Overall Operation - Siemens 7SC80 Manual

Introduction

1.1 Overall Operation

1.1 Overall Operation
This chapter introduces the SIPROTEC Feeder Protection and Recloser Controller 7SC80 and gives an overview
of the device's application, properties and functions.
Analog Inputs
The measuring inputs (MI) convert the currents and voltages coming from the transformers and adapt them to
the level appropriate for the internal processing of the device.
Depending on the device type, the device features the following connections:
•
4 current transformers for conventional connection, 3 current transformers for small-signal transformers
(LoPo/LPS = Low Power Sensor/Line Post Sensor)
•
1, 4 or 6 voltage transformers
3 current inputs are provided for input of the phase currents, 1 additional input (Ι
ground fault current Ι
The optional voltage transformers can either be used to input three phase-to-ground voltages or for two
phaseto- phase voltages and the displacement voltage (open delta voltage). It is also possible to connect two
phaseto- phase voltages in an open delta connection.
The voltage input Vx which is always available can be used for 1-phase measurements of any voltages. In the
variants with LoPo/LPS current inputs, the voltage transformer Vx can be used as current measuring input Ι
this case, the actual measuring input Ι
The analog input quantities are passed on to the input amplifiers (IA). The input amplifier IA element 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) transformer group consists of an analog-to-digital converter and memory compo-
nents for the transmission of data to the microcomputer.
22
(current transformer neutral point).
N
acts as sensitive ground current measuring input (Ι
A
) can be used to detect the
N
).
Ns
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
. In
A