Operation of the electric main multiphase load balancing unit

The article considers algorithms of operating the multiphase unit for balancing main load based on selection of load phase connection to electric network phases with retaining an original order of load phases interlace. The influence of the operating algorithms on the load asymmetry coefficients of zero and negative sequences at the electrical point is analyzed based on computer modeling the treed three-phase electric main. The results show thresholds and limitations of the given operating algorithms. They reveal that the operating algorithm, which meters the magnitude of currents and voltages, can be used to operate the three-phase unit balancing main load when the magnitude of phase load angles, for instance municipal-domestic service load, is similar. Hardware implementation of the algorithm does not require the phase-locked loop within the unit. However, in case of asymmetry characterized by a significant difference in load angles of some particular phases, the use of this algorithm will lead to incorrect work in some instances. This drawback is rare when the operating algorithm controlling both effective ranges and values of the estimated load angle are used, but its implementation makes the unit more complicated. The paper also presents the flowchart of the balancing load unit implementing the given operating algorithms and based on the ATmega8A microcontroller. The flowchart helps operating a switching module of any power and purpose.