Circutor Computer SMART III FAST 12, Instruction Manual

Page: 22 / 112

The unit can be used to configure programs from 1.1.1.1 to 1.9.9.9.
4�1�5� Plug and Play�
When a reactive energy regulator is installed, a series of parameters must be configured for its correct
operation. Some of these parameters might be difficult to discover, for example, the voltage phases
or the correspondence between measured current and its voltage, as well as the current transformer
ratio. The
Computer SMART III FAST
includes an automatic process, which intelligently works out nec-
essary parameters such as:

Connection type:
detects the connection type used from among the possible options:
3U
.
3C
,
3U
.
1C
and
2U
.
1C
.

Phase:
identifies the correspondence between the voltages and the currents connected, re-
gardless of the connection type detected previously.

Number of stages installed and Program:
sequentially connects all the stages to work out
how many stages are installed and calculates the program, in other words, the power ratio be-
tween the capacitors.

C/K:
calculates the ratio between the current transformer and the power of the smallest step.
4�1�6 Connection time (Ton) and Reconnection time (Trec)�
The
Connection time, Ton
, defines the shortest possible time between changes in the status of the
stages, in other words, between connections and disconnections. Therefore, the configuration of this
parameter has a direct impact on the compensation speed, in other words, on the capacity for moni-
toring load changes. Setting a shorter connection time improves the power factor correction when the
load can change quickly.
However, a shorter
Ton
will lead to a higher number of connections per time unit, possibly shortening
the useful life of the associated components (thyristors, capacitors). To assess the number of connec-
tions, the
Computer Smart III FAST
uses individual energy meters for each stage.
The
Reconnection time, Trec
, is the shortest possible time between disconnecting a stage and recon-
necting it. This time is necessary for the capacitor to discharge enough so that, when it is reconnected,
it does not cause overcurrents in the system.
Both Ton and Trec have different time bases for the Computer SMART III FAST (in seconds) and for the
Computer SMART III FAST
(in network cycles).
4�1�7 THD and harmonics
Non-linear loads, such as those in rectifiers, inverters, variable speed drivers, furnaces, etc., absorb
non-sinusoidal periodic currents from the mains. These currents are made up of a fundamental com-
ponent with a frequency of 50 or 60 Hz, plus a series of overlapping currents with frequencies that are
multiples of the fundamental frequency; these are defined as harmonics. The result is a deformation of
the current and, thus, of the voltage, which leads to a series of related side effects (conductor overload,
circuit breakers and machines, phase unbalances, interferences in electronic units, RCCB trips, etc.).
The level of harmonics is usually measured with the total harmonic distortion rate (THD), which is
the ratio, usually as a %, of the RMS value of the harmonic content and the value of the fundamental
component.
22
Computer SMART III FAST
Instruction Manual