Setting Guidelines - ABB REL650 Applications Manual

Section 12
Scheme communication
12.3.3
12.3.3.1
404
current distribution. Here, the fault current increases when the breaker opens in the strong
terminal, and a sequential tripping is achieved. This requires a detection of the fault by an
independent tripping zone 1.
To avoid sequential tripping as described, and when zone 1 is not available, weakend
infeed tripping logic is used. The WEI function sends back (echoes) the received signal
under the condition that no fault has been detected on the weak-end by different fault
detection elements (distance protection in forward and reverse direction).
The WEI function can be extended to trip also the breaker in the weak side. The trip is
achieved when one or more phase voltages are low during an echo function.
Together with the blocking Teleprotection scheme some limitations apply:
• Only the trip part of the function can be used together with the blocking scheme. It is
not possible to use the echo function to send the echo signal to the remote line IED.
The echo signal would block the operation of the distance protection at the remote
line end and in this way prevent the correct operation of a complete protection
scheme.
• A separate direct intertrip channel must be arranged from remote end when a trip or
accelerated trip is given there. The intertrip receive signal is connect to input CRL.
Avoid using WEI function at both line ends. It shall only be activated at the weak end.

Setting guidelines

The parameters for the current reversal logic and the weak-end infeed logic (WEI)
function are set via the local HMI or Protection and Control Manager (PCM600).
Common base IED values for primary current (setting IBase), primary voltage (setting
VBase) and primary power (setting SBase) are set in a Global base values for settings
function GBASVAL. Setting GlobalBaseSel is used to select a GBASVAL function for
reference of base values.
Current reverse logic
CurrRev: Sets CurrRev to Enabled to activate current reversal logic.
tDelayRev: Sets tDelayRev timer at 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 delay the fault
clearing in case of a fault developing from one line to involve the other one. The
probability of this type of fault is small. Therefore set tDelayRev with a good margin.
1MRK 506 334-UUS A
Application manual