Coordinated Control Strategy of SLCC Considering the Carrying Capacity of SVF

The self-adaption statcom and line commutation converter (SLCC) utilizes the static var & filter (SVF) to provide dynamic reactive power compensation and harmonic filtering for converter stations, effectively reducing the risk of commutation failure in inverter stations. However, the evaluation of the bearing capacity of the SVF under fault conditions remains unaddressed. In addition, the lack of effective coordination between the SVF and the line commutation converter (LCC) necessitates further improvement in the ability of the SLCC to resist commutation failure. This paper first analyzes the bearing capacity of the SVF, constrained by the maximum operating current of IGBT valves and the maximum voltage of sub-module capacitors. The maximum bearing capacity of the SVF under different fault scenarios is calculated, and an accurate analytical expression for the commutation overlap angle of the SLCC during AC faults is derived. Based on these findings, a control strategy considering the coordinated operation of the SVF and LCC is proposed to fully leverage the bearing capacity of the SVF and enhance the reliability of HVDC transmission system operation. Finally, a simulation model is developed on the PLECS platform based on the Yangzhou-Zhenjiang HVDC project. The results demonstrate that the proposed control strategy effectively reduces the risk of commutation failure induced by AC-side faults.