currents have been above the set value MinCurr for more than setting tLowCurr, an
overreaching zone will be allowed to trip "instantaneously" during a fault condition
when one or two of the phase currents will become low due to a three-phase trip at
the opposite IED, see figure
230. The current measurement is performed internally
and the internal STILL signal becomes logical one under the described conditions.
The load current in a healthy phase is in this way used to indicate the tripping at the
opposite IED. Note that this function will not operate in case of three-phase faults,
because none of the phase currents will be low when the opposite IED is tripped.
IEC05000158 V1 EN-US
Figure 230: Loss-of-load acceleration - simplified logic diagram
Breaker closing signals can if decided be connected to block the function during
normal closing.
M13819-14 v2
12.4 Scheme communication logic for residual
overcurrent protection ECPSCH
IP14711-1 v2
12.4.1 Identification
M14882-1 v2
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Scheme communication logic for
residual overcurrent protection
ECPSCH - 85
12.4.2 Functionality
M13918-4 v11
To achieve fast fault clearance of earth faults on the part of the line not covered by
the instantaneous step of the residual overcurrent protection, the directional
residual overcurrent protection can be supported with a logic that uses
communication channels.
In the directional scheme, information of the fault current direction must be
transmitted to the other line end. With directional comparison, a short operate time
1MRK 506 382-UEN A Section 12
Scheme communication
Line distance protection REL650 2.2 IEC 449
Technical manual
To Next Page
Loading...
Need help?
General
