摘要
当直流断路器通过其各支路间的换流清除故障电流时,会导致系统的故障暂态电气量发生变化。现有直流保护在进行原理设计时大多未考虑直流断路器动作特性的影响,因而有可能不正确动作。因此对于柔性直流输电系统,分析了直流短路故障过程中直流断路器的动作特性,给出了考虑直流断路器各换流支路故障电流熄灭特性的短路电流解析表达式,验证了现有的电流微分保护、低压过流保护以及差动保护的动作适应性,进而提出一种基于电流积分值的保护算法,解决了电流微分保护会出现误动的问题并且具有较强的抗过渡电阻和噪声的能力。最后利用PSCAD/EMTDC电磁暂态仿真软件搭建±320 kV双端柔性直流输电系统模型,仿真结果验证了理论分析的正确性和保护算法的适用性。
When the DC circuit breaker clears the fault current through the commutation between its branches, the fault transient electrical quantity of the system will change. The influence of DC circuit breaker’s action characteristics is not considered in the principle design of existing DC protection, which may cause the misoperation of the existing DC protection. Therefore for flexible HVDC(High Voltage Direct Current) system, the action characteristic of DC circuit breaker during DC short circuit fault is analyzed, the short circuit current analytical expression considering quench characteristics of fault current in each flow branch of DC circuit breaker is given, the applicability of existing current differential protection, low voltage over-current protection and differential protection is verified, and then a protection algorithm based on the current integral value is proposed, which solves the misoperation problems of the current differential protection with strong ability to resist the transition resistance and noise. Finally, a ±320 kV double-terminal flexible DC transmission system model is established by PSCAD/EMTDC electromagnetic transient simulation software. The simulative results verify the correctness of theoretical analysis and the applicability of the proposed protection algorithm.
作者
赵冠琨
贾科
王聪博
宣振文
毕天姝
ZHAO Guankun;JIA Ke;WANG Congbo;XUAN Zhenwen;BI Tianshu(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)
出处
《电力自动化设备》
EI
CSCD
北大核心
2019年第9期46-53,共8页
Electric Power Automation Equipment
基金
国家重点研发计划资助项目（2018YFB0904100）
国家电网公司科技项目（SGHB0000KXJS1800685）~~
关键词
直流断路器
直流输电
直流线路保护
适应性分析
短路电流
继电保护
DC circuit breaker
DC power transmission
DC line protection
adaptive analysis
short circuit currents
relay protection
