针对天然气管道运营后期地区等级升级造成管道风险不可接受的问题,尝试从壁厚设计角度解决该问题,提出一种考虑地区等级升级的管道壁厚优选方法。该方法在基于可靠性设计和评估(Reliability-Based Design and Assessment,RBDA)方法的基...针对天然气管道运营后期地区等级升级造成管道风险不可接受的问题,尝试从壁厚设计角度解决该问题,提出一种考虑地区等级升级的管道壁厚优选方法。该方法在基于可靠性设计和评估(Reliability-Based Design and Assessment,RBDA)方法的基础上,通过定量计算可靠度,保证管道所有地区等级风险满足社会风险的要求,同时进行管道全生命周期费用比选从而实现管道经济最优,最终选出合理管道壁厚。利用该方法对管径508 mm管道进行计算,并分别讨论地区等级升级时间、地区等级、管径对最优壁厚的影响。结果表明:管道最优壁厚随地区等级升级时间、地区等级、管径增大而增大。与RBDA方法相比,该方法考虑更加全面,可达到经济成本最小化及管道安全最大化,但该方法不能实现对未来地区等级升级的预测,需进一步研究。展开更多
Diode rectifiers-synchronous machine system has a wide range of applications in isolated power system,whose low frequency oscillation emerges under certain parameters.Considerable error is produced when the state spac...Diode rectifiers-synchronous machine system has a wide range of applications in isolated power system,whose low frequency oscillation emerges under certain parameters.Considerable error is produced when the state space averaging model is used to analyze its small signal stability.Therefore,this paper has presented a periodic orbit model of diode rectifiers-synchronous machine system to solve these problems.Using trapezoidal integration method,it is possible to derive equation of periodic orbit and its Poincaré mapping.Jacobian matrix of the Poincaré mapping of periodic orbit can be calculated by chain derivative method.Besides,stability margin index and linearized Poincaré mapping model have also been proposed.Thus small signal stability of diode rectifiers-synchronous machine system can be assessed through orbitally asymptotical stability of its periodic orbit so as to lay a foundation for isolated power system analysis and its control design.Simulation test demonstrates that the proposed model and algorithm are effective and practicable.展开更多
文摘针对天然气管道运营后期地区等级升级造成管道风险不可接受的问题,尝试从壁厚设计角度解决该问题,提出一种考虑地区等级升级的管道壁厚优选方法。该方法在基于可靠性设计和评估(Reliability-Based Design and Assessment,RBDA)方法的基础上,通过定量计算可靠度,保证管道所有地区等级风险满足社会风险的要求,同时进行管道全生命周期费用比选从而实现管道经济最优,最终选出合理管道壁厚。利用该方法对管径508 mm管道进行计算,并分别讨论地区等级升级时间、地区等级、管径对最优壁厚的影响。结果表明:管道最优壁厚随地区等级升级时间、地区等级、管径增大而增大。与RBDA方法相比,该方法考虑更加全面,可达到经济成本最小化及管道安全最大化,但该方法不能实现对未来地区等级升级的预测,需进一步研究。
基金supported by the National Natural Science Foundation of China (Grant Nos. 51077130,50977090)the National Basic Research Program of China ("973" Program) (Grant No. 2012CB215103)
文摘Diode rectifiers-synchronous machine system has a wide range of applications in isolated power system,whose low frequency oscillation emerges under certain parameters.Considerable error is produced when the state space averaging model is used to analyze its small signal stability.Therefore,this paper has presented a periodic orbit model of diode rectifiers-synchronous machine system to solve these problems.Using trapezoidal integration method,it is possible to derive equation of periodic orbit and its Poincaré mapping.Jacobian matrix of the Poincaré mapping of periodic orbit can be calculated by chain derivative method.Besides,stability margin index and linearized Poincaré mapping model have also been proposed.Thus small signal stability of diode rectifiers-synchronous machine system can be assessed through orbitally asymptotical stability of its periodic orbit so as to lay a foundation for isolated power system analysis and its control design.Simulation test demonstrates that the proposed model and algorithm are effective and practicable.