en99000054_ansi.vsd
LINE 1
A B
Strong
source
Weak
source
CLOSEDCLOSED
FAULT
ANSI99000054 V1 EN
Figure 378: Initial condition for weak-end infeed
16.7.3 Setting guidelines
The parameters for the current reversal and weak-end infeed logic for residual overcurrent
protection function are set via the local HMI or PCM600.
Common base IED values for primary current (IBase), primary voltage (VBase) and
primary power (SBase) are set in a Global base values for settings function GBASVAL.
GlobalBaseSel: It is used to select a GBASVAL function for reference of base values.
16.7.3.1 Current reversal
The current reversal function is set on or off by setting the parameter CurrRev to Enabled
or Disabled. Time delays shall be set for the timers tPickUpRev and tDelayRev.
tPickUpRev is chosen shorter (<80%) than the breaker opening time, but minimum 20 ms.
tDelayRev is chosen at a minimum to the sum of protection reset time and the
communication reset time. A minimum tDelayRev setting of 40 ms is recommended.
The reset time of the directional residual overcurrent protection (EF4PTOC) is typically
25 ms. If other type of residual overcurrent protection is used in the remote line end, its
reset time should be used.
The signal propagation time is in the range 3 – 10 ms/km for most types of communication
media. In communication networks small additional time delays are added in multiplexers
and repeaters. Theses delays are less than 1 ms per process. It is often stated that the total
propagation time is less than 5 ms.
When a signal picks-up or drops out there is a decision time to be added. This decision time
is highly dependent on the interface between communication and protection used. In many
cases an external interface (teleprotection equipment) is used. This equipment makes a
decision and gives a binary signal to the protection device. In case of analog teleprotection
equipment typical decision time is in the range 10 – 30 ms. For digital teleprotection
equipment this time is in the range 2 – 10 ms.
1MRK 506 369-UUS - Section 16
Scheme communication
Line distance protection REL670 2.2 ANSI 773
Application manual
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