ABB Relion 670 Series Applications Manual page 368

Section 15
Control
In most cases, the same value can be used for both
source function. However,
communication delays, mainly when representing a circuit breaker.
15.3.9.5 Bay Reserve (QCRSV)
The timer
cannot be done by requesting bay due to for example communication failure.
When the parameter
apparatus (x) in the bay, only the own bay is reserved, that is, the output for reservation
request of other bays (RES_BAYS) will not be activated at selection of apparatus x.
15.3.9.6 Reservation input (RESIN)
With the
installed in the SA system.
15.4 Interlocking
The main purpose of switchgear interlocking is:
• To avoid the dangerous or damaging operation of switchgear
• To enforce restrictions on the operation of the substation for other reasons for example,
load configuration. Examples of the latter are to limit the number of parallel transformers
to a maximum of two or to ensure that energizing is always from one side, for example,
the high voltage side of a transformer.
This section only deals with the first point, and only with restrictions caused by switching
devices other than the one to be controlled. This means that switch interlock, because of
device alarms, is not included in this section.
Disconnectors and earthing switches have a limited switching capacity. Disconnectors may
therefore only operate:
• 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
blown fuse.
362
tStartMove may need to be increased to accommodate for the
tCancelRes defines the supervision time for canceling the reservation, when this
ParamRequestx ( x =1-8) is set to Only own bay res. individually for each
FutureUse parameter set to Bay future use the function can handle bays not yet
enable condition at the loss of a VT secondary voltage, for example, because of a
© Copyright 2017 Hitachi Power Grids. All rights reserved
tStartMove and tIntermediate as in the
1MRK 511 401-UEN Rev. K
M16677-3 v4
M16678-3 v4
IP15572-1 v2
M13530-4 v4
Bay control REC670
Application manual