Method Of Operation; Overall Function; Figure 4.1 Hardware Structure Of The Line Differential Protection 7Sd600 - Siemens SIPROTEC 7SD600 System Manual

Numerical line differential protection SIPROTEC 7SD600 V3.0
4

Method of operation

4.1

Overall function

The numerical line differential protection 7SD600 is
equipped with a powerful 16-bit microprocessor
which enables full digital processing of all tasks, from
the acquisition of measured values through to trip
command initiation to the circuit-breaker.
Figure 4.1 shows the basic structure of the device.
L1 L2 L3 MT
2
1
3
Setting via
control panel
3 binary inputs
(marshallable)
Power supply

Figure 4.1 Hardware structure of the line differential protection 7SD600

Siemens AG January 1999
Ra
Rb
I1 Ia
MI
AI
+ -
E
Y/J N
Method of operation
System manual
In the case of symmetrical nominal current flow, the
summation transformer MT creates a single-phase
equivalent current of 20 mA from the currents coming
from the current transformer. Due to the unbalanced
number of turns of the input windings, with the ratio
of 2 : 1 : 3, each type of fault produces a defined sin
gle-phase AC current which decisively influences the
protection functions of the device.
7SD600
Fault
Operation
mC
4 LEDs
(marshallable)
Isolated serial interface
4
Order no. E50417-G1176-C069-A1
Pilot wire link
with remote end
LCD display
(2x8 characters)
Fail signal
(not marshallable)
2 indications
(marshallable)
2 trip commands
(marshallable)
PC
4 - 1