联合运行水电站水力机械系统小波动稳定性研究

推导了水电站联合运行条件下的系统等效惯性时间常数、总出力变化以及机组控制方程,结合水电站实际工程的水道布置及机械特性,分别建立了系统的小波动稳定理论分析模型和小波动过渡过程时域仿真模型。通过理论分析,给出联合运行条件下系统的稳定性特征,采用数值仿真,模拟了负荷扰动时系统参数的小波动过渡过程,并与孤网条件下单个水电站的稳定性及调节品质进行了比较。结论表明:相对于孤网运行,水电站联合运行可增加系统的稳定性,改善系统的调节品质,联合运行改变了机组的调节方式,系统总出力与负荷平衡,机组无需保持自身出力为常数;联合运行时,调速器参数可在系统稳定域内选取相对较小值,在保证系统稳定的前提下,可加快调节过程,改善调节品质。

Investigation on small fluctuation in governor turbine hydraulic system under interconnected operation

The equivalent mechanical starting time of the interconnected system, the variation of the total output and the mathematical model of the unit under interconnected operation are presented in this paper. According to the parameters of the governor-turbine-hydraulic (GTH) system of two practical hydropower stations, the theoretical model for analyzing the stability of the GTH system and the numerical model for simulating the small fluctuation of the GTH system under small load disturbance are established respectively. The stable region of the GTH system under interconnected operation is given by using theoretical analysis. The small fluctuation process during the load disturbance is simulated with numerical model and the results are compared with those under isolated operation as well. The results show that the system is much more stable under interconnected operating condition because the unit''s regulating mode is changed. Instead of keeping the unit''s output constant under isolated condition, it is stable when the total output of the interconnected system is balanced to the total load demand. When the GTH system is operating under interconnected condition,the parameters of the governor should be selected with small value,which can accelerate the regulating process and improve the regulating quality.