ABB Relion 670 Series Applications Manual page 452

Section 16
Scheme communication
scheme to operate when the line fault blocks the signal transmission. Set the
ms.
16.4.3 Setting guidelines
The parameters for the scheme communication logic for residual overcurrent protection
function are set via the local HMI or PCM600.
The following settings can be done for the scheme communication logic for residual
overcurrent protection function:
Operation : Off or On .
SchemeType : This parameter can be set to Off , Intertrip , Permissive UR , Permissive OR or
Blocking .
tCoord : Delay time for trip from ECPSCH function. For Permissive under/overreaching
schemes, this timer shall be set to at least 20 ms plus maximum reset time of the
communication channel as a security margin. For Blocking scheme, the setting should be >
maximum signal transmission time +10 ms.
Unblock : Select Off if unblocking scheme with no alarm for loss of guard is used. Set to Restart
if unblocking scheme with alarm for loss of guard is used.
tSendMin : Time duration, the carrier send signal is prolonged.
tSecurity : The absence of CRG signal for a time duration of tSecurity is considered as CR
signal.
16.5 Current reversal and weak-end infeed logic for residual
overcurrent protection ECRWPSCH
16.5.1 Identification
Function description
Current reversal and weak-end
infeed logic for residual overcurrent
protection
16.5.2 Application
16.5.2.1 Fault current reversal logic
Figure 229
reversal.
Assume that fault is near the B1 breaker. B1 Relay sees the fault in Zone1 and A1 relay identifies
the fault in Zone2.
Note that the fault current is reversed in line L2 after the breaker B1 opening.
It can cause an unselective trip on line L2 if the current reversal logic does not block the
permissive overreaching scheme in the IED at B2.
446
and figure 230 show a typical system condition, which can result in a fault current
© Copyright 2017 Hitachi Power Grids. All rights reserved
IEC 61850 IEC 60617
identification identification
ECRWPSCH -
1MRK 511 401-UEN Rev. K
tSecurity to 35
ANSI/IEEE C37.2
device number
85
Bay control REC670
Application manual
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