燃气轮发电机组短路故障时的机电耦合分析  

The coupled electro-mechanical analysis for gas turbine generators during short circuit fault

作　　者：夏凯[1,2] 孙岩桦[1,2] 张锋[1,2] 

机构地区：[1]西安交通大学机械电子与信息系统研究所,西安710049 [2]西安交通大学机械结构强度与振动国家重点实验室,西安710049

出　　处：《应用力学学报》2016年第1期55-60,180,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51275386);973计划"先进重型燃气轮机制造基础研究"项目(2013CB035705)

摘　　要：为分析短路故障下燃气轮发电机组轴系的扭振特性,建立了系统的机电耦合非线性数学模型,进行了发电机三相短路故障下轴系扭振及扭矩瞬态响应的数值分析。此外,进一步研究了轴系扭转刚度、发电机定子电阻值、励磁电流初始值等参数对发电机出口端三相短路时系统瞬态扭振的影响。分析结果表明:三相短路时,发电机产生的瞬变电磁转矩的最大值为额定转矩的6倍;电磁转矩在轴系内激发出的瞬态扭矩最大值取决于轴系的固有频率裕度,15%的固有频率裕度时的最大瞬态扭矩较10%的固有频率裕度降低了一倍;而发电机的定子电阻值只改变扭振的衰减时间常数,不改变其最大幅值,电磁转矩最大值和扭转角最大值近似与励磁电流初值的二次方成正比。研究结果可为燃气轮机发电机组轴系的设计提供参考。In order to analyze the torsional vibration of gas turbine generators during short circuit fault, a coupled electro-mechanical nonlinear mathematical model of the system is developed. Numerical simulations are performed to analyze the transient torsional vibration and torque response of the system stimulated by the 3-phase short circuit fault of the generator. Furthermore, the effects of the torsional stiffness, resistance of the generator stator and excitation current of the generator on the transient torsional vibration due to the short circuit fault are also investigated. The results show that: during the 3-phase short circuit fault, maximum transient electromagnetic torque can be 6 times the rated torque; Shaft torque stimulated by the transient electromagnetic torque depends on the natural frequency margin of the shafts; Maximum shaft torque under 15% natural frequency margin reduces 1 times than that under 10% natural frequency margin. The stator resistance only affects the time constant of the torsional vibration, whose maximum amplitude keeps unchanged. The maximum shaft torque and torsional angle are both proportional to the square of the initial excitation current. The results can be used as the reference for the design of gas turbine generator shafts.

关 键 词：燃气轮发电机组 三相短路 机电耦合 扭转振动 固有频率裕度 

分 类 号：TM331[电气工程—电机]