ABB Relion 650 Series Applications Manual page 100

Section 7
Current protection
DNSPTOC (46) is used in directional comparison protection scheme for the power line protection,
when communication channels to the remote end of this power line are available. In that case, two
negative sequence overcurrent steps are required - one in forward and another in reverse
direction. The OC1 stage is used to detect faults in forward direction and the OC2 stage is used to
detect faults in reverse direction.
However, the following must be noted for such application:
• setting
• setting
• setting
• setting
element, that is, typically 60% of
operation of the directional comparison scheme during current reversal situations
• the start signals PU_OC1 and PU_OC2 from OC1 and OC2 elements is used to send forward
and reverse signals to the remote end of the power line
• the available scheme communications function block within IED is used between the
protection function and the teleprotection communication equipment, in order to insure
proper conditioning of the above two start signals.
94
RCADir and ROADir are applicable for both steps OC1 and OC2
DirMode_OC1 must be set to Forward
DirMode_OC2 must be set to Reverse
PickupCurr_OC2 must be made more sensitive than pickup value of the forward OC1
ActLowVolt1 and ActLowVolt2 should not be set to Memory .
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PickupCurr_OC1 set pickup level in order to insure proper
1MRK 505 287-UUS B
Busbar protection REB650
Application manual