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以10 kV消弧线圈接地方式下的配电网接入无联接变压器的智能软开关（soft normally open point，SNOP）为背景，通过电路分析和序分量分解的方式，建立了交流故障时正负零序分量下的数学模型，分析了无变压器情况下，故障侧零序电压引发直流电压波动和非故障侧交流电压波动的内在机理，并以配电网较为关注的单相接地故障为例，详细定量地推导了直流电压和交流电压的波动公式。基于理论分析，提出了零序控制策略和模块化多电平换流器（modular multilevel converter，MMC）子模块改进策略。在PSCAD/EMTDC内建立了一个背靠背型SNOP仿真模型，仿真结果验证了交流故障下理论分析的准确性、零序控制和MMC拓扑改进策略的正确性。

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Aiming at the problems of high loss and difficulty in control of existing current-limit hybrid DC circuit breaker,the working principle,short-circuit fault breaking and control protection strategy of a DC circuit breaker topology with small inductance structure in series with mechanical switch was studied.The topology of the new type current-limit hybrid DC circuit breaker was developed,and its prototype platform was built.The processing of different modules in the prototype was analyzed and introduced in detail.Finally,through a reasonable control strategy,some verification tests such as normal switch breaking and short-circuit breaking was done on the prototype.The results indicate that the new current-limit hybrid DC circuit breaker has excellent characteristics of accelerating the conduction of solid state switch in shortcircuit commutation and cutting of the short-circuit fault quickly and effectively,at the same time,it also reduces the complexity and difficulty in control of the circuit breaker,and has obvious technical and cost advantages. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical & Electrical Engineering is the property of Mechanical & Electrical Engineering Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mechanical & Electrical Engineering is the property of Mechanical & Electrical Engineering Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)