Page no.
20
8.1.2.-
Features of the system.
•
Nominal voltage:
This is the nominal voltage measured by the analyzer.
For 3 wire settings the compound voltage must be set (e.g. 400 V), and for
4 wire, the simple voltage (e.g. 230 V). If measurement is done via voltage
transformers, the nominal voltage that is to be set must refer to the
secondary (e.g. 63.5 V). This value is vital to the proper working of event
recording.
•
Nominal frequency:
Nominal frequency of the system being analyzed.
This parameter is necessary for calculating the effective value of the signal
in extreme quality systems.
•
3 wire / 4 wire:
The QNA-412 is designed to operate in installations with
Neutral (4 wire) or installations without Neutral (3 wire). For this, the type of
connection will be defined. This point is very important because it will
measure events depending on how it is set.
•
Type of circuit:
If measurement is being done via three current sockets,
the type of measurement circuit must be set as three phase. The QNA has
the option to measure current with the Aron system in installations that do
not have neutral (3 wire). This means that only two current sockets are
used for the measurements.
8.1.3.-
Quality Parameters.
In order to calculate the supply quality, the voltage levels above which
an event will have deemed to occurred have to be set.
Therefore it is necessary to define the following points
•
% Overvoltage threshold:
Detecting overvoltage will depend on the value
that is set in this section. For every half cycle that its effective value exceeds
this defined value (% above nominal voltage) it will be considered to be
overvoltage. The events file (EVQ) will record each time this value is
exceeded, showing the phase, maximum voltage recorded, average voltage,
voltage prior to the event and the time when this threshold was exceeded.
Overvoltages
Hysteresis
Nominal Voltage
Hysteresis
Dip / Short cut-off
Hysteresis
Interruption / Cut
