ABB Relion 670 series Product Manual page 17

ABB
Line distance protection REL670 ANSI
Pre-configured
Product version: 1.2
Apparatus control APC
The apparatus control functions are used for control
and supervision of circuit breakers, disconnectors
and grounding switches within a bay. Permission to
operate is given after evaluation of conditions from
other functions such as interlocking, synchronism
check, operator place selection and external or
internal blockings.
Apparatus control features:
• Select-Execute principle to give high reliability
• Selection function to prevent simultaneous
operation
• Selection and supervision of operator place
• Command supervision
• Block/deblock of operation
• Block/deblock of updating of position indications
• Substitution of position indications
• Overriding of interlocking functions
• Overriding of synchrocheck
• Operation counter
• Suppression of Mid position
Two types of command models can be used:
• Direct with normal security
• SBO (Select-Before-Operate) with enhanced
security
In normal security, the command is processed and
the resulting position is not supervised. However
with enhanced security, the command is processed
and the resulting position is supervised.
Normal security means that only the command is
evaluated and the resulting position is not
supervised. Enhanced security means that the
command is evaluated with an additional
supervision of the status value of the control object.
The command security with enhanced security is
always terminated by a CommandTermination
service primitive.
Control operation can be performed from the local
HMI under authority control if so defined.
8. Scheme communication
Scheme communication logic for distance or
overcurrent protection ZCPSCH (85)
To achieve instantaneous fault clearance for all line
faults, a scheme communication logic is provided.
All types of communication schemes for example,
permissive underreaching, permissive overreaching,
blocking, unblocking, intertrip are available.
The built-in communication module (LDCM) can be
used for scheme communication signaling when
included.
Current reversal and weak-end infeed logic for
distance protection ZCRWPSCH (85)
The current reversal function is used to prevent
unwanted operations due to current reversal when
using permissive overreach protection schemes in
application with parallel lines when the overreach
from the two ends overlap on the parallel line.
The weak-end infeed logic is used in cases where
the apparent power behind the protection can be
too low to activate the distance protection function.
When activated, received carrier signal together
with local under voltage criteria and no reverse zone
operation gives an instantaneous trip. The received
signal is also echoed back to accelerate the
sending end.
Three phase or phase segregated scheme logic is
available.
Local acceleration logic ZCLCPLAL
To achieve fast clearing of faults on the whole line,
when no communication channel is available, local
acceleration logic (ZCLCPLAL) can be used. This
logic enables fast fault clearing during certain
conditions, but naturally, it can not fully replace a
communication channel.
The logic can be controlled either by the
autorecloser (zone extension) or by the loss-of-load
current (loss-of-load acceleration).
1MRK 506 317-BUS A
17