Siemens SIPROTEC 7SD610 Manual page 19

A voltage measuring input is provided for each phase-earth voltage. In principle, the differential protection does
not require any measured voltage, however, for the directed overcurrent time protection, the connection of the
phase earth voltages U
and powers and serve to measure the line voltage also for automatic reclosure can be connected to the device.
A further voltage input (U
or for any other voltage U
input amplifier group.
The input amplifier group IA provides high-resistance termination for the analog input quantities. It consists of
filters that are optimized for measured value processing with regard to bandwidth and processing speed.
The AD analog-to-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 µC also executes the actual protection
and control functions consisting of:
• Filtering and conditioning of the measured signals
• Continuous monitoring of the measured quantities
• Monitoring of the pickup conditions for 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, synchronisation of the differential protection values and
summing up of the overall differential currents and the overall charge
• Monitoring the communication with the device of the remote end
• Monitoring of limit values and time sequences
• Control of signals for logical functions
• Reaching trip and close command decisions
• Recording of messages, fault data and fault values for analysis
• Administration of the operating system and its functions, e.g. data storage, realtime clock, communication,
interfaces, etc.
The information is provided via output amplifier OA.
Binary Inputs and Outputs
Binary inputs from and outputs to the computer system are routed via the I/O modules (inputs and outputs).
The computer system obtains information from the system (e.g remote resetting) or from the external equip-
ment (e.g. blocking commands). Outputs are commands that are issued to the switching devices and messag-
es for remote signalling of important events and states.
Front Elements
LEDs and an LC display provide information on the function of the device and indicate events, states and mea-
sured values.
Integrated control and numeric keys in conjunction with the LCD facilitate local communication with the device.
Thus, all information of the device, e.g. configuration and setting parameters, operating and fault messages,
and measured values can be retrieved or changed (see also chapter 2 and SIPROTEC 4 System Description).
Devices with control functions also allow control of switchgear from the front panel.
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
, U und U is definitely required. Additionally, voltages that allow to display voltages
L1 L2 L3
) may optionally be used to measure either the displacement voltage (e-n voltage),
4
(for overvoltage protection). The analogue values are transferred further to the IA
x
Introduction
1.1 Overall Operation
19