ABB RELION RED670 Series Product Manual page 44

Line differential protection RED670 2.2
Product version: 2.2
To achieve fast fault clearing for all earth faults on the line, the
directional earth fault protection function can be supported
with logic that uses tele-protection channels.
This is why the IEDs have available additions to the scheme
communication logic.
If parallel lines are connected to common busbars at both
terminals, overreaching permissive communication schemes
can trip unselectively due to fault current reversal. This
unwanted tripping affects the healthy line when a fault is
cleared on the other line. This lack of security can result in a
total loss of interconnection between the two buses. To avoid
this type of disturbance, a fault current reversal logic
(transient blocking logic) can be used.
Permissive communication schemes for residual overcurrent
protection can basically operate only when the protection in
the remote IED can detect the fault. The detection requires a
sufficient minimum residual fault current, out from this IED.
The fault current can be too low due to an opened breaker or
high-positive and/or zero-sequence source impedance
behind this IED. To overcome these conditions, weak-end
infeed (WEI) echo logic is used. The weak-end infeed echo is
limited to 200 ms to avoid channel lockup.
Direct transfer trip DTT
Low active power and power factor protection LAPPGAPC
Low active power and power factor protection (LAPPGAPC)
function measures power flow. It can be used for protection
and monitoring of:
• phase wise low active power
• phase wise low power factor
• phase wise reactive power and apparent power as
service values
Following features are available:
• Definite time stage for low active power protection
• Definite time stage for low power factor protection
• Individual enabling of Low active power and Low power
factor functions
• Low active power trip with 2 selection modes '1 out of 3'
and '2 out of 3'
• Phase wise calculated values of apparent power,
reactive power, active power and power factor are
available as service values
• Insensitive to small variations in voltage and current
Compensated over and undervoltage protection COUVGAPC
Compensated over and undervoltage protection
(COUVGAPC) function calculates the remote end voltage of
the transmission line utilizing local measured voltage, current
and with the help of transmission line parameters, that is, line
resistance, reactance, capacitance and local shunt reactor.
For protection of long transmission line for in zone faults,
COUVGAPCcan be incorporated with local criteria within
44
M13928-6 v2
M13928-8 v5
GUID-25A2A94F-09FE-4552-89F8-CF22632A7A0D v2
GUID-229EB419-0903-46FA-9192-BBB35725C841 v2
direct transfer trip logic to ensure tripping of the line only
under abnormal conditions.
Sudden change in current variation SCCVPTOC
Sudden change in current variation (SCCVPTOC) function is a
fast way of finding any abnormality in line currents. When
there is a fault in the system, the current changes faster than
the voltage. SCCVPTOC finds abnormal condition based on
phase-to-phase current variation. The main application is as a
local criterion to increase security when transfer trips are
used.
Carrier receive logic LCCRPTRC
In Direct transfer trip (DTT) scheme, the received CR signal
gives the trip to the circuit breaker after checking certain local
criteria functions in order to increase the security of the
overall tripping functionality. Carrier receive logic
(LCCRPTRC) function gives final trip output of the DTT
scheme.
Features:
• Carrier redundancy to ensure security in DTT scheme
• Blocking function output on CR Channel Error
• Phase wise trip outputs
Negative sequence overvoltage protection LCNSPTOV
Negative sequence components are present in all types of
fault condition. Negative sequence voltage and current get
high values during unsymmetrical faults.
Zero sequence overvoltage protection LCZSPTOV
Zero sequence components are present in all abnormal
conditions involving earth. They can reach considerably high
values during earth faults.
Negative sequence overcurrent protection LCNSPTOC
Negative sequence components are present in all types of
fault condition. They can reach considerably high values
during abnormal operation.
Zero sequence overcurrent protection LCZSPTOC
Zero sequence components are present in all abnormal
conditions involving earth. They have a considerably high
value during earth faults.
Three phase overcurrent LCP3PTOC
Three phase overcurrent (LCP3PTOC) is designed for
overcurrent conditions.
Features:
• Phase wise start and trip signals
• Overcurrent protection
• Phase wise RMS current is available as service values
• Single definite time stage trip function.
1MRK 505 379-BEN C
GUID-413851A9-5EB7-4C48-8F5D-E30E470EFFAF v2
GUID-79AB9B9E-9200-44D7-B4EE-57C9E7BB74A9 v2
GUID-C5CBB6A2-780D-4008-98E3-455A404D32CB v2
GUID-4CF3EC6A-D286-4808-929B-C9302418E4ED v2
GUID-C4F99554-88BC-4F11-9EFE-91BCA6ED1261 v2
GUID-F0C38DA1-2F39-46DE-AFFE-F919E6CF4A57 v2
GUID-AC4FF35E-5D86-421E-82C7-93F600E9F453 v2
ABB