摘要
直流微电网故障的快速检测与切除是提高其运行可靠性的关键。电流差动保护可快速有选择地切除故障,但受短路阻抗影响较大,在高阻抗短路时可能拒动。针对环形直流微电网,文中提出基于母线功率变化率的差动保护,由母线两侧功率变化率作为差动量,在区内故障时,母线功率变化率差动值大于动作值,保护动作切除故障线路。功率变化率差动值与短路电流平方及短路阻抗成正比,相比电流量保护,具有更快的故障识别速度和更高的保护灵敏度。仿真结果验证了所提保护方案具有更好的速动性、灵敏性,提高了环形直流微电网的可靠性和稳定性。
The rapid detection and removal of faults are the key to improving the operation reliability of DC microgrids.The current differential protection can remove the fault quickly and selectively.But it is greatly affected by the short-circuit impedance,and it may refuse to operate in the cases of the high impedance short circuit.For ring DC microgrids,a differential protection based on change rates of bus power is proposed.The power change rates of both sides of the bus are taken to formulate the differential value.The differential value of the change rates of bus power is bigger than the operation setting in the case of internal fault,and the protection will operate and remove the fault line.The differential value of the power change rates is proportional to the square of short-circuit current and short-circuit impedance.Compared with protection schemes based on current,it has faster fault identification speed and higher protection sensitivity.The simulation results show that the proposed protection scheme has better operation speed and sensitivity,and improves the reliability and stability of the ring DC microgrid.
作者
张伟亮
张辉
支娜
王韩伟
石海涛
ZHANG Weiliang;ZHANG Hui;ZHI Na;WANG Hanwei;SHI Haitao(School of Electrical Engineering,Xi'an University of Technology,Xi'an 710048,China;State Key Laboratory of Power System and Generation Equipment,Tsinghua University,Beijing 100084,China)
出处
《电力系统自动化》
EI
CSCD
北大核心
2020年第24期105-110,共6页
Automation of Electric Power Systems
基金
国家自然科学基金资助项目(51877175)
陕西省重点研发计划资助项目(2017ZDXM-GY-003)
陕西省自然科学基金资助项目(2017JM5100)。
关键词
直流微电网
差动保护
功率变化率
短路阻抗
速动性
DC microgrid
differential protection
change rate of power
short-circuit impedance
operation speed
