1000 MW机组循环水泵后置方式水力瞬态研究

Study on Hydraulic Transient of Circulating Water Pump Postposition Mode for 1000MW Unit

大型火力发电机组应用高位收水冷却塔配循环水泵后置方案,土建和设备费用均能大幅降低,具有较好的应用前景。系统中断、水锤压力大、泵组反转可能出现在循环水系统运行的各瞬态工况,为确保系统的安全运行,采用AFT流体分析软件对循环水系统各种瞬态工况进行深入计算分析。经分析得知,启动、运行及事故工况下,电机最大反转转速、系统水锤压力在可行的循泵液控蝶阀开关曲线过程中都在安全范围,能够确保系统安全稳定运行。高位水塔循泵后置系统匹配合理的蝶阀开关闭规律是可行的。

Large-scale thermal power units have a good application prospects because the application of high water receiving cooling tower with circulating water pump post-positioning scheme, which greatly reduces the cost of civil construction and equipment. The circulating water system has a large water supply flow and a high lift. In the various hydraulic transient processes of pumping station operation, there may be large water hammer pressure, pump inversion and system water supply interruption. In order to ensure the safe operation of the system, the AFT fluid analysis software is used to conduct in-depth calculation and analysis of various transient conditions of the circulating water system. The analysis shows that the maximum and minimum water hammer pressure of circulating water system and the maximum reverse speed control value of circulating pump motor are within the allowable range of system and specifications when the recommended law of opening and closing of hydraulic butterfly valve occurs in transient state, which will not cause damage to the system and ensure the safe and stable operation of the system. It shows that the circulating water system of this type and the designed butterfly valve are opened and closed. The law is reasonable and feasible.