Application - ABB REC650 Applications Manual

1MRK 511 286-UUS A
10.4.2
Application manual
Function description
Interlocking for 1 1/2 breaker diameter
Interlocking for double CB bay
Interlocking for double CB bay
Interlocking for double CB bay
Interlocking for line bay
Interlocking for transformer bay

Application

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 grounding 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.
Grounding switches are allowed to connect and disconnect grounding of isolated points.
Due to capacitive or inductive coupling there may be some voltage (for example < 40%
of rated voltage) before grounding and some current (for example < 100A) after
grounding 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.
IEC 61850 IEC 60617
identification identification
BH_LINE_B -
DB_BUS_A -
DB_BUS_B -
DB_LINE -
ABC_LINE -
AB_TRAFO -
Section 10
Control
ANSI/IEEE C37.2
device number
3
3
3
3
3
3
225