Design of a novel voltage regulating distribution transformer with a power electronic‐assisted booster system

Distribution grid is facing challenges arising from more and more renewable power generation connected to distribution networks. Heavy embedded generation has led to frequent voltage fluctuations in the form of under‐voltage and over‐voltage. Voltage control using traditional voltage regulators are unable to cope with this situation which limits the power output from renewable power generation. A novel design of a main transformer combined with a second booster transformer is proposed which provides frequent voltage regulation no matter under‐voltage or over‐voltage of distribution networks. The modification in the voltage is produced by the second booster transformer which has taps developed through a combination of no‐load mechanical switches and hybrid switch. The hybrid switch consists of a mechanical switch and two bidirectional semiconductor switches. Mechanical switches ensure low steady‐state losses and the power electronic switches are used for arc‐free tap changing. The novel design of the transformer is cost‐effective, efficient, and can regulate voltage quickly and frequently.