ABB Relion 670 Series Applications Manual page 454

Section 16
Scheme communication
16.5.3.1 Current reversal
The current reversal function is set on or off by setting the parameter
Time delays shall be set for the timers
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
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.
If the teleprotection equipment is integrated in the protection IED the decision time can be
slightly reduced.
The principle time sequence of signaling at current reversal is shown.
Protection
Function
CS from the
protection
function, operate
and reset time
Fault Protection
occurs pick-up
IEC05000536 V2 EN-US
Figure 232: Time sequence of signaling at current reversal
16.5.3.2 Weak-end infeed
The weak-end infeed can be set by setting the parameter
Operating zero sequence voltage when parameter
448
tDelayRev setting of 40 ms is recommended.
Tele-
Protection
Equipment
CS initiation to
the
communication
system, operate
and reset time
CR to CR to
teleprot. prot.
Fault current
CS initiation
eq. func
reversal
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tPickUpRev and tDelayRev .
Tele- Tele-
communication Protection
System Equipment
CR selection and
CS propagation,
decision, operate
propagation
and reset time
Sending CR
protection reception
reset drop
CR to
CS to
prot.
communication
func
drop
drop
Minimum setting of tDelay
WEI to Off , Echo or Echo & Trip .
WEI is set to Echo & Trip is set with 3U0>.
1MRK 511 401-UEN Rev. K
M13933-6 v5
CurrRev to On or Off .
Protection
Function
CR to the
protection
function, operate
and reset time
Time
IEC05000536-2-en.vsd
M13933-12 v6
Bay control REC670
Application manual