Transient stability margin assessment of AC/DC hybrid system with commutation failure involved. (October 2021)

• Record Type: Journal Article
• Authors: Hu, Jiawei; Wang, Tong; Wang, Zengping
• Is Part Of: International journal of electrical power & energy systems. Volume 131(2021)
• Publication Date: 2021-10
• Subjects: AC/DC hybrid system -- Commutation failure -- Energy function -- Transient stability margin assessment; Electrical engineering -- Periodicals; Electric power systems -- Periodicals; Électrotechnique -- Périodiques; Réseaux électriques (Énergie) -- Périodiques; Electric power systems; Electrical engineering; Periodicals; 621.3
• DOI: 10.1016/j.ijepes.2021.107056
• Languages: English
• ISSNs: 0142-0615

Abstract

Highlights: A novel energy function of AC/DC hybrid system is derived, where generators adopt 6th order electromechanical model and DC system adopts electromagnetic model; The energy function based criteria are put forward for the stability assessment of AC/DC hybrid system considering commutation failure, where the error of stability assessment is acceptable. The CCT calculated by proposed approach is faster and more convenient than that of TDS, which will greatly benefit the efficiency of online DSA of AC/DC hybrid system. By comparison, the accuracy of transient stability margin assessment is greatly improved when generators adopt 6th order electromechanical model and DC system adopts electromagnetic model. Abstract: The commutation failure of Line Commutated Converter-High Voltage Direct Current (LCC-HVDC) caused by AC fault has an increasingly serious impact on the transient stability of AC/DC hybrid system. This paper presents a novel transient stability margin assessment approach based on energy function, where generators adopt 6th order electromechanical model and DC system adopts electromagnetic model. First, the network structure-preserving model of AC/DC hybrid system is established, and its energy function is deduced. Next, the energy function of post-fault system is approximately calculated by trapezoidal integral path, and energy function based transient stability criteria are put forward to determine whether the post-fault system is stable or not. Then, Bisection Method (BM) is employed to obtain Critical Clearing Time (CCT) quickly and effectively where CCT can be adopted as index of stability margin. Finally, the New England-39 bus system integrated with LCC-HVDC is used as test system to investigate the effectiveness of the proposed transient stability margin assessment approach.