Overview
The “Current reversal and weak-end infeed logic for phase segregated communication (ZC1WPSCH)” function is used to prevent unwanted operations due to current reversal when using permissive overreach protection schemes in application with parallel lines where the overreach from the two ends overlaps on the parallel line.
For more detailed information on “Current reversal and weak-end infeed logic for phase segregated communication (ZC1WPSCH)” function, refer to ABB, Relion 670 Series manuals.
To see other supported functions, click here.
Function Identification
Function description | IEC 61850 identification |
IEC 60617 identification |
ANSI/IEEE C37.2 device number |
Current reversal and weak-end infeed logic for phase segregated communication | ZC1WPSCH | – | 85 |
Signals & Setting Parameters
ZC1WPSCH function block

ZC1WPSCH Input signals
ZC1WPSCH Input signals | |||
Name | Type | Default | Description |
U3P | GROUP SIGNAL | – | Voltage |
BLOCK | BOOLEAN | 0 | Block of function |
BLKZ | BOOLEAN | 0 | Block of trip from WEI logic by the fuse-failure function |
CBOPEN | BOOLEAN | 0 | Block of trip from WEI logic by an open breaker |
CRL1 | BOOLEAN | 0 | Carrier receive for WEI logic in Phase L1 |
CRL2 | BOOLEAN | 0 | Carrier receive for WEI logic in Phase L2 |
CRL3 | BOOLEAN | 0 | Carrier receive for WEI logic in Phase L3 |
IRVL1 | BOOLEAN | 0 | Activation of current reversal logic in Phase L1 |
IRVL2 | BOOLEAN | 0 | Activation of current reversal logic in Phase L2 |
IRVL3 | BOOLEAN | 0 | Activation of current reversal logic in phase L3 |
IRVBLKL1 | BOOLEAN | 0 | Block of current reversal function in Phase L1 |
IRVBLKL2 | BOOLEAN | 0 | Block of current reversal function in Phase L2 |
IRVBLKL3 | BOOLEAN | 0 | Block of current reversal function in Phase L3 |
WEIBLK | BOOLEAN | 0 | Block of WEI logic |
WEIBLKL1 | BOOLEAN | 0 | Block of WEI logic in Phase L1 |
WEIBLKL2 | BOOLEAN | 0 | Block of WEI logic in Phase L2 |
WEIBLKL3 | BOOLEAN | 0 | Block of WEI logic in Phase L3 |
WEIBLKOP | BOOLEAN | 0 | Block of WEI logic due to operation of other protection |
WEIBLKO1 | BOOLEAN | 0 | Block of WEI logic in Phase L1 due to operation of other protection |
WEIBLKO2 | BOOLEAN | 0 | Block of WEI logic in Phase L2 due to operation of other protections |
WEIBLKO3 | BOOLEAN | 0 | Block of WEI logic in Phase L3 due to operation of other protections |
ZC1WPSCH Output signals
ZC1WPSCH Output signals | |||
Name | Type | Description | |
TRPWEI | BOOLEAN | Trip of WEI logic | |
TRPWEIL1 | BOOLEAN | Trip of WEI logic in Phase L1 | |
TRPWEIL2 | BOOLEAN | Trip of WEI logic in Phase L2 | |
TRPWEIL3 | BOOLEAN | Trip of WEI logic in Phase L3 | |
IRVOP | BOOLEAN | Operation of current reversal logic | |
IRVOPL1 | BOOLEAN | Operation of current reversal logic in Phase L1 | |
IRVOPL2 | BOOLEAN | Operation of current reversal logic in Phase L2 | |
IRVOPL3 | BOOLEAN | Operation of current reversal logic in Phase L3 | |
ECHO | BOOLEAN | Carrier Send by WEI logic | |
ECHOL1 | BOOLEAN | Carrier Send by WEI logic in Phase L1 | |
ECHOL2 | BOOLEAN | Carrier Send by WEI logic in Phase L2 | |
ECHOL3 | BOOLEAN | Carrier Send by WEI logic in Phase L3 | |
ZC1WPSCH Group settings (basic)
ZC1WPSCH Group settings (basic) | |||||
Name | Values (Range) | Unit | Step | Default | Description |
OperCurrRev | Off On |
– | – | Off | Operating mode of Current Reversal Logic |
tPickUpRev | 0.000 – 60.000 | s | 0.001 | 0.020 | Pickup time for current reversal logic |
tDelayRev | 0.000 – 60.000 | s | 0.001 | 0.060 | Time Delay to prevent Carrier send and local trip |
OperationWEI | Off Echo Echo & Trip |
– | – | Off | Operating mode of WEI logic |
UPE< | 10 – 90 | %UB | 1 | 70 | Phase to Earth voltage for detection of fault condition |
UPP< | 10 – 90 | %UB | 1 | 70 | Phase to Phase voltage for detection of fault condition |
tPickUpWEI | 0.000 – 60.000 | s | 0.001 | 0.010 | Coordination time for the WEI logic |
ZC1WPSCH Non group settings (basic)
ZC1WPSCH Non group settings (basic) | |||||
Name | Values (Range) | Unit | Step | Default | Description |
GlobalBaseSel | 1 – 12 | – | 1 | 1 | Selection of one of the Global Base Value groups |
Logics & highlights
Simplified logic diagram for current reversal

Simplified logic for weak-end infeed logic — Echo

Simplified logic diagram for weak-end infeed logic – Echo & Trip

Blocking of echo signal using WEIBLKLx input of ZC1WPSCH

Blocking of echo signal using WEIBLKOx input of ZC1WPSCH
