摘要
为了深入揭示楚穗直流孤岛运行的谐波振荡机理,保证楚穗直流孤岛方式的安全稳定运行,利用PSCAD/EM TDC电磁暂态仿真软件,计算分析了楚穗直流送端孤岛系统发生故障后,系统发生振荡的规律。振荡本质上在于直流送端弱交流系统下,在约70~80 Hz左右,机组、线路、换流站无功小组构成了LC谐振电路。考虑直流系统之后,谐振的频率增大,阻抗幅值有所减小。谐振点附近,换流母线处的等效阻抗较大,对故障后直流输电系统产生的该频率段的间谐波形成了谐波放大,在换流母线和交流系统中产生较大的电压和电流波动。提出了采取高周切机控制策略以有效地抑制楚穗直流孤岛方式单极闭锁后的振荡。
Based on PSCAD/EMTDC software, this paper analyzes the post-fault oscillation of the sending side islanding system of Chuxiong--Suidong UHVDC, discovering the mechanism and proposing contermeasures. The nature of oscillation is that when the AC system is very weak, generators and lines of the AC system and the capacitors at Chuxiong HVDC station form a LC resonance circuit with a frequency of 70 ~ 80 Hz. The frequency will increase and the impedance amplitude will decrease when HVDC is taken into con- sideration. The AC system equivalent impedance near the resonance frequency is so high that the interharmonics at this frequency band caused by HVDC after faults are ampified, resulting in oscillations of AC and DC voltages and currents. Over-frequency generator shedding measurements are proposed to mitigate the oscillation after single pole blocking during islanding operation.
出处
《南方电网技术》
2014年第6期12-17,共6页
Southern Power System Technology
关键词
楚穗直流
孤岛运行
谐波谐振
抑制措施
Chuxiong--Suidong UHVDC
islanding operation
harmonic resonance
contermeasures
