摘要
串补电容可能引发次同步暂态扭矩放大,极端情况下在0.5 s内导致汽轮发电机组大轴损伤,常规扭应力保护来不及保护。提出一种快速保护方法,该方法将电流或有功功率的工频变化量越限作为启动判据,波动转速幅值越限作为动作判据。针对XM地区M电厂的机组,选取12个算例进行时域仿真分析,结果表明,波动转速幅值与扭振幅值有较好的一致性,近似成正比;在仿真的转速中叠加现场实测的转速噪声信号,对保护算法及保护逻辑进行验证,结果表明扭振较轻时保护不动作,扭振较重时保护快速动作,最恶劣工况下暂态扭矩放大导致的疲劳值可降低至15%以下。需注意机组脱网之后仍存在扭振的影响,保护定值应有足够裕度。
The transient torque amplification which may be resulted from series compensated capacitor could lead to fatigue cracks in the shaft of a large steam turbine generator within 0.5 seconds,the conventional torsional stress relay cannot work in time to protect in this extreme case.A fast protection method is proposed,which takes the over-component of power frequency variation of current or active power as the pick-up criterion,and the over-amplitude of fluctuation speed amplitude as the operation criterion.For the turbine-generator units of the Power Plant M in XM grid of China,twelve cases are selected for time domain simulation study.The simulative results show that the speed deviation amplitudes are obviously consistent with the torsional torque amplitudes and they are approximately proportional.Finally,the speed signals of the simulation cases are superimposed with on-sited measured speed noises,and then the protection algorithm and logic are verified.The study shows the fast protection doesn’t operate when torsional vibration is slight,but trips fast when torsional vibration is severe,so that the fatigue value resulted from shaft torque amplification in the worst case will be decreased to less than 15%.It should be noted that the effect of torsional vibration still exists after the generator is disconnected from the grid,and the protection setting threshold should have sufficient margin.
作者
张琦雪
马志恒
肖鹏
都成刚
王凯
杨扬
周荣斌
王强
王光
ZHANG Qixue;MA Zhiheng;XIAO Peng;DU Chenggang;WANG Kai;YANG Yang;ZHOU Rongbin;WANG Qiang;WANG Guang(NR Electric Co.,Ltd.,Nanjing 211102,China)
出处
《电力自动化设备》
EI
CSCD
北大核心
2020年第11期213-218,共6页
Electric Power Automation Equipment
关键词
汽轮发电机
次同步谐振
次同步振荡
扭振保护
暂态扭矩放大
电容串补
steam turbine generator
subsynchronous resonance
subsynchronous oscillation
torsional vibration protection
transient shaft torque amplification
series compensated capacitor
