Overall Operation - Siemens Siprotec 7VK61 Manual

Introduction

1.1 Overall Operation

1.1 Overall Operation
The digital breaker management relay SIPROTEC 4 7VK61 is equipped with a powerful microprocessor
system. All tasks are processed fully digitally, from the acquisition of measured values up to sending commands
to the circuit breakers. Figure 1-1 shows the basic structure of the 7VK61.
Analog Inputs
The measuring inputs (MI) transform the currents and voltages from the instrument transformers and match
them to the internal signal levels for processing in the device. The device has 4 current inputs and 4 voltage
inputs. Three current inputs are provided for measuring the phase currents, a further measuring input (I
be configured to detect the earth current (CT starpoint) or a separate earth current transformer. The analog
input quantities are passed on to the input amplifiers (IA).
Figure 1-1
A voltage measuring input is provided for each phase-earth voltage. A further voltage input (U
ed to measure either the displacement voltage, for the additional voltage of synchronism and voltage check or
for any other voltage U
plifier group.
The input amplifier group IA provides high-resistance termination for the analog input quantities. It consists of
filters that are optimized for measured value processing with regard to bandwidth and processing speed.
16
Hardware structure of the Breaker Management Device 7VK61
(for overvoltage protection). The analogue values are transferred to the IA input am-
X
4
SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009
) can
4
) may be select-