Because a three-phase APF system is symmetrical, the system is analyzed with its single-phase circuit .
Caption: Figure 2: Single-phase circuit diagram of LC APF with grid impedance.
Figure 2a shows the equivalent single-phase circuit
for the compensated system.
This single-phase circuit
is able to correct power factor in alternating current power network.
In Brazil, for example, there is a common sense so far that single-phase circuits
for rural grids have been adequate to supply the existing loads in rural areas .
In addition, the device can accommodate 36 single-phase circuits
, 12 three-phase circuits, or any combination in between.
The same technical conditions for a single-phase converter are applied and the calculation of inductances for an n-phase design can be accomplished in the same way as for single-phase circuits
. Taking into account the input current which is subdivided into the different phases, the maximum current variation in the inductances must be based on the maximum DC-current at rated power in the individual phases.
The circuits analysed are single-phase circuits
, but a three-phase converter can be easily obtained by joining three single-phase converters.
The goal was to evaluate meters that cost less than $1,000 for a three-phase circuit or three single-phase circuits
. For this study, three phase meters with data logging capability that cost less than $500 are characterized as "low cost." Units that cost between $500 to $750 are characterized as "medium cost" and units that exceed $750 are characterized as "high cost."