摘要
上海汽轮机厂906型核电汽轮机在冬季额定负荷运行时低压转子轴向变形量(d_a)接近跳机阈值,部分核电厂曾因此降负荷。分析表明,该型汽轮机稳定运行期间影响d_a监测值的主要因素包括低压转子轴向热膨胀和由汽轮机基础热胀冷缩,停机后d_a在泊松效应影响下正向增大是正常现象。通过调节汽轮机低压进汽温度和进行凝汽器真空试验,获得了低压进汽温度和凝汽器真空对d_a的影响结果。根据设计文件和安装实测数据,低压轴向通流最小间隙位于2号低压汽缸近发电机端的第1级动叶和第2级静叶之间。根据低压轴向通流间隙最小实测值和停机后低压轴系的轴向伸长量的经验值,分析得出该型汽轮机的d_a跳机阈值应不超过+19.50 mm。最终将d_a跳机阈值由+18.10 mm调整为+19.10 mm。该型汽轮机大修期间未发现低压通流部件存在摩擦问题,调整后的d_a跳机阈值满足汽轮机运行安全需求。
The low-pressure rotor axial deformation(d_a) of Shanghai Turbine Plant 906 type nuclear power steam turbine was close to the trip threshold during rated load operation in winter, and some nuclear power plants were reduced load because of this problem. The analysis shown the main factors influencing the monitoring value of d_a during the stable operation of this type turbine included the axial thermal expansion of the low-pressure rotor and the thermal expansion and contraction of the steam turbine foundation, and the positive direction d_a increased that caused by the Poisson effect after turbine shutdown was a normal phenomenon. The effect results of low-pressure inlet steam temperature and condenser vacuum value on d_a were obtained by adjusted the low-pressure inlet steam temperature and the condenser vacuum value tests. The minimum clearance of the low-pressure axial flow path is in the second low-pressure cylinder according to the design documents and the erection data, this clearance is between the first stage rotating blade that near the end of generator side and the second stage stator blade. The d_a trip threshold of this type turbine should not exceed +19.50 mm that analyzed and got in this paper according to the actual measured minimum value of low-pressure axial flow path clearance and the empirical value of axial elongation of the low-pressure shaft after turbine shutdown. The d_a trip threshold was modified from +18.10 mm to +19.10 mm finally.There was no friction problem found in the low-pressure flow path components during the overhaul of this type turbine, the modified d_a trip threshold meets the operating safety requirements of this type turbine.
作者
郑军伟
张国军
宋文奎
于航
ZHENG Jun-wei;ZHANG Guo-jun;SONG Wen-kui;YU Hang(China Nuclear Power Engineering Co.Ltd.,Shenzhen,China,518124)
出处
《热能动力工程》
CAS
CSCD
北大核心
2020年第8期165-170,共6页
Journal of Engineering for Thermal Energy and Power
关键词
核电厂
汽轮机
跳机
阈值
低压转子
轴向通流间隙
调整
nuclear power plant
steam turbine
turbine trip
threshold
low-pressure rotor
clearance of axial flow path
modify
