1127 / 2019-05-20 23:49:09

Fast Fault Restoration Control Scheme Under LCC-Side Fault for Hybrid HVDC Transmission Systems

Converter technology,Fast fault restoration,Hybrid hvdc,Lcc hvdc,VSC hvdc

This paper investigates a hybrid HVDC transmission system consists of a line commutated converter (LCC) and a voltage source converter (VSC) . In endeavour to improve system resiliency against network faults, this paper proposes a control scheme that offers fast AC fault-ride through capability for the LCC rectifier. the VSC inverter will perceive the LCC-side fault states by the transmitted DC current, and coordinate its DC voltage to speed up the fault restoration time. After analysising the LCC switching behaviour under various DC voltage level was conducted,a flexible DC voltage coordination control scheme for the VSC is designed to cater for the LCC-side fault restoration. Hybrid HVDC transmission system is established in Matlab-Simulink environment in order to demonstrate the effectiveness of the proposed scheme in reducing the LCC rectifier DC current restoration time. The results show the proposed scheme improves the stability of the hybrid HVDC system operation .