当前电力系统功率振荡模式越来越复杂,且动态稳定性问题日益突显。为此列举了3种当前主流电力系统稳定器(power system stabilizer,PSS)的模型结构及原理,分析了PSS模型中有功型(PSS1A)反调产生的机理及加速功率型(PSS2B)、多频段型(PSS...当前电力系统功率振荡模式越来越复杂,且动态稳定性问题日益突显。为此列举了3种当前主流电力系统稳定器(power system stabilizer,PSS)的模型结构及原理,分析了PSS模型中有功型(PSS1A)反调产生的机理及加速功率型(PSS2B)、多频段型(PSS4B)抑制反调的原理,以及有功调节速度、PSS参数选择等因素对抑制反调效果的影响。基于实时数字仿真系统对2种电力系统稳定器模型抑制反调的效果进行了验证和比较,得出其抑制反调的原理和现场参数整定的依据。指出合理的参数配置可以减小反调的发生,提高电力系统的动态稳定性,为发电机组的稳定运行和现场试验提供参考依据。展开更多
For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the la...For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the laser power.Thermal analyses of the laser assisted machining process for inclination planes were performed.By analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination angles.In addition,the temperature distribution of the cross section after feed rate control was predicted.The correlation equation between inclination angles and adjusted proper feed rate was proposed.The results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.展开更多
文摘当前电力系统功率振荡模式越来越复杂,且动态稳定性问题日益突显。为此列举了3种当前主流电力系统稳定器(power system stabilizer,PSS)的模型结构及原理,分析了PSS模型中有功型(PSS1A)反调产生的机理及加速功率型(PSS2B)、多频段型(PSS4B)抑制反调的原理,以及有功调节速度、PSS参数选择等因素对抑制反调效果的影响。基于实时数字仿真系统对2种电力系统稳定器模型抑制反调的效果进行了验证和比较,得出其抑制反调的原理和现场参数整定的依据。指出合理的参数配置可以减小反调的发生,提高电力系统的动态稳定性,为发电机组的稳定运行和现场试验提供参考依据。
基金Project(2011-0017407)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MEST)
文摘For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the laser power.Thermal analyses of the laser assisted machining process for inclination planes were performed.By analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination angles.In addition,the temperature distribution of the cross section after feed rate control was predicted.The correlation equation between inclination angles and adjusted proper feed rate was proposed.The results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.
