Yechun Xin¹, Xinyuan Zhao¹, Dong Ding², Shuyu Chen², Chuanjie Wang², Tuo Wang^1,*

Energy Engineering, Vol.123, No.1, 2026, DOI:10.32604/ee.2025.069748 - 27 December 2025

Abstract To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current (HVDC) links and multi-infeed DC systems in load-center regions, this paper proposes a hybrid modular multilevel converter–capacitor-commutated line-commutated converter (MMC-CLCC) HVDC transmission system and its corresponding control strategy. First, the system topology is constructed, and a submodule configuration method for the MMC—combining full-bridge submodules (FBSMs) and half-bridge submodules (HBSMs)—is proposed to enable direct power flow reversal. Second, a hierarchical control strategy is introduced, including MMC voltage control, CLCC current control, and a coordination mechanism, along with the derivation of… More >

Chunyan Li¹, Luo Li¹, Yushuang Li², Yong Jia¹, Wenyan Li^3,*

Energy Engineering, Vol.122, No.10, pp. 4313-4330, 2025, DOI:10.32604/ee.2025.070187 - 30 September 2025

Abstract To accelerate the large-scale integration of renewable energy and support the strategic goals of “carbon peaking and carbon neutrality,” High Voltage Direct Current (HVDC) transmission technology has made significant breakthroughs. Among the various approaches, a hybrid DC transmission system that combines a line-commutated converter (LCC) and a voltage source converter (VSC) retains the inherent fault self-clearing capability of the LCC topology while mitigating the risk of commutation failure when connected to a weak grid. In this paper, based on the harmonic generation mechanisms of hybrid DC transmission systems, an improved 3-pulse harmonic source model of… More >

Chuanjian Wu, Dahai Zhang^*, Jinghan He

Energy Engineering, Vol.120, No.2, pp. 299-316, 2023, DOI:10.32604/ee.2023.023532 - 29 November 2022

Abstract The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid. Line-commutated converter-Voltage source converter (LCC-VSC) power grids are one of the more important developmental directions of the future power grid that have occured in recent years. But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics, inconsistent control, and fault response characteristics, which puts higher requirements on the protection scheme. Thus, a completely new protection principle is proposed in this paper. Firstly, the fault characteristics of… More >

Dahai Zhang^*, Chuanjian Wu, Jinghan He

Energy Engineering, Vol.120, No.1, pp. 1-21, 2023, DOI:10.32604/ee.2022.023304 - 27 October 2022

Abstract Line-commutated converter-voltage source converter (LCC-VSC) power transmission technology does not have the problem of communication failure very usually. It therefore can support the long-distance, long-capacity transmission of electric energy. However, factors such as topology, control strategy, and short-circuit capacities make the traditional protection principles not fully applicable to LCC-VSC hybrid transmission systems. To enhance the reliability of hybrid DC systems, a single-ended principle based on transmission coefficients is proposed and produced. First, the equivalent circuit of the LCC-VSC hybrid DC system is analyzed and the expression of the first traveling wave is deduced accordingly. Then, More >