基于短时能量的多端柔性直流单极接地故障线路识别方法
发布时间：2018-11-08 19:21
【摘要】：采用小电流接地方式的模块化多电平多端柔性直流输电系统(MMC based multi-terminal HVDC,MMC-MTDC)发生直流线路单极接地后,所有非故障极线路电压升高为额定值的2倍,威胁线路和设备安全,因此,需要快速识别并切除故障线路,以恢复MMC-MTDC系统的正常运行。而小电流接地方式的MMC-MTDC系统单极接地后,无稳态故障电流,且各直流线路稳态电压基本相同,无法依靠稳态电压、电流量来识别故障线路。分析了MMC-MTDC单极接地时线路对地电容电流暂态变化特性,提出采用线路两端的暂态差流作为区分故障线路和非故障线路的依据;进一步通过计算线路两端差流的短时能量来扩大故障线路和非故障线路的差异,减少暂态过程对故障线路识别的影响,达到可靠识别故障线路的目的。在PSCAD中搭建四端MMCMTDC系统进行仿真,结果表明故障线路两端差流短时能量远大于非故障线路两端差流短时能量,并且该故障线路差动电流短时能量波动较小,能可靠识别接地线路。
[Abstract]:After unipolar grounding of DC line occurs in modularized multilevel flexible HVDC transmission system (MMC based multi-terminal HVDC,MMC-MTDC) with small current grounding mode, the voltage of all non-fault pole lines increases twice as high as the rated value. It is necessary to quickly identify and remove the fault lines in order to restore the normal operation of the MMC-MTDC system. However, there is no steady-state fault current after single-pole grounding in MMC-MTDC system with small current grounding mode, and the steady voltage of each DC line is basically the same, so it is impossible to identify the fault line by steady-state voltage and current. In this paper, the transient characteristics of line to ground capacitive current are analyzed when MMC-MTDC monopole is grounded, and the transient differential current at both ends of the line is proposed as the basis for distinguishing fault line from non-fault line. Furthermore, the difference between fault line and non-fault line can be enlarged by calculating the short time energy of differential current at both ends of line, and the influence of transient process on fault line identification can be reduced, and the purpose of reliable identification of fault line can be achieved. A four-terminal MMCMTDC system is built in PSCAD for simulation. The results show that the short time energy of differential current at both ends of fault line is much larger than that of non-fault line, and the short time energy fluctuation of differential current of fault line is small. Reliable identification of ground wiring.
【作者单位】： 新能源电力系统国家重点实验室(华北电力大学);中国电力科学研究院;
【基金】：国家重点基础研究发展计划项目(973项目)(2012CB215206) 国家自然科学基金项目(51407067;51222703) 高等学校学科创新引智计划资助(B08013)~~
【分类号】：TM721.1
本文编号：2319421
[Abstract]:After unipolar grounding of DC line occurs in modularized multilevel flexible HVDC transmission system (MMC based multi-terminal HVDC,MMC-MTDC) with small current grounding mode, the voltage of all non-fault pole lines increases twice as high as the rated value. It is necessary to quickly identify and remove the fault lines in order to restore the normal operation of the MMC-MTDC system. However, there is no steady-state fault current after single-pole grounding in MMC-MTDC system with small current grounding mode, and the steady voltage of each DC line is basically the same, so it is impossible to identify the fault line by steady-state voltage and current. In this paper, the transient characteristics of line to ground capacitive current are analyzed when MMC-MTDC monopole is grounded, and the transient differential current at both ends of the line is proposed as the basis for distinguishing fault line from non-fault line. Furthermore, the difference between fault line and non-fault line can be enlarged by calculating the short time energy of differential current at both ends of line, and the influence of transient process on fault line identification can be reduced, and the purpose of reliable identification of fault line can be achieved. A four-terminal MMCMTDC system is built in PSCAD for simulation. The results show that the short time energy of differential current at both ends of fault line is much larger than that of non-fault line, and the short time energy fluctuation of differential current of fault line is small. Reliable identification of ground wiring.
【作者单位】： 新能源电力系统国家重点实验室(华北电力大学);中国电力科学研究院;
【基金】：国家重点基础研究发展计划项目(973项目)(2012CB215206) 国家自然科学基金项目(51407067;51222703) 高等学校学科创新引智计划资助(B08013)~~
【分类号】：TM721.1
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1 孟永鹏,贾申利,荣命哲;短时能量分析法在断路器机械状态监测中的应用[J];西安交通大学学报;2004年12期
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