考虑原动机调速特性的中压直流发电机组动态仿真模型

Dynamic Simulation Model of MVDC Generating Set Considering the Speed Regulation Characteristics of Prime Movers

鉴于原动机调速特性对舰船中压直流(MVDC)发电机组运行影响的重要性,该文基于十二相同步发电机及其三相交流励磁机数学模型提出MVDC发电机组动态建模方法,以解决多相整流发电机及其励磁系统难以考虑原动机动态调速特性的难题。以某型燃气轮机整流发电机组动态仿真模型为基础,建立了频率不同的十二相同步发电机与三相交流励磁机组合模型,阐述原动机调速与发电机励磁调压相互耦合的计算流程。实测与仿真结果表明,该型燃气轮机发电机组在突加20%负载工况时转速跌落较大,且转速恢复过程需约20 s,但MVDC发电机组通过调节励磁系统可在1 s内使直流母线电压恢复稳定,从而为负载提供稳定直流功率输出。在校准仿真模型的基础上,通过系统分析突加不同比例负载时的转速、燃油流量、励磁电流、输出电压等性能参数变化规律,获取了燃发机组允许突加负载上限约为30%的运行边界认知,为MVDC发电机组励磁系统设计以及如何预留充足的短时强励能力提供了理论支撑。

Compared with the medium voltage AC(MVAC)integrated power system,the medium voltage DC(MVDC)integrated power system eliminates the influence between the rotational speed of the prime mover and the frequency of the power grid,providing an effective solution for the parallel power supply of multiple gas turbine generator sets,diesel engine generator sets,and steam turbine generator sets with different speed regulation characteristics and magnitude differences in capacity.In MVDC integrated power systems,a multi-machine parallel power supply is commonly used to improve fuel operation economy and power supply reliability.If a single unit trips,it will trigger a dynamic process of sudden load application to units on the grid.The stability of the grid voltage is crucial at the beginning of the design of the MVDC integrated power system,which is closely related to the speed regulation of the prime mover and the voltage regulation of the generator.Therefore,it is necessary to establish a dynamic simulation model for MVDC generator units considering the speed regulation characteristics of the prime mover.Based on traditional modeling methods for synchronous generators,this paper takes a time base value of 1,The dynamic performance of a real system under the no-load sudden load condition is simulated,comparing the experimental data from actual MVDC gas-turbine power generation units under a sudden load condition of 20%.The comparison reveals consistent rotational speed output waveforms(Fig.A1)and DC voltage output waveforms(Fig.A2).Key dynamic performance indicators are analyzed,including transient speed regulation rate,transient voltage regulation rate,rotational speed,and voltage recovery time.The maximum relative error between the simulation and the experiment is 2.91%,verifying the accuracy of the dynamic performance simulation analysis of the MVDC generator set model.