Scheme Communication - ABB Relion 670 Series Product Manual

Bay control REC670
Version 2.2
A criterion based on delta current and delta voltage
measurements can be added to the fuse failure
supervision function in order to detect a three phase
fuse failure, which in practice is more associated with
voltage transformer switching during station
operations.
Fuse failure supervision VDSPVC
Different protection functions within the protection IED
operates on the basis of measured voltage at the relay
point. Some example of protection functions are:
• Distance protection function.
• Undervoltage function.
• Energisation function and voltage check for the weak
infeed logic.
These functions can operate unintentionally, if a fault
occurs in the secondary circuits between voltage
instrument transformers and the IED. These
unintentional operations can be prevented by fuse
failure supervision (VDSPVC).
VDSPVC is designed to detect fuse failures or faults in
voltage measurement circuit, based on phase wise
comparison of voltages of main and pilot fused circuits.
VDSPVC blocking output can be configured to block
functions that need to be blocked in case of faults in the
voltage circuit.
Voltage based delta supervision DELVSPVC
Delta supervision function is used to quickly detect
(sudden) changes in the network. This can, for example,
be used to detect faults in the power system networks
and islanding in grid networks. Voltage based delta
supervision (DELVSPVC) is needed at the grid
interconnection point.
Current based delta supervision DELISPVC
Delta supervision function is used to quickly detect
(sudden) changes in the network. This can, for example,
be used to detect disturbances in the power system
network. Current based delta supervision (DELISPVC)
provides selectivity between load change and the fault.
Present power system has many power electronic
devices or FACTS devices, which injects a large number
of harmonics into the system. The function has
additional features of 2
harmonic start level adaption. The 2
secures the operation during the transformer charging,
when high inrush currents are supplied into the system.
Delta supervision of real input DELSPVC
Delta supervision functions are used to quickly detect
(sudden) changes in the power system. Real input delta
supervision (DELSPVC) function is a general delta
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GUID-6188C4C1-E1D5-421A-B496-96676287EBB2 v2
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nd
harmonic blocking and 3
nd
harmonic blocking
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function. It is used to detect the change measured
qualities over a settable time period, such as:
• Power
• Reactive power
• Temperature
• Frequency
• Power factor

15. Scheme communication

Scheme communication logic with delta based
blocking scheme signal transmit ZCPSCH
To achieve instantaneous fault clearance for all line
faults, scheme communication logic is provided. All
types of communication schemes for permissive
underreaching, permissive overreaching, blocking, delta
based blocking, unblocking and intertrip are available.
The built-in communication module (LDCM) can be used
for scheme communication signaling when included.
Current reversal and weak-end infeed logic for
distance protection ZCRWPSCH
The ZCRWPSCH function provides the current reversal
and weak end infeed logic functions that supplement
the standard scheme communication logic. It is not
suitable for standalone use as it requires inputs from
the distance protection functions and the scheme
communications function included within the terminal.
On detection of a current reversal, the current reversal
logic provides an output to block the sending of the
teleprotection signal to the remote end, and to block
the permissive tripping at the local end. This blocking
condition is maintained long enough to ensure that no
unwanted operation will occur as a result of the current
reversal.
On verification of a weak end infeed condition, the weak
end infeed logic provides an output for sending the
received teleprotection signal back to the remote
sending end and other output(s) for local tripping. For
terminals equipped for single- and two-pole tripping,
outputs for the faulted phase(s) are provided.
Undervoltage detectors are used to detect the faulted
phase(s).
rd
Local acceleration logic ZCLCPSCH
To achieve fast clearing of faults on the whole line, when
no communication channel is available, local
acceleration logic (ZCLCPSCH) can be used. This logic
enables fast fault clearing and re-closing during certain
conditions, but naturally, it can not fully replace a
communication channel.
1MRK 511 404-BEN N
M13860-3 v11
M13896-3 v15
M13823-3 v7
Hitachi Power Grids