Weak-End Infeed - ABB REC670 Applications Manual

Section 15
Scheme communication
15.5.3.2
450
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.
Tele-
Protection
Protection
Function
Equipment
CS initiation to
CS from the
the
protection
communication
function, operate
system, operate
and reset time
and reset time
CR to
teleprot.
Fault Protection
CS initiation eq.
occurs pick-up
IEC05000536 V2 EN-US
Figure 198: Time sequence of signaling at current reversal

Weak-end infeed

The weak-end infeed can be set by setting the parameter WEI to Off, Echo or Echo
& Trip. Operating zero sequence voltage when parameter WEI is set to Echo &
Trip is set with 3U0>.
The zero sequence voltage for a fault at the remote line end and appropriate fault
resistance is calculated.
To avoid unwanted trip from the weak-end infeed logic (if spurious signals should
occur), set the operate value of the broken delta voltage level detector (3U0) higher
than the maximum false network frequency residual voltage that can occur during
normal service conditions. The recommended minimum setting is two times the
false zero-sequence voltage during normal service conditions.
Tele-
communication
System
CS propagation,
propagation
Sending CR
protection reception
reset drop
CR to CS to
prot. communication
Fault current
func drop
reversal
Minimum setting of tDelay
1MRK 511 401-UEN A
Tele- Protection
Protection
Function
Equipment
CR to the
CR selection and
protection
decision, operate
function, operate
and reset time
and reset time
CR to
prot.
func
drop
IEC05000536-2-en.vsd
Bay control REC670 2.2 IEC
Application manual
Time
M13933-12 v6