| 引用本文: | 李佳朋,李宇骏,袁枭添,贾科,宋国兵.远海风能集中接入的多端直流系统直流故障分析与故障检测方法[J].电力自动化设备,2020,40(12): |
| LI Jiapeng,LI Yujun,YUAN Xiaotian,JIA Ke,SONG Guobing.DC fault analysis and detection for offshore wind farms integration via MTDC[J].Electric Power Automation Equipment,2020,40(12): |
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| 摘要: |
| 二电平电压源换流器(VSC)和半桥模块化多电平换流器(MMC)在直流故障期间缺乏对直流短路电流的调控能力。在多端直流系统中，为了避免整个系统因换流阀的闭锁而停运，有必要在直流故障后的第一阶段(即电容放电阶段)快速识别并隔离故障。因此，对多端直流系统故障检测而言，直流故障电容放电阶段的短路电流计算至关重要。提出了适用于多端直流系统故障分析的暂态等效模型，该模型仅保留原故障网络中的高频成分，使故障初期的电路分析大为简化。基于此模型，可以得到故障线路和健全线路的故障电流解析表达式。根据故障线路和健全线路电流的差异，提出了基于暂态电流均值的故障检测方法，该方法具有计算复杂度小、耐过渡电阻能力强、采样率低等优点。通过EMTP仿真验证了暂态等效模型的准确性和故障检测方法的有效性。 |
| 关键词: 多端直流系统 直流故障分析 暂态等效模型 暂态电流均值 直流故障检测 |
| DOI：10.16081/j.epae.202008023 |
| 分类号:TM77 |
| 基金项目:国家自然科学基金资助项目(51807150,51707091, U1766209)；中国博士后基金资助项目(2019T120908)；新能源电力系统国家重点实验室开放课题资助项目(LAPS19002) |
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| DC fault analysis and detection for offshore wind farms integration via MTDC |
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LI Jiapeng1, LI Yujun1, YUAN Xiaotian1, JIA Ke2, SONG Guobing1
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1.State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China;2.State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
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| Abstract: |
| Two-level VSC(Voltage Source Converter) and half-bridge MMC are lack of the ability to control fault DC current during DC fault. Therefore, in MTDC(Multi-Terminal DC) system, it is crucial to immedia-tely identify and isolate the fault during the first period of DC fault, namely, capacitor discharging stage, other-wise the overall system might be out of operation due to the fast blocking of converter valves. The initial DC fault current analysis during capacitor discharging stage is the prior issue for fault detection in MTDC system. A transient equivalent model is proposed for fault analysis of MTDC system, in which only high-frequency components of the fault network are reserved, so the analysis in the failure period can be simplified. The analytical expression of fault current of faulty and healthy lines can be deduced based on the proposed model. Based on the current difference between fault lines and healthy lines, a fault detection method based on the average value of transient current is further proposed, which has the advantage of rela-tively low computation burden, high fault resistance tolerant ability, and relatively low sampling frequency. Numerical studies carried out in EMTP verify the accuracy of the proposed transient equivalent model and the effectiveness of the proposed fault detection method. |
| Key words: multi-terminal DC system DC fault analysis transient equivalent model average value of transient current DC fault detection |
