Setting Guidelines - ABB REL650 Applications Manual

Section 12
Scheme communication
12.5.3
12.6
12.6.1
408
To overcome the lower dependability in permissive schemes, an unblocking function can
be used. Use this function at older, less reliable, power line carrier (PLC) communication,
where the signal has to be sent through the primary fault. The unblocking function uses a
guard signal CRG, which must always be present, even when no CR signal is received.
The absence of the CRG signal during the security time is used as a CR signal. This also
enables a permissive scheme to operate when the line fault blocks the signal transmission.
Set the tSecurity to 35 ms.

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: Disabled or Enabled.
SchemeType: This parameter can be set to Off , Intertrip, Permissive UR, Permissive OR
or Blocking.
tCoord: Delay time for trip from ECPSCH (85) 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.
tCoord: Delay time for trip from ECPSCH (85) function. For Permissive under/
overreaching schemes, this timer can be set to 0. 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.
Current reversal and weak-end infeed logic for residual
overcurrent protection ECRWPSCH (85)
Identification
Function description
Current reversal and weak-end infeed
logic for residual overcurrent protection
IEC 61850 IEC 60617
identification identification
ECRWPSCH -
1MRK 506 334-UUS A
ANSI/IEEE C37.2
device number
85
Application manual