Hitachi Relion 670 Series Applications Manual page 295

1MRK506375-UEN Rev. N
IEC99000044 V3 EN-US
Figure 142:
When the breaker on the parallel line operates, the fault current on the healthy line is reversed. The
IED at B2 recognizes the fault in forward direction from reverse direction before breaker operates. As
IED at B2 already received permissive signal from A2 and IED at B2 is now detecting the fault as
forward fault, it will immediately trip breaker at B2. To ensure that tripping at B2 should not occur, the
permissive overreaching function at B2 needs to be blocked by IRVL till the received permissive
signal from A2 is reset.
The IED at A2, where the forward direction element was initially activated, must reset before the
send signal is initiated from B2. The delayed reset of output signal IRVL also ensures the send signal
from IED B2 is held back till the forward direction element is reset in IED A2.
13.4.2.2 Weak-end infeed logic
Figure 143
no fault current from node B. This causes that the IED at B cannot detect the fault and trip the
breaker in B. To cope with this situation, a selectable weak-end infeed logic is provided for the
permissive overreaching scheme.
Strong
source
A
IEC99000054 V3 EN-US
Figure 143:
13.4.3 Setting guidelines
The parameters for the current reversal and weak-end infeed logic for residual overcurrent protection
function are set via the local HMI or PCM600.
Common base IED values for primary current (IBase), primary voltage (UBase) and primary power
(SBase) are set in a Global base values for settings function GBASVAL.
GlobalBaseSel: To select a GBASVAL function for reference of base values.
13.4.3.1 Current reversal
The current reversal function is set on or off by setting the parameter CurrRev to On or Off. Time
delays shall be set for the timers tPickUpRev and tDelayRev.
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 tDelayRev setting of 40 ms is recommended.
Railway application RER670
Application manual
L1
A1
L2
A2
Current distribution for a fault close to B side when breaker at B1 is opened
shows a typical system condition that can result in a missing operation. Note that there is
IEC99000054-3-en.vsd
Initial condition for weak-end infeed
© 2017 - 2023 Hitachi Energy. All rights reserved
B1
B2
IEC99000044-2.vsd
Weak
source
B
Section 13
Scheme communication
M15285-6 v5
IP15042-1 v1
M13933-4 v6
M13933-6 v5
289