Overall Operation
The numerical, multi-functional protection device SIPROTEC 7SJ61 is equipped with a powerful microproc-
essor. It allows all tasks to be processed digitally, from the acquisition of measured quantities to sending
commands to circuit breakers. Figure 1-1 shows the basic structure of the device.
Analog Inputs
The measuring inputs (MI) convert the currents coming from the instrument transformers and adapt them to
the level appropriate for the internal processing of the device. The device has 4 current inputs. three of these
are for the input of the phase currents. Depending on the model, the fourth current input (Ι
N
) may be used for
measuring the ground fault current Ι
N
(current transformer starpoint) or for a separate ground current trans-
former (for ground fault detection Ι
Ns
). The analog input quantities are passed on to the input amplifiers (IA).
[hw-struktur-7sj61-020702-kn, 1, en_US]
Figure 1-1
Hardware structure of the numerical multi-functional device 7SJ61
The input amplifier IA stage provides a high-resistance termination for the input quantities. It consists of filters
that are optimized for measured-value processing with regard to bandwidth and processing speed.
The analog-to-digital (AD) element consists of a multiplexor, an analog-to-digital (A/D) converter and of
memory components for the transmission of digital signals to the microcomputer system.
Microcomputer System
Apart from processing the measured values, the microcomputer system (μC) also executes the actual protec-
tion and control functions. They especially include:
1.1
Introduction
1.1 Overall Operation
18 SIPROTEC 4, 7SJ61, Manual
C53000-G1140-C210-6, Edition 05.2016
To Next Page
Loading...
Need help?
General