Two-Phase Overcurrent Protection (Only Non-Directional) - Siemens SIPROTEC 4 Manual

Functions
2.2 Overcurrent Protection 50, 51, 50N, 51N
Table 2-4
Internal indication
50-3 A PU
50-2 A PU
50-1 A PU
51 A PU
50-3 B PU
50-2 B PU
50-1 B PU
51 B PU
50-3 C PU
50-2 C PU
50-1 C PU
51 C PU
50N-3 PU
50N-2 PU
50N-1 PU
51N PU
50-3 A PU
50-3 B PU
50-3 C PU
50N-3 PU
50-2 A PU
50-2 B PU
50-2 C PU
50N-2 PU
50-1 A PU
50-1 B PU
50-1 C PU
50N-1 PU
51 A PU
51 B PU
51 C PU
51N PU
(All pickups)
In the trip signals, the element which initiated the tripping is also indicated.
2.2.9

Two-phase Overcurrent Protection (Only Non-Directional)

The 2-phase overcurrent protection functionality is used in isolated or grounded systems where interaction
with existing 2-phase protection equipment is required. As an isolated or grounded system remains opera-
tional with a 1-phase ground fault, this protection serves to detect double ground faults with high ground
fault currents. The respective feeder must be switched off only in this case. A 2-phase measurement is suffi-
cient for this purpose. In order to ensure selectivity of the protection in this section of the system, only phases
A and C are monitored.
If 250 50/51 2-ph prot (settable in P.System Data 1) is set to ON, Ι
ison. If the fault is a simple ground fault in B, the element will not pick up. A double ground fault is assumed
only after pickup on A or C, causing the element to pick up and trip after the delay time has elapsed.
70
Pickup Indications of Overcurrent Protection
Figure
Figure 2-4
Figure 2-6
Figure 2-10
Figure 2-4
Figure 2-6
Figure 2-10
Figure 2-4
Figure 2-6
Figure 2-10
Figure 2-5
Figure 2-8
Figure 2-11
Figure 2-4
Figure 2-4
Figure 2-4
Figure 2-5
Figure 2-6
Figure 2-6
Figure 2-6
Figure 2-5
Figure 2-10
Figure 2-10
Figure 2-10
Figure 2-11
Output indication
50/51 Ph A PU
50/51 Ph B PU
50/51 Ph C PU
50N/51NPickedup
50-3 picked up
50N-3 picked up
50-2 picked up
50N-2 picked up
50-1 picked up
50N-1 picked up
51 picked up
51N picked up
50(N)/51(N) PU
is not used for threshold compar-
B
E50417-G1140-C343-A8, Edition 12.2017
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SIPROTEC 4, 7SJ80, Manual