Islanding detection is a mandatory component in grid-connected photovoltaic （PV） inverters. It is also a key issue in the photovoltaic agriculture. In this work, an overview on the islanding effect in grid-connected...Islanding detection is a mandatory component in grid-connected photovoltaic （PV） inverters. It is also a key issue in the photovoltaic agriculture. In this work, an overview on the islanding effect in grid-connected PV power systems was provided. Various islanding detection methods were introduced and their strength and weakness were dicussed. An improved islanding detection method was proposed based on active frequency drift （AFD）. The new method tolerated capacitive and inductive loads, because its perturbation signal was not offset by the non-resistive load. The new method through simulation in MATLAB/Simulink was evaluated and the advantages of the new method were demonstrated.展开更多
为计算腐蚀海底管道的剩余强度,分析海底管道的在位强度计算方法,提出一种海底管道校核方法。将腐蚀管道的强度校核分为整体强度和局部强度分析,通过ECE5模拟预测海底管道均匀腐蚀深度和局部腐蚀深度,利用原设计规范(DNV OS F101或DNV19...为计算腐蚀海底管道的剩余强度,分析海底管道的在位强度计算方法,提出一种海底管道校核方法。将腐蚀管道的强度校核分为整体强度和局部强度分析,通过ECE5模拟预测海底管道均匀腐蚀深度和局部腐蚀深度,利用原设计规范(DNV OS F101或DNV1981)计算海底管道的整体强度,采用DNV-RP-F101计算海底管道腐蚀点的局部强度,采用有限元方法对腐蚀点的局部强度进行模拟计算,为腐蚀管道的安全性评估提供依据。展开更多
基金Supported by the National Science and Technology Support Program(2014BAD06B04-1-09)China Postdoctoral Fund(2016M601406)Heilongjiang Postdoctoral Fund(LBHZ15024)
文摘Islanding detection is a mandatory component in grid-connected photovoltaic （PV） inverters. It is also a key issue in the photovoltaic agriculture. In this work, an overview on the islanding effect in grid-connected PV power systems was provided. Various islanding detection methods were introduced and their strength and weakness were dicussed. An improved islanding detection method was proposed based on active frequency drift （AFD）. The new method tolerated capacitive and inductive loads, because its perturbation signal was not offset by the non-resistive load. The new method through simulation in MATLAB/Simulink was evaluated and the advantages of the new method were demonstrated.
文摘为计算腐蚀海底管道的剩余强度,分析海底管道的在位强度计算方法,提出一种海底管道校核方法。将腐蚀管道的强度校核分为整体强度和局部强度分析,通过ECE5模拟预测海底管道均匀腐蚀深度和局部腐蚀深度,利用原设计规范(DNV OS F101或DNV1981)计算海底管道的整体强度,采用DNV-RP-F101计算海底管道腐蚀点的局部强度,采用有限元方法对腐蚀点的局部强度进行模拟计算,为腐蚀管道的安全性评估提供依据。
