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.
Below the principle time sequence of signaling at current reversal is shown.
Protection
Function
Protection
Function
Tele-
Protection
Equipment
Tele-
Protection
Equipment
Tele-
communication
System
CS from the
protection
function,
operating and
reset time
CS initiation to
the
communication
system, operating
and reset time
CS propagation,
propagation
CR selection and
decision,
operating and
reset time
CR to the
protection
function,
operating and
reset time
Time
Fault
occurs
Protection
pick-up
CS initiation
CR to
teleprot.
eq.
CR to
prot.
func
Fault current
reversal
Sending
protection
reset
CS to
communication
drop
CR
reception
drop
CR to
prot.
func
drop
Minimum setting of tDelay
en05000536.vsd
IEC05000536 V1 EN
Figure 299: 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 3V0PU.
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 (3V
0
) 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.
Section 3 1MRK504116-UUS C
IED application
734
Application manual
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