PROJECT TITLE :

Simulation study of FACTS devices based on ACÐAC modular multilevel hexagonal chopper - 2017

ABSTRACT:

This study proposes a replacement range of flexible AC transmission system (FACTS) device based on direct AC-AC conversion, where the modular multilevel AC hexagonal chopper (M2AHC) is utilized. The M2AHC is operated in quasi-two-level mode; and the heterodyne modulation is used to decouple voltage amplitude regulation from the section-shift; so, independent control of active and reactive powers is achieved. Then, a family of FACTS devices primarily based on M2AHC that gives voltage, active power and reactive power flow control as each shunt and series compensators is analysed. The use of AC cell capacitors rather than DC capacitors in M2AHC makes its footprint much smaller and lighter than typical AC-DC or DC-AC voltage supply converter-primarily based FACTS devices; hence, high reliability and extended service-life could be expected. The system modelling and controller design of the proposed FACTS devices are illustrated in an exceedingly unified reference frame, considering completely different management modes, transient and unbalanced conditions. Simulation results are used to verify the feasibility of the proposed M2AHC-based mostly FACTS device. These FACTS devices can be most popular over typical counterpart for confined spaced applications like the grid access of large-scale offshore wind farms and determination of loop flow in megacities.