Analysis of Flexible Power Transformer that Supports New Energy System Connecting Power Grid

This paper presents the flexible power transformer (FPT) that consists of the integration of the standard power transformer and the multilevel rectifier- inverter back-to-back cascaded H-bridge (CHB) converter. The proposed technology pairs a fractionally-rated converter with a conventional transformer to offer a grid control solution at a lower cost-point and with higher reliability compared to existing approaches. The technology has been successfully simulated at the new energy system connecting power grid, 3- phase 66 kV, and lends itself to high voltage direct current transmission levels. Basic concepts and key technological aspects, along with simulation are presented for a 66 kV, 3- phase,
$\pm 10\%$
, 1 MVA converter and 66 kV, 3-phase,
$\pm 50\%$
, 5MV A converter. The simulation results show that the technology can stabilize the voltage of the new power system.