 3 phase nominal rated voltage to the VT inputs during testing to avoid
inadvertent operation of other functions. Particular care should be taken when testing overcurrent functions that
the thermal rating of the current inputs is not exceeded.
©2010 Siemens Protection Devices Limited
7SR21 & 7SR22 Argus Commissioning and Maintenance

Figure 2-2 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
Chapter 6 Page 16 of 69