Improper connections of unbalanced distributed generators (DGs) and loads in a\nthree-phase microgrid cause unbalanced and bidirectional power flow problems. The unbalanced\nDGs and loads may also aggravate the electric power quality (EPQ), such as voltage regulation,\npower factor, and unbalanced current and voltage. This increases the difficulty of operation in\na microgrid. In this study, a three-phase, delta-connected, shunt-type universal compensator\nwas employed for achieving the bidirectional power-flow balancing and improving the EPQ\nof a three-phase, distribution-level microgrid with unbalanced DGs and loads. A feedforward\ncompensation scheme was derived for the compensator by using the symmetrical components\nmethod. In practical applications, the universal compensator can be implemented as static var\ncompensators (SVCs), static synchronous compensators (STATCOMs), or an additional function\nof active filters. With the on-line compensation of the proposed compensator, the bidirectional\npower-flow balancing and EPQ improvement in the microgrid were achieved. A demonstration\nsystem was proposed to present the effectiveness of the compensator.
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