PROJECT TITLE :

Application of Transformer-Less UPFC for Interconnecting Two Synchronous AC Grids With Large Phase Difference

ABSTRACT:

In this paper, the application of an innovative transformer-less unified power flow controller (UPFC) for interconnecting 2 synchronous ac grids with giant section distinction is presented. The proposed transformer-less UPFC relies on 2 cascaded multilevel inverters. As is well-known, the real power flow between 2 generators is mainly determined by their section distinction. If 2 grids with massive part difference are initially break away every alternative, once connected, there will be huge current flowing through the transmission line and will, thus, damage the generators or other supplementary equipments. Therefore, to attach 2 synchronous ac grids with every alternative while not using an additional device is impossible. For decades, researchers are investigating completely different approaches to this drawback but still difficult to overcome, especially for real hardware implementation. A good answer using the transformer-less UPFC is demonstrated during this paper. The transformer-less UPFC can understand grid interconnection, independent active and reactive power management, dc-link voltage balance management, etc. Furthermore, a one-pu equipment can compensate system with section difference as large as thirty°. Experimental results based on the 13.8-kV/ two-MVA transformer-less UPFC prototype are shown to validate the theoretical analysis.