Siemens SIPROTEC 7SD80 User Manual

Introduction
1.1 Overall Operation
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
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1.1 Overall Operation
The digital SIPROTEC 7SD80 overcurrent protection is equipped with a powerful microprocessor. 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 7SD80 device.
Analog Inputs
The measuring inputs (MI) convert the currents and voltages coming from the instrument transformers and
adapt them to the level appropriate for the internal processing of the device. The device provides 4 current
transformers and - depending on the model - additionally 3 voltage transformers. Three current inputs serve for
the input of the phase currents, another current input (I
N
) may be used for measuring the ground fault current
I
N
(current transformer starpoint) or for a separate ground current transformer (for sensitive ground fault detec-
tion I
Ns
and directional determination of ground faults) - depending on the model.
Figure 1-1 Hardware structure of the 7SD80 differential protection

Siemens SIPROTEC 7SD80 Specifications

General

Brand	Siemens
Model	SIPROTEC 7SD80
Category	Protection Device
Language	English