1000MW超超临界机组直流密封油泵试转异常分析

Analysis of Abnormal Running Test of DC Sealed Oil Pump for 1000MW Ultra-Supercritical Unit

某电厂1000 MW超超临界机组单流环密封油系统直流密封油泵在调试期试转时,发电机汽/励端消泡箱均发出液位高报警。通过对消泡箱液面与密封油储油箱液面之间的黏性流动U型连通管模型进行定量计算,分析得出管道流动阻力过大是消泡箱液位高报警的根本原因,并计算出消泡箱液位高报警的临界油温为17.7℃,且油温在10℃以上单转直流密封油泵不会造成发电机进油事故的发生。通过将密封油温提高至临界报警温度以上、打开氢侧密封油箱浮球阀旁路手动门或保持交流密封油泵同步运行等措施,消除了消泡箱液位高报警及发电机进油的隐患。

When the DC seal oil pump of the single-ring type seal oil system of a 1000 MW ultra-supercritical unit in a power plant is in commissioning,the steam/excitation end defoamer box of the generator sends out a high level alarm.Through the quantitative calculation of the viscous flow U-shaped connecting pipe model between the liquid level of the defoamer and the liquid level of the sealed oil storage tank,it is concluded that the excessive flow resistance of pipeline is the fundamental reason for high alarm of liquid level of the defoamer tank.The critical oil temperature for high alarm of liquid level of the defoamer tank is calculated to be 17.7℃,and the oil temperature above 10℃will not cause the oil intake accident of the generator.By raising the sealing oil temperature above the critical alarm temperature,opening the manual bypass valve of the floating ball valve of the hydrogen side sealing oil tank or keeping the synchronous operation of the AC sealing oil pump,the hidden dangers of the high alarm of the liquid level of the defoaming tank and the oil intake of the generator are eliminated.