Abstract:
This study proposes a hybrid control (HC) strategy for improved frequency regulation and power sharing in multiterminal HVDC (MTDC) integrated AC grids. The proposed method uses the topology of bi-polar converters in the MTDC
system to improve power sharing and frequency regulation. In this methodology, the two voltage source converters (VSCs) in a
bi-polar topology are operated with individual specified control methods. In the proposed HC method, one of the converters
operate in voltage square frequency droop (PV2f) and another in power frequency droop (Pf) control methods. This HC strategy
is implemented for grid side voltage source converters in MTDC grids. Further, the performance of frequency regulation and
autonomous power sharing of the proposed HC technique is compared with the conventional voltage and frequency droop (PVf)
and improved PV2f control methodologies. In order to validate the proposed method, two AC-MTDC systems are considered. In
both the systems, mesh typed MTDC CIGRE B4 DC test system is in common, it is integrated with two-area power system and
New England IEEE 39-bus system to form two different AC-MTDC systems.
