Modeling a Hybrid Diode-Thyristor HVDC Rectifier in EMTP-RV

This paper presents the investigation into the viability of a hybrid diode-thyristor high voltage direct current (HVDC) rectifier. The large-scale usage of HVDC transmission is limited by several factors and one of the most important factors is the high cost of conversion equipment. In a traditional HVDC system, a 12-pulse thyristor converter is used. In the proposed hybrid circuit, the lower 6-pulse thyristor bridge (which is connected with a Y-Y transformer), is replaced by a cheaper diode bridge. This reduces the overall capital cost of the 12-pulse rectifier, but has implications regarding the operational behavior of the HVDC terminal and system. The operational behavior of this hybrid diode-thyristor converter under static and dynamic conditions is verified with the simulation package EMTP RV