ABB RELION REX640 - 5.10.2 Function block; 5.10.3 Functionality; 5.10.4 Operation principle

5.10.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Scheme communication logic DSOCPSCH CL 85 21SCHLGC
5.10.2 Function block
Figure 702: Function block
5.10.3 Functionality
The scheme communication logic function DSOCPSCH is used to achieve
instantaneous fault clearing independent of the fault location on the protected
feeder. Several communication scheme types are available.
• Direct underreaching transfer trip DUTT
• Permissive underreaching transfer trip PUTT
• Permissive overreaching transfer trip POTT
• Directional comparison blocking scheme DCB
The directional comparison unblocking scheme DCUB can also be implemented
by complementing the permissive schemes with an additional logic called the
unblocking function, which is also included in DSOCPSCH.
If the permissive overreach scheme is used, some of the power system conditions
require additional special logic circuits, such as the current reversal and weak-end
infeed logic function CRWPSCH.
5.10.4 Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "on" and "off".
The operation of DSOCPSCH can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
1MRS759142 F
Protection related functions
REX640
Technical Manual
1237