Circutor Q20711, Руководство пользователя

Страница: 20 / 36

Page
19
8.1.2.- Features of the monitored electrical network
•
Rated voltage: The rated voltage of the power system to be monitored by
the QNA-P/PV analyzer. For a 3-wire configuration the line-to-line voltage
must be set (ex. 400 V~), and for a 4-wire configuration the line-to-neutral
voltage must be set (ex. 230 V~). If a voltage measurement transformer is
used, then the rated voltage to be set must be referred to the secondary
side (ex. 63.5 V~). The correct configuration of this is essential because
the limits for the analysis of the quality of electrical power supply is to be
analysed.
•
Rated frequency: The rated frequency of the power system to be
monitored by the QNA-P/PV analyzer. This parameter is necessary for the
calculation of the RMS signal value in extreme quality networks.
•
4 Wire / 3 Wire: The QNA-P/PV analyzer must be set according to the
distribution system to be monitored, whether with neutral conductor (4
wires) or without neutral conductor (3 wires or Aron). The proper setting of
this point is essential to ensure the correct detection of events. This choice
must also match the external connection configuration.
•
Circuit type: When measurement is via three current probes, then the
analyzer must be set to operate with a three-phase circuit. For 3-wire
networks, that is, networks without neutral conductor, the analyzer can be
set to work in ARON system. Here only two current probes are required.
8.1.3.- Quality parameters
In order to determine electrical power supply quality, the voltage levels
defining the event must be set beforehand.
Therefore, following points must be user-defined:
•
% of voltage swell threshold: The detection of a voltage swell depends on
the value set for this point (% of the rated voltage). Every semi-cycle with a
RMS value over the defined limit value is said to be a voltage swell. A record
will be kept in the events file (EVQ) every time this limit is exceeded, with the
indication of the phase, the maximum voltage value detected, the voltage
average value, voltage value previous to the event and the duration of the
voltage swell event.