ABB Relion 670 series, Руководство по применению

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• With basically zero current. The circuit is open on one side and has a small extension. The
capacitive current is small (for example, < 5A) and power transformers with inrush current
are not allowed.
• To connect or disconnect a parallel circuit carrying load current. The switching voltage
across the open contacts is thus virtually zero, thanks to the parallel circuit (for example, <
1% of rated voltage). Paralleling of power transformers is not allowed.
Earthing switches are allowed to connect and disconnect earthing of isolated points. Due to
capacitive or inductive coupling there may be some voltage (for example < 40% of rated
voltage) before earthing and some current (for example < 100A) after earthing of a line.
Circuit breakers are usually not interlocked. Closing is only interlocked against running
disconnectors in the same bay, and the bus-coupler opening is interlocked during a busbar
transfer.
The positions of all switching devices in a bay and from some other bays determine the
conditions for operational interlocking. Conditions from other stations are usually not
available. Therefore, a line earthing switch is usually not fully interlocked. The operator must
be convinced that the line is not energized from the other side before closing the earthing
switch. As an option, a voltage indication can be used for interlocking. Take care to avoid a
dangerous
enable condition at the loss of a VT secondary voltage, for example, because of a
blown fuse.
The switch positions used by the operational interlocking logic are obtained from auxiliary
contacts or position sensors. For each end position (open or closed) a true indication is
needed - thus forming a double indication. The apparatus control function continuously checks
its consistency. If neither condition is high (1 or TRUE), the switch may be in an intermediate
position, for example, moving. This dynamic state may continue for some time, which in the
case of disconnectors may be up to 10 seconds. Should both indications stay low for a longer
period, the position indication will be interpreted as
unknown. If both indications stay high,
something is wrong, and the state is again treated as
unknown.
In both cases an alarm is sent to the operator. Indications from position sensors shall be self-
checked and system faults indicated by a fault signal. In the interlocking logic, the signals are
used to avoid dangerous enable or release conditions. When the switching state of a switching
device cannot be determined operation is not permitted.
For switches with an individual operation gear per phase, the evaluation must consider
possible phase discrepancies. This is done with the aid of an
AND-function for all three phases
in each apparatus for both open and close indications. Phase discrepancies will result in an
unknown double indication state.
14.4.1 Configuration guidelines
M13529-4 v4
The following sections describe how the interlocking for a certain switchgear configuration
can be realized in the IED by using standard interlocking modules and their interconnections.
They also describe the configuration settings. The inputs for delivery specific conditions
(Qx_EXy) are set to 1=TRUE if they are not used, except in the following cases:
• QB9_EX2 and QB9_EX4 in modules BH_LINE_A and BH_LINE_B
• QA1_EX3 in module AB_TRAFO
when they are set to 0=FALSE.
14.4.2 Interlocking for line bay ABC_LINE
IP14139-1 v2
1MRK 505 343-UEN B Section 14
Control
561
Application manual