An Improved Average Value Model for Simulating the Blocking State of HVDC-Flexible Transmission System

At present, the average model can be used to simulate the external electrical characteristics of HVDC-flexible transmission system, the computational complexity does not change with the number of sub modules. However, the existing average model can not reflect the blocking characteristics of converter, so that the starting process and DC fault process can not be accurately simulated. A improved average model of HVDC-flexible transmission system is proposed, which can effectively simulate the relevant waveform after converter locking. The tests show that the proposed improved average model can make up for the shortcomings of the existing average model in simulating converter lockout and DC fault, and improve its effectiveness in simulating the operating conditions of HVDC-flexible transmission system.