Overall Operation - Siemens siprotec 7SA522 User Manual

Introduction
1.1

Overall Operation

Analog Inputs
I
L1
I
L2
I
L3
I
4
U
L1
U
L2
U
L3
U
4
U
aux
Figure 1-1
1-2
The numerical Distance Protection SIPROTEC
32 Bit microprocessor. This provides fully numerical processing of all functions in the
device, from the acquisition of the measured values up to the output of commands to
the circuit breakers. Figure 1-1 shows the basic configuration of the device.
The measuring inputs MI transform the currents and voltages derived from the instru-
ment transformers and match them to the internal signal levels for processing in the
device. The device has 4 current and 4 voltage inputs. Three current inputs are pro-
vided for measurement of the phase currents, a further measuring input (I
configured to measure the earth current (residual current from the current transformer
star-point), the earth current of a parallel line (for parallel line compensation) or the
star-point current of a power transformer (for earth fault direction determination). A
voltage measuring input is provided for each phase–earth voltage. A further voltage
input (U ) may optionally be used to measure either the displacement voltage (e–n–
4
voltage) or any other voltage U
then routed to the input amplifier group IA.
MI IA
7 8 9
Operator
4 5 6
control panel
1 2 3
(6& (17(5
Binary inputs, programmable
Power supply
Hardware structure of the numerical device 7SA522 (maximum configuration)
(for overvoltage protection). The analogue signals are
X
AD µC
∩
µC
#
.
0 +/-
®
7SA522 is equipped with a powerful
OA
ERROR
RUN
Output Relays
user-
programmable
LEDs
on the front
panel, user-
programmable
Display on
the Front Panel
Front Serial Oper-
ating Interface
Time
Synchronization
Rear Serial
Service Interface
Serial
System Interface
C53000-G1176-C119-2
) may be
4
to
PC
radio
clock
PC/
modem
to
SCADA
7SA522 Manual