When large-scale new energy in desert-gobi-wasteland is sent out through a HVDC transmission system

it faces challenges such as low short-circuit ratio and weak AC grid at the sending end

and faces the risk of commutation failure at the receiving end. It is urgent to propose a new DC converter technology to support the transmission of new energy. This article focuses on the impact of commutation failure on the HVDC transmission system. Firstly

the interaction characteristics between the sending end and receiving end of large-scale renewable energy DC transmission system are analyzed; it is found that the fault of AC system at the sending end will lead to commutation failure at the receiving end

and the commutation failure at the receiving end will increase the risk of renewable energy off grid. Then

the research progress of commutation failure mitigation technology is reviewed from following three aspects: device improvement

topology improvement

and control optimization. The existing methods are difficult to eliminate the risk of commutation failure fundamentally. Finally

by integrating the hybrid commutated converter (HCC) based on the integrated gate commutated thyristor (IGCT)

a novel ultra-high voltage hybrid DC transmission system architecture is proposed

utilizing modular multilevel converter-hybrid commutated converter. This architecture can support the long-distance

high-reliability transmission of tens of gigawatts of renewable energy without relying on conventional power supply support and can eliminate the risk of commutation failure

while demonstrating superior performance advantages including high power capacity and cost-effectiveness.