Technical data
Siemens SIP · 2008
12 Motor Protection / 7SK80
12
12/10
Application
Fig. 12/7 Function diagram
The SIPROTEC Compact 7SK80 unit is a
numerical protection relay that can perform
control and monitoring functions and
therefore provide the user with a cost-effec
-
tive platform for asset protection, monitor
-
ing and management, that ensures reliable
supply of electrical power to the motors or
other plant assets. The ergonomic design
makes control easy from the relay front
panel. A large, easy-to-read display was a
key design factor.
Control
The integrated control function permits
control of motors, contactors, disconnect
devices, grounding switches or circuit-
breakers through the integrated operator
panel, binary inputs, DIGSI 4 or the control
or SCADA/automation system (e.g. SICAM,
SIMATIC or other vendors automation sys
-
tem). A full range of command processing
functions is provided.
Programmable logic
The integrated logic characteristics (CFC)
allow the user to add own functions for
automation of switchgear (e.g. interlock
-
ing) or switching sequence. The user can
also generate user-defined messages. This
functionality can form the base to create
extremely flexible transfer schemes.
Line protection
The 7SK80 units can be used for line pro-
tection of high and medium-voltage net
-
works with grounded, low-resistance
grounded, isolated or a compensated
neutral point.
Motor protection
The 7SK80 relay is specifically designed
to protect induction-type asynchronous
motors.
Transformer protection
The relay provides all the functions for
backup protection for transformer differ
-
ential protection. The inrush suppression
effectively prevents unwanted trips that
can be caused by inrush currents.
Backup protection
The 7SK80 can be used as a stand alone
feeder protection relay or as a backup to
other protection relays in more complex
applications.
Metering values
Extensive measured values (e.g. I, V),
metered values (e.g. W
p
, W
q
) and limit
values (e.g. for voltage, frequency) provide
improved system management.
Reporting
The storage of event logs, trip logs, fault
records and statistics documents are stored
in the relay to provide the user or operator
all the key data required to operate modern
substations.
Switchgear cubicles for
high/medium voltage
All units are designed specifically to meet
the requirements of high/medium-voltage
applications.
In general, no separate measuring instru
-
ments (e.g. for current, voltage, frequency,
…) or additional control components are
necessary.
Typically the relay provides all required
measurements, thus negating the use of
additional metering devices like amp, volt
or frequency meters. No additional control
switches are required either. The relay pro
-
vides 9 function keys that can be config
-
ured to replace push buttons and select
switches.