液化空气储能系统甩负荷时膨胀机转子转速飞升特性研究

Characteristics of rotating speed of expander rotor in liquefied air energy storage system during load rejection

为了研究液化空气储能系统甩负荷时膨胀机转子的转速飞升问题,建立500 k W液化空气储能系统膨胀机组的动态模型,并对不同的调节阀关闭时间和转子时间常数时膨胀机组的甩负荷过程进行仿真计算和分析。结果表明:当阀门关闭时间为5 s、转子时间常数为15 s时,甩负荷过程中第1、2级膨胀机转速的超速比为142.2%,甩负荷过程用时为7071 s,第3、4级转速的超速比为141.2%,用时为4550 s;当阀门关闭时间缩短到0.5 s、转子时间常数减小到6 s时,甩负荷过程中第1、2级膨胀机转速的超速比降低至120.9%,甩负荷过程用时缩短至2552 s,第3、4级转速的超速比为120.3%,用时缩短至2200 s。因此,在液化空气储能系统甩负荷时,可以通过缩短调节阀的关闭时间来实现膨胀机转子最高转速在安全范围之内;同时,为了缩短甩负荷过程的持续时间,应适当减小转子的时间常数。

To study the speed change of expander rotor during the load rejection of liquefied air energy storage(LAES)system,a dynamic model of expander unit of 500 kW LAES system is established.The load rejection process of the expander unit with different closing times of adjustment valve and time constants of rotor is simulated and analyzed.The results show that,when the closing time of adjustment valve is 5 s and the time constant of the rotor is 15 s,the over speed ratio of expander 1’s speed to expander 2’s speed is 142.2%,and the load rejection time is 7071 s.The over speed ratio of expander 3’s speed to expander 4’s speed is 141.2%,and the load rejection time is 4550 s during the load rejection.When the closing time of adjustment valve is shortened to 0.5 s and the time constant of the rotor is reduced to 6 s,the over speed ratio of expander 1’s speed to expander 2’s speed reduces to 120.9%,and the load rejection time shortens to 2552 s.The over speed of expander 3’s speed to expander 4’s speed is 120.3%,and the load rejection time is 2200 s during the load rejection.Thus,during the load rejection of the LAES system,shortening the closing time of adjustment valve can make the maximum speed of expander rotor within the safe range.Moreover,to shorten the time of load rejection,the time constant of the rotor should be appropriately reduced.