protection at the remote line end and in this way prevents the correct operation
of a complete protection scheme.
• A separate direct intertrip channel must be arranged from the remote end when
a trip or accelerated trip is given there. The intertrip receive signal is connect
to input CRL.
• The WEI function shall be set to WEI=Echo&Trip. The WEI function block
will then give phase selection and trip the local breaker.
Avoid using WEI function at both line ends. It shall only be activated at the weak-
end.
13.2.3 Setting guidelines
IP15024-1 v1
M13856-4 v6
The parameters for the current reversal logic and the weak-end infeed logic (WEI)
function are set via the local HMI or PCM600.
Common base IED values for the primary current (IBase), primary voltage (UBase)
and primary power (SBase) are set in global base values for settings function
GBASVAL.
GlobalBaseSel: Selects the global base value group used by the function to define
IBase, UBase and SBase as applicable.
13.2.3.1 Current reversal logic
M13856-6 v7
The forward zone timer must be set longer than the tDelayRev set
value.
Set CurrRev to On to activate the function.
Set tDelayRev timer of the maximum reset time for the communication equipment
that gives the carrier receive (CRL) signal plus 30 ms. A minimum setting of 40 ms
is recommended, typical 60 ms.
A long tDelayRev setting increases security against unwanted tripping, but delays
the fault clearing time in case of a fault from one line that evolves to the other one.
The probability of this type of fault is small. Therefore set tDelayRev with a good
margin.
Set the pick-up delay tPickUpRev to <80% of the minimum sum of breaker operate
time + communication delay time, but with a minimum of 20 ms.
13.2.3.2 Weak-end infeed logic
M13856-10 v8
Set WEI to Echo, to activate the weak-end infeed function with only echo function.
Set WEI to Echo&Trip to obtain echo with trip.
1MRK 505 393-UEN B Section 13
Scheme communication
Line differential protection RED650 2.2 IEC 287
Application manual