Siemens SIPROTEC 4 7UT6 Series Manual page 26

Introduction
1.3 Characteristics
Commissioning, Operation
•
Isolation of one side or measuring point for maintenance work: the isolated line or measuring point is
withdrawn from the differential protection system processing, without affecting the remainder of the
protection system
•
Comprehensive support facilities for operation and commissioning
•
Indication of all measured values, amplitudes and phase relation
•
Indication of the calculated differential and restraint currents
•
Integrated help tools can be visualised by means of a standard browser: Phasor diagrams of all currents of
all sides and measuring locations of the protected object are displayed as a graph
•
Connection and direction checks as well as interface check
Monitoring Functions
•
Availability of the device is greatly increased because of self-monitoring of the internal measurement
circuits, power supply, hardware, and software
•
Supervision of the current transformer secondary circuits of symmetry and phase sequence
•
Monitoring of the voltage transformer circuits (if voltage inputs are available) for symmetry, voltage sum
and phase rotation
•
Supervision of the voltage transformer circuits (if voltage inputs are available) for voltage failure with fast
function blocking that measure undervoltages
•
Checking the consistency of protection settings regarding the protected object and possible assignment
of the current inputs: Blocking of the differential protection system in case of inconsistent settings which
could lead to a malfunction
•
Trip circuit supervision is possible
•
Broken wire supervision for the secondary CT circuits with fast phase segregated blocking of the differen-
tial protection functions and the unbalanced load protection in order to avoid spurious tripping
Further Functions
•
Battery-buffered real-time clock, which may be synchronised via a synchronisation signal (e.g. DCF77,
IRIG B via satellite receiver), binary input or system interface
•
Continuous calculation and display of operational measured values on the front of the device; indication
of measured quantities of all sides of the protected object
•
Fault event memory (trip log) for the last 8 network faults (faults in the power system), with real-time
assignment
•
Recording of event and fault data for the last 8 system faults (fault in a network) with real-time informa-
tion as well as instantaneous values for fault recording for a maximum time range of 20 s
•
Switching Statistics: Recording of the trip commands issued by the device, as well as recording of the
fault current data and accumulation of the interrupted fault currents
•
Communication with central control and data storage equipment possible via serial interfaces (depending
on the individual ordering variant) by means of data cable, modem or optical fibres Various transmission
protocols are provided for this purpose.
26 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016