Siemens siprotec 7SD5

1 Introduction
32
7SD5 Manual
C53000-G1176-C169-1
Thermal Overload
Protection
• Provides thermal replica of the current heat losses of the protected object
• R.m.s. measurement of all three phase currents
• Adjustable thermal and current-dependent warning stages
User-defined
Functions
• Freely programmable combination of internal and external signals for the imple-
mentation of user-defined logic functions
• All common logic functions
• Time delays and set point interrogation
Commissioning,
Operation,
Maintenance
• Display of magnitude and phase angle of local and remote measured values
• Indication of the calculated differential and restraint currents
• Display of the measured values of the communication link, such as transmission
delay and availability;
• Function logout of a device from the line protection system during maintenance
work at an end of a power line, test mode and commissioning mode supported
Command
Processing
• Switchgear can be switched on and off manually via local control keys, the program-
mable function keys on the front panel, via the system interface (e.g. by SICAM
®
or
LSA), or via the operator interface (using a personal computer and the operating
software DIGSI
®
);
• Feedback on switching states via the circuit breaker auxiliary contacts (for com-
mands with feedback)
• Plausibility monitoring of the circuit breaker position and monitoring of interlocking
conditions for switching operations
Monitoring
Functions
• Increase of the availability of the device by monitoring of the internal measurement
circuits, auxiliary power supply, hardware, and software;
• Current transformer and voltage transformer secondary circuits are monitored
using summation and symmetry check techniques
• Monitoring of communication with statistics showing the availability of transmission
telegrams
• Check of the consistency of protection settings at all line ends: blocking of the dif-
ferential protection system in case of inconsistent settings which could lead to a
malfunction
• Trip circuit supervision possible
• Check of local and remote measured values and comparison of both
• Broken wire supervision for the secondary CT circuits with fast phase segregated
blocking of the line protection system in order to avoid malfunction
• Supervision of measuring voltage failure using "Fuse Failure Monitor"
Ancillary Functions • Battery buffered real-time clock, which may be synchronized via a synchronization
signal (e.g. DCF77, IRIG B, GPS via satellite receiver), binary input or system inter-
face
• Automatic time synchronization between the devices at the ends of the protected
object via the protection data transmission
www . ElectricalPartManuals . com