Seg MRD1-T, Руководство пользователя

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TB MRD1-T 10.01 E 13
4.2 Analogue measured value detection
4.2.1 Current measuring
For measuring the relevant currents there is a separate
transducer for each of the existing measured quantities.
This transducer provides galvanical isolation to the re-
lay electronics. Adjustment to transformer vector group
and to the main CT rated currents is realized via the
software. The input signal is transmitted by internal CTs
up to 64 times rated current linear. To achieve an ut-
most accuracy there are two current measuring ranges,
changeover of which is automatically.
Each channel has its own sample-and-hold circuit. All
channels are scanned simultaneously.
4.3 Digital signal processor
The digital signal processor (DSP) in the MRD1 is
mainly used for processing measured values by con-
trolling and monitoring data entry from the different
measuring channels. In addition all input signals are
digitally Fourier filtered. Among other values this proc-
essor calculates RMS values and analyzes harmonics
by processing sampled data and stores digitalized
signal sequences to the memory. Apart from data
management and processing the DSP keeps perform-
ing wide-ranging self-tests.
4.4 Digital main processor
The main processors is the highest control element
within the
MRD1 and processes the actual protection
program which interprets data obtained by the DSP
and so refers to the operational status of the object to
be protected and to the own device. Special protec-
tion mechanism enable the
MRD1 to detect problems
in the own hardware. All communication between
MRD1 and the outside world is also controlled by the
main processor. This does not only mean control of in-
dications or handling of key inputs but also harmoniz-
ing the different data interfaces as well as control of
output relays.