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Research on the Key Parameters and Device Capacity Decoupling Analysis of Full Bridge MMC DC Ice-Melting Device [PDF]
, 2023 [Introduction] This article aims to study the issue of the melting capacity and reactive output capacity of the full bridge modular multi-level converter (MMC) type DC (Direct Current) melting ice device under different operating modes.
Rui HE, Xiaogang WU
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Capacitor Voltage Ripple and Harmonics Analysis in MMC [PDF]
, 2023 [Introduction] The rapid development of VSC-HVDC provides practical support for MMC (Modular Multi-Level Converter) topology. Takes a half bridge MMC converter as an example, the relationship between steady-state capacitor voltage fluctuation, harmonic ...
Gang LI +4 more
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Research on Startup of DC Transformer for Electric Vehicle Cluster Grid-Connection [PDF]
, 2023 Modular multilevel direct current transformer (MMDCT) provides a feasible solution to realize the efficient and stable integration of electric vehicle charging and discharging cluster into urban DC distribution network.
FAN Weihao +6 more
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, 2023 张北可再生能源柔性直流电网工程投运以来，交直流系统中数次出现次、超同步振荡问题。对2022年某日振荡发生时现场录波采集到的交直流振荡波形数据进行分析，录波数据分析表明，交流侧的次同步（43.75 Hz）、超同步（56.25 Hz）振荡，在dq坐标系下均表现为6.25 Hz振荡，同时在直流电压和直流电流中也出现了6.25 Hz的振荡频率。初步判断振荡发生的原因是：风电场功率快速变化时，站间骤然变化的直流电压引起了直流电流发生振荡，直流电流通过直流通路造成MMC子模块电容电压产生振荡 ...
刘一民 +5 more
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, 2023 针对中国第一个海上风电柔性直流送出工程—江苏如东工程，从系统拓扑方案构建、过电压与绝缘配合、系统功率盈余问题与交流故障穿越技术以及控制保护技术等方面开展了深入研究，构建了轻型紧凑化的海上风电柔性直流系统拓扑方案，取消了海上换流站的启动回路与接地回路等；提出了海陆换流站的避雷器配置方案与参考电压的选取原则，形成了海陆换流站的绝缘配合方案的典型范式；提出了集中式、分布式、混合式直流侧有功功率动态平衡装置的典型拓扑方式，解决了陆上换流站交流侧故障穿越难题；提出了工程的整体控制保护方案 ...
卢亚军 +6 more
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柔性直流并入城市电网后对换流站近区短路电流的影响研究 [PDF]
, 2023 大型城市供电电网短路电流已经接近断路器遮断容量，柔性直流接入系统后，会在故障期间提供工作电流，导致交流系统短路电流超标，柔性直流输送功率受限。从柔性直流内外环控制方式及交流系统短路电流计算原理出发，分析得出柔性直流短路电流的幅值和相位对并网点的短路电流影响均较大，其中幅值受外环电流限幅环节的影响易于控制，因此需着重对相位进行控制。基于此提出了一种降低柔性直流输电换流站两端PCC点短路电流的控制策略。以厦门柔性直流工程为例，开发了交直流混合模型，与实测波形对比验证了模型的正确性。通过对不同类型故障下 ...
寇龙泽, 朱琳, 范征, 谷怀广
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Electricity Transmission Strategy Research Based on Wind-Coal-Battery-Hydrogen-CCUS Multi Energy Coupling and Bundling System [PDF]
, 2023 [Introduction] In order to guarantee urban power supply and offshore wind power utilization without building new power lines, the paper aims to establish a electricity transmission strategy based on wind-coal-battery- hydrogen -CCUS multi energy coupling
Jiamin YIN +7 more
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Application and Prospect of Flexible Transmission and Distribution Technology in Internet Data Center [PDF]
, 2023 [Introduction] As an important thrust of China's "new infrastructure", internet data centers have ushered in opportunities for vigorous development and become new areas of energy use, putting forward higher requirements for the power supply level and ...
Deyang CHEN +7 more
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含直流断路器的双极接线柔性直流输电系统 MMC 交流侧单相接地故障研究 [PDF]
全球能源互联网, 2020 双极接线柔性直流输电系统采用中性母线接地，换流器交流侧对地电压含有直流偏置，换流器交流侧发生单相接地故障特性不同于对称单极接线系统。柔性直流输电系统配置直流断路器时，换流器交流侧接地故障后可利用直流断路器的直流电流分断能力快速隔离故障。针对含直流断路器的双极接线柔性直流输电系统，分析了模块化多电平换流器（modular multilevel converter, MMC）交流侧单相接地故障机理，阐述了MMC保护闭锁前后故障相和非故障相上、下桥臂的故障电流通路，推导了故障状态下桥臂的电压、电流解析方程 ...
姜田贵 +4 more
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全球能源互联网, 2019 模块化多电平换流器是柔性直流输电技术中的重要组成部分，柔性直流电网中直流过电压对整个系统的危害很大，因此对换流器闭锁退出运行后出现过电压进行仿真和机理分析。分析了换流器中子模块的6种工作状态和MMC的等效模型，根据换流站类型分为送端和受端换流站两种情况，基于PSCAD/EMTDC平台仿真换流器因故障闭锁后直流电压的变化情况，并根据等效电路分析换流站端口直流电压的动态发展过程和机理。由仿真结果发现，PSCAD/EMTDC仿真软件具有一定的缺陷，不能真实地反映断路器的断开，会产生虚拟过电压 ...
李英彪 +4 more
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