Single-Phase-to-Ground Fault Protection on Valve Side of Hybrid Modular Multilevel Converters Based on Thyristor-Branch-Loop

doi:10.16183/j.cnki.jsjtu.2024.381

Abstract

Abstract:

In high voltage direct current (HVDC) systems based on modular multilevel converters (MMCs), single phase to ground (SPG) fault on the MMC valve side may lead to serious consequences such as overvoltage damage to the submodules of MMC bridge arms, and affect system reliability. Therefore, this paper analyzes the characteristics of SPG faults on the valve side of traditional hybrid MMC based HVDC systems, and proposes a hybrid MMC topology based on a thyristor-branch-loop for value-side SPG fault protection of the HVDC system. In the proposed topology, each arm consists of full bridge and half bridge submodules, while the thyristor branch connects the three-phase lower-arm inductors to form a loop. In the case of SPG fault, the proposed hybrid MMC can suppress the lower-arm current, clamp the alternating current voltage on the MMC valve side, and interrupt the MMC fault current through the thyristor-branch-loop and blocking submodules. The proposed topology features low overvoltage, short current self-shutdown time, fewer full bridge submodules, and low power consumption. The effectiveness of the proposed topology and control strategy is verified by PSCAD/EMTDC simulation and experiments.

Key words: high voltage direct current (HVDC) system, modular multilevel converter (MMC), single phase to ground (SPG) fault on the valve side, thyristor-branch-loop

CLC Number:

TM721

LIN Jinjiao, ZHU Zijian, ZHENG Junchao, TAO Yan, DENG Fujin. Single-Phase-to-Ground Fault Protection on Valve Side of Hybrid Modular Multilevel Converters Based on Thyristor-Branch-Loop[J]. Journal of Shanghai Jiao Tong University, 2026, 60(7): 1141-1150.

Figures/Tables 20

Fig.1

Fig.2

Tab.1

Tab.2

Fig.3

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

Tab.3

Fig.9

Fig.10

Fig.11

Fig.12

Fig.13

Fig.14

Tab.4

Fig.15

Fig.16

References 18

[1]	SHAHANE R, RAO K N, SHUKLA A. A review on hybrid modular multilevel converters for medium voltage applications[C]// 2022 IEEE Energy Conversion Congress and Exposition. Detroit, USA: IEEE, 2022: 1-8.
[2]	史明明, 刘瑞煌, 张宸宇, 等. 考虑输电网与柔性互联配电网交互影响的可靠性评估方法[J]. 电力工程技术, 2024, 43(4): 77-87.
	SHI Mingming, LIU Ruihuang, ZHANG Chenyu, et al. Analytical evaluation method of reliability considering interaction between transmission network and flexible interconnected distribution network[J]. Electric Power Engineering Technology, 2024, 43(4): 77-87.
[3]	赵文强, 侍乔明, 王永平, 等. MMC桥臂电抗器穿墙套管故障特性及保护策略[J]. 电力工程技术, 2022, 41(4): 205-212.
	ZHAO Wenqiang, SHI Qiaoming, WANG Yongping, et al. Fault characteristics and protection stra-tegy of MMC bridge arm reactor wall bushing[J]. Electric Power Engineering Technology, 2022, 41(4): 205-212.
[4]	曾冠铭, 范春菊, 乔林岳, 等. 柔性直流配电网换流站交流母线故障响应特性[J]. 电力系统及其自动化学报, 2019, 31(1): 132-141.
	ZENG Guanming, FAN Chunju, QIAO Linyue, et al. Response characteristics of AC bus fault in converter station of VSC-based DC distribution network[J]. Proceedings of the CSU-EPSA, 2019, 31(1): 132-141.
[5]	张晓宇, 郑超, 莫品豪, 等. 换流变压器阀侧接地故障分析及保护优化[J]. 电力工程技术, 2021, 40(3): 172-178.
	ZHANG Xiaoyu, ZHENG Chao, MO Pinhao, et al. Analysis and protection optimization of grounded fault in valve side of converter transformer[J]. Electric Power Engineering Technology, 2021, 40(3): 172-178.
[6]	LIU W, LI G, LIANG J, et al. Protection of single-phase fault at the transformer valve side of FB-MMC-based bipolar HVdc systems[J]. IEEE Transactions on Industrial Electronics, 2020, 67(10): 8416-8427. doi: 10.1109/TIE.41 URL
[7]	LI G, LIANG J, MA F, et al. Analysis of single-phase-to-ground faults at the valve-side of HB-MMCs in HVDC systems[J]. IEEE Transactions on Industrial Electronics, 2019, 66(3): 2444-2453. doi: 10.1109/TIE.2018.2829666 URL
[8]	LI G, LIU W, JOSEPH T, et al. Double-thyristor-based protection for valve-side single-phase-to-ground faults in HB-MMC-based bipolar HVDC systems[J]. IEEE Transactions on Industrial Electronics, 2020, 67(7): 5810-5815. doi: 10.1109/TIE.41 URL
[9]	NAMI A, LIANG J Q, DIJKHUIZEN F, et al. Analysis of modular multilevel converters with DC short circuit fault blocking capability in bipolar HVDC transmission systems[C]// 2015 17th European Conference on Power Electronics & Applications. Geneva, Switzerland: IEEE, 2015: 1-10.
[10]	LI G, LIANG J, MA F, et al. Analysis of single-phase-to-ground faults at the valve-side of HB-MMCs in bipolar HVDC systems[C]// 2017 IEEE Energy Conversion Congress & Exposition. Cincinnati, USA: IEEE, 2017: 2659-2665.
[11]	LI G, LIANG J, UGALDE-LOO C E, et al. Protection for submodule overvoltage caused by converter valve-side single-phase-to-ground faults in FB-MMC based bipolar HVDC systems[J]. IEEE Transactions on Power Delivery, 2020, 35(6): 2641-2650. doi: 10.1109/TPWRD.61 URL
[12]	XUE S M, GU C, LIU B B, et al. Analysis and protection scheme of station internal AC grounding faults in a bipolar MMC-HVDC system[J]. IEEE Access, 2020, 8: 26536-26548. doi: 10.1109/Access.6287639 URL
[13]	LIU C K, DENG F J, HENG Q, et al. Crossing thyristor branches-based hybrid modular multilevel converters for DC line faults[J]. IEEE Transactions on Industrial Electronics, 2021, 68(10): 9719-9730. doi: 10.1109/TIE.2020.3026277 URL
[14]	郭春义, 李佳硕, 李春华. 基于晶闸管的模块化组合式直流泄能装置及其协调控制策略[J]. 中国电机工程学报, 2024, 44(10): 3836-3849.
	GUO Chunyi, LI Jiashuo, LI Chunhua. Modular combination type dynamic braking resistor based on thyristors and its coordinated control strategy[J]. Proceedings of the CSEE, 2024, 44(10): 3836-3849.
[15]	梁桢, 王勇, 白海滨, 等. 集成直流故障换流电路的改进型混合MMC[J]. 电气传动, 2024, 54(1): 53-60.
	LIANG Zhen, WANG Yong, BAI Haibin, et al. Improved hybrid MMC integrated with DC fault commutated circuit[J]. Electric Drive, 2024, 54(1): 53-60.
[16]	WANG Q S, DENG F J, LIU C K, et al. Thyristor-based modular multilevel converter-HVDC systems with current interruption capability[J]. IET Power Electronics, 2019, 12(12): 3056-3067. doi: 10.1049/pel2.v12.12 URL
[17]	LIU X X, LI G, ZHENG T, et al. Thyristor-pair-and damping-submodule-based protection against valve-side single-phase-to-ground faults in MMC-MTDC systems[J]. IEEE Transactions on Power Delive-ry, 2022, 37(4): 3257-3269.
[18]	赖逸洋, 王增平, 王彤. 电流差动保护在柔直接入的交流电网中适应性分析及改进措施研究[J]. 电力系统保护与控制, 2023, 51(3): 145-154.
	LAI Yiyang, WANG Zengping, WANG Tong. Adaptability analysis of current differential protection in an AC power grid with an MMC-HVDC and improvement measures[J]. Power System Protection & Control, 2023, 51(3): 145-154.

运行模式	T₁	T₂	运行状态	桥臂电流	输出电压
H1	导通	关断	投入	i_arm>0	u_cH
				i_arm<0	u_cH
H2	关断	导通	旁路	i_arm>0	0
				i_arm<0	0
H3	关断	关断	闭锁	i_arm>0	u_cH
				i_arm<0	0

运行模式	T₁	T₂	T₃	T₄	运行状态	桥臂电流	输出电压
F1	导通	关断	关断	导通	投入	i_arm>0	u_cF
						i_arm<0	u_cF
F2	关断	导通	关断	导通	旁路	i_arm>0	0
						i_arm<0	0
F3	关断	关断	关断	关断	闭锁	i_arm>0	u_cF
						i_arm<0	-u_cF

参数	取值
额定功率/MW	660
V_dc/kV	400
交流阀侧线电压/kV	183
X-M	120
M	80
M/X	0.4
子模块电容容值/mF	18
L_s/mH	40
变压器漏感(p.u.)	0.2
交流短路比	8

参数	取值
额定功率/W	80
V_dc/V	40
交流阀侧线电压/V	17.6
X	4
M	1
子模块电容额定值/mF	2.3
L_s/mH	5
交流侧电感/mH	5
R_d/Ω	20