Siemens siprotec 7SD5, Руководство пользователя

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1.1 Overall Operation
21
7SD5 Manual
C53000-G1176-C169-1
and other ancillary functions. A further voltage input (U
4
) may optionally be used to
measure either the displacement voltage, for a busbar voltage (for synchronism and
voltage check) or any other voltage U
X
(for overvoltage protection). The analog signals
are then routed to the input amplifier group “IA”.
The input amplification IA stage provides high-resistance terminations for the analog
input quantities. It contains filters that are optimized with regard to bandwidth and pro-
cessing speed.
The AD analog digital converter group contains analog/digital converters and memory
chips for data transfer to the microcomputer system.
Microcomputer
System Apart from processing the measured values, the microcomputer system also executes
the actual protection and control functions. In particular, the following are included:
• Decisions for trip and close commands,
• Continuous supervision of measured signals.
• Monitoring of the pickup conditions of the individual protection functions.
• Formation of the local differential protection values (phasor analysis and charge
current computation) and creation of the transmission protocol.
• Decoding of the received transmission protocol, synchronization of differential pro-
tection values and summing up of the differential currents and charge currents,
• Monitoring of the communication with the other devices part of the line protection
system
• Interrogation of threshold values and time sequences.
• Processing of signals for the logic functions.
• Decisions for trip and close commands
• Storage of messages, fault annunciations as well as fault records for system fault
analysis
• Operating system and related function management such as, e.g., data recording,
real-time clock, communication, interfaces, etc.
The information is provided via output amplifier OA.
Binary Inputs and
Outputs The microcomputer system obtains external information through binary inputs such as
remote resetting or blocking commands for protection functions. The computer system
obtains the information from the system (e.g remote resetting) or the external equip-
ment (e.g. blocking commands). These outputs include, in particular, trip commands
to circuit breakers and signals for remote annunciation of important events and condi-
tions.
Front Elements Light emitting diodes (LEDs) and a display screen (LCD) on the front panel provide
information such as measured values, messages related to events or faults, status,
and functional status of the device.
Integrated control and numeric keys in conjunction with the LCD facilitate local inter-
action with the device. All information of the device can be accessed using the inte-
grated control and numeric keys. The information includes protective and control set-
tings, operating and fault messages, and measured values (see also Chapter 2 and
SIPROTEC
®
4 System Description /1/).
Using integrated switchgear control functions, the control of circuit breakers and other
equipment is possible from the device front panel.
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