PILOT PROTECTION METHOD FOR FLEXIBLE DC GRID BASED ON RECURSIVE MINIMUM ERROR ENTROPY STATE ESTIMATION UNDER SOURCE-GRID COORDINATED CURRENT LIMITING

Zheng Zongsheng; Wu Tianchi; Liao Jianquan; Zeng Weigang; Wang Qianggang; Zhou Niancheng

doi:10.19912/j.0254-0096.tynxb.2025-0661

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Acta Energiae Solaris Sinica ›› 2026, Vol. 47 ›› Issue (9) : 482-492. DOI: 10.19912/j.0254-0096.tynxb.2025-0661

PILOT PROTECTION METHOD FOR FLEXIBLE DC GRID BASED ON RECURSIVE MINIMUM ERROR ENTROPY STATE ESTIMATION UNDER SOURCE-GRID COORDINATED CURRENT LIMITING

Zheng Zongsheng¹, Wu Tianchi¹, Liao Jianquan¹, Zeng Weigang¹, Wang Qianggang², Zhou Niancheng²

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Abstract

To address the issue that current limiting degrades fault characteristics and may cause conventional pilot protection to malfunction, this paper proposes a recursive minimum error entropy pilot protection method based on model matching, which improves algorithm robustness and eliminates the adverse influence from current limiting. This paper firstly analyzes the fault characteristics of metallic return bipolar DC grids with CFC under current limiting conditions and explains the drawbacks of traditional current differential protection. An accurate line equivalent model is then established to derive system measurement equations, which are discretized by “quadratic integration” into algebraic equations. Finally, the recursive minimum error entropy algorithm is introduced to solve the state estimation model: the internal and external faults are identified according to the model matching degree, and a fault pole selection strategy is proposed according to the fault current mode component. The simulation results show that the method can quickly and accurately recognize the internal and external faults and correctly select poles within 2 ms after fault inception, with strong ability against current limiting, transition resistance and noise interference.

Key words

flexible DC power grid / fault current limiting / recursive minimum error entropy / state estimation / pilot protection / fault pole selection

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Zheng Zongsheng, Wu Tianchi, Liao Jianquan, Zeng Weigang, Wang Qianggang, Zhou Niancheng. PILOT PROTECTION METHOD FOR FLEXIBLE DC GRID BASED ON RECURSIVE MINIMUM ERROR ENTROPY STATE ESTIMATION UNDER SOURCE-GRID COORDINATED CURRENT LIMITING[J]. Acta Energiae Solaris Sinica. 2026, 47(9): 482-492 https://doi.org/10.19912/j.0254-0096.tynxb.2025-0661

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