ABB REF615 Applications Manual page 54

Section 3
REF615 variants
48
A071332 V4 EN
Figure 17: Overcurrent protection
Four overcurrent stages are offered for overcurrent and short-circuit protection. The
instantaneous stage (PHIPTOC1) can be blocked by energizing the binary input 1
(X120:1-2). Two negative sequence overcurrent stages (NPSTOC1 and NPSTOC2)
are offered for phase unbalance protection. The inrush detection block's
(INRPHAR1) output BLK2H caters the possibility to either block the function or
multiply the active settings for any of the shown protection function blocks.
All operate signals are connected to the Master Trip and also to the alarm LEDs. LED
1 is used for overcurrent and LED 4 for negative sequence overcurrent protection
operate indication. LED 4 is also used for phase discontinuity protection operate
indication.
The upstream blocking from the start of the overcurrent second high stage
(PHHPTOC2) is connected to the output SO1 (X110:14-16). This output is used for
sending a blocking signal to the relevant overcurrent protection stage of the IED at
the infeeding bay.
1MRS756378 D
REF615
Application Manual