For a class of non-uniform output sampling hybrid system with actuator faults and bounded disturbances,an iterative learning fault diagnosis algorithm is proposed.Firstly,in order to measure the impact of fault on sys...For a class of non-uniform output sampling hybrid system with actuator faults and bounded disturbances,an iterative learning fault diagnosis algorithm is proposed.Firstly,in order to measure the impact of fault on system between every consecutive output sampling instants,the actual fault function is transformed to obtain an equivalent fault model by using the integral mean value theorem,then the non-uniform sampling hybrid system is converted to continuous systems with timevarying delay based on the output delay method.Afterwards,an observer-based fault diagnosis filter with virtual fault is designed to estimate the equivalent fault,and the iterative learning regulation algorithm is chosen to update the virtual fault repeatedly to make it approximate the actual equivalent fault after some iterative learning trials,so the algorithm can detect and estimate the system faults adaptively.Simulation results of an electro-mechanical control system model with different types of faults illustrate the feasibility and effectiveness of this algorithm.展开更多
There are various types of distributed generators (DGs) with different grid integration strategies. The transient characteristics of the fault currents provided by the DGs are different to those of conventional synchr...There are various types of distributed generators (DGs) with different grid integration strategies. The transient characteristics of the fault currents provided by the DGs are different to those of conventional synchronous generators. In this paper, a distribution network with multi-type DGs is investigated, including consideration of DG low-voltage ride through (LVRT). The fault current characteristics of two typical DGs, i.e. an inverter-interfaced distributed generator (IIDG) and a doubly-fed induction generator (DFIG), are analyzed, considering the specific operation modes. Based on analysis of the fault characteristics, an equivalent model of the multi-type DGs under symmetrical/asymmetrical fault conditions is established. A fast-iterative fault calculation method for enhancing the calculation efficiency while avoiding local convergence is then proposed using an improved particle swarm optimization (PSO) algorithm. A simulation system of the distribution network with multi-type DGs is established in PSCAD/EMTDC. The simulation results validate the high accuracy and calculation efficiency of the proposed calculation method of the fault components. This can assist in the settings of the protection threshold.展开更多
This paper presents a methodology for constructing seismic design spectra in near-fault regions. By analyzing the characteristics of near-fault pulse-type ground motions, an equivalent pulse model is proposed, which c...This paper presents a methodology for constructing seismic design spectra in near-fault regions. By analyzing the characteristics of near-fault pulse-type ground motions, an equivalent pulse model is proposed, which can well represent the characteristics of the near-fault forward-directivity and fling-step pulse-type ground motions. The normalized horizontal seismic design spectra for near-fault regions are presented using recorded near-fault pulse-type ground motions and equivalent pulse-type ground motions, which are derived based on the equivalent pulse model coupled with ground motion parameter attenuation relations. The normalized vertical seismic design spectra for near-fault regions are obtained by scaling the corresponding horizontal spectra with the vertical-to-horizontal acceleration spectral ratios of near-fault pulse-type ground motions. The proposed seismic design spectra appear to have relatively small dispersion in a statistical sense. The seismic design spectra for both horizontal and vertical directions can provide alternative spectral shapes for seismic design codes.展开更多
在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故...在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故障短路环电流。首先根据永磁、电枢磁动势与开槽情况下的气隙磁导函数分别计算通过短路环的永磁、电枢磁链,然后通过矢量合成法得到短路环中的实际磁链以及瞬时短路电流。基于有限元方法证明解析法的正确性并探究不同短路故障匝数、不同短路故障位置对电机性能如短路环电流、相电流、推力的影响。最后制造一台样机验证有限元分析、解析法计算结果的正确性。展开更多
随着逆变型分布式电源(inverter interfaced distributed generation,IIDG)在配电网中的渗透率不断提高,且在新的故障穿越行为要求下,现有的故障分析方法已不再适用。为此,提出一种适应于最新并网规定的含PQ控制IIDG的配电网故障分析方...随着逆变型分布式电源(inverter interfaced distributed generation,IIDG)在配电网中的渗透率不断提高,且在新的故障穿越行为要求下,现有的故障分析方法已不再适用。为此,提出一种适应于最新并网规定的含PQ控制IIDG的配电网故障分析方法。该方法首先通过分析IIDG故障电流特性,提出计及控制特性的IIDG压控电流源等值模型;在此基础上,建立了故障下的含IIDG配电网节点电压方程,并针对不同IIDG间相互耦合以及公共连接点(point of common coupling,PCC)故障电压与IIDG故障电流之间存在非线性关系,提出相应的迭代修正求解方法。最后,通过算例仿真计算,验证了所提方法的可行性和有效性。展开更多
以电压源换流器为接口的分布式电源(distributedgenerator,DG)的故障电流完全由其控制策略决定,其传统的等值模型通常与常规电源类似,而忽视了控制策略的影响,造成含DG配电网故障分析存在局限性,尤其对于非对称故障情况。为此,首先对DG...以电压源换流器为接口的分布式电源(distributedgenerator,DG)的故障电流完全由其控制策略决定,其传统的等值模型通常与常规电源类似,而忽视了控制策略的影响,造成含DG配电网故障分析存在局限性,尤其对于非对称故障情况。为此,首先对DG的相间短路故障穿越控制特性进行分析,针对正序分量控制的DG提出了压控电流源等值模型;在此基础上,通过建立DG输出电流与公共联接点(point of common coupling,PCC)正、负序电压之间的关系方程式,推导出不同的相间短路故障条件下PCC正序电压的求解方程组,从而建立含DG配电网相间短路故障分析精确模型。基于DIgSILENT建立含DG配电网模型,仿真结果验证了该故障分析方法的正确性。展开更多
基金supported by the National Natural Science Foundation of China(61273070,61203092)the Enterprise-college-institute Cooperative Project of Jiangsu Province(BY2015019-21)+1 种基金111 Project(B12018)the Fun-damental Research Funds for the Central Universities(JUSRP51733B)
文摘For a class of non-uniform output sampling hybrid system with actuator faults and bounded disturbances,an iterative learning fault diagnosis algorithm is proposed.Firstly,in order to measure the impact of fault on system between every consecutive output sampling instants,the actual fault function is transformed to obtain an equivalent fault model by using the integral mean value theorem,then the non-uniform sampling hybrid system is converted to continuous systems with timevarying delay based on the output delay method.Afterwards,an observer-based fault diagnosis filter with virtual fault is designed to estimate the equivalent fault,and the iterative learning regulation algorithm is chosen to update the virtual fault repeatedly to make it approximate the actual equivalent fault after some iterative learning trials,so the algorithm can detect and estimate the system faults adaptively.Simulation results of an electro-mechanical control system model with different types of faults illustrate the feasibility and effectiveness of this algorithm.
基金supported by National Natural Science Foundation of China under Grant 51807091the China Postdoctoral Science Foundation under Grant 2019M661846Open Research Fund of Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education,EPSRC under Grant EP/N032888/1,and the International Science and Technology Collaborative Project of Policy Guidance Plan of Jiangsu Province under Grant BZ2018026.
文摘There are various types of distributed generators (DGs) with different grid integration strategies. The transient characteristics of the fault currents provided by the DGs are different to those of conventional synchronous generators. In this paper, a distribution network with multi-type DGs is investigated, including consideration of DG low-voltage ride through (LVRT). The fault current characteristics of two typical DGs, i.e. an inverter-interfaced distributed generator (IIDG) and a doubly-fed induction generator (DFIG), are analyzed, considering the specific operation modes. Based on analysis of the fault characteristics, an equivalent model of the multi-type DGs under symmetrical/asymmetrical fault conditions is established. A fast-iterative fault calculation method for enhancing the calculation efficiency while avoiding local convergence is then proposed using an improved particle swarm optimization (PSO) algorithm. A simulation system of the distribution network with multi-type DGs is established in PSCAD/EMTDC. The simulation results validate the high accuracy and calculation efficiency of the proposed calculation method of the fault components. This can assist in the settings of the protection threshold.
基金Special Scientific Research Fund of Earthquake Profession of China under Grant No.201208013National Natural Science Foundation of China under Grant No.51238012
文摘This paper presents a methodology for constructing seismic design spectra in near-fault regions. By analyzing the characteristics of near-fault pulse-type ground motions, an equivalent pulse model is proposed, which can well represent the characteristics of the near-fault forward-directivity and fling-step pulse-type ground motions. The normalized horizontal seismic design spectra for near-fault regions are presented using recorded near-fault pulse-type ground motions and equivalent pulse-type ground motions, which are derived based on the equivalent pulse model coupled with ground motion parameter attenuation relations. The normalized vertical seismic design spectra for near-fault regions are obtained by scaling the corresponding horizontal spectra with the vertical-to-horizontal acceleration spectral ratios of near-fault pulse-type ground motions. The proposed seismic design spectra appear to have relatively small dispersion in a statistical sense. The seismic design spectra for both horizontal and vertical directions can provide alternative spectral shapes for seismic design codes.
文摘在有铁心永磁直线电机(permanent magnet linear machines,PMLM)初级匝间短路故障分析中,对初级短路环电流的分析十分重要。该文提出采用磁动势–气隙磁导模型与电枢绕组故障等效模型结合的解析方法,计算任意初级位置发生的匝间短路故障短路环电流。首先根据永磁、电枢磁动势与开槽情况下的气隙磁导函数分别计算通过短路环的永磁、电枢磁链,然后通过矢量合成法得到短路环中的实际磁链以及瞬时短路电流。基于有限元方法证明解析法的正确性并探究不同短路故障匝数、不同短路故障位置对电机性能如短路环电流、相电流、推力的影响。最后制造一台样机验证有限元分析、解析法计算结果的正确性。
文摘随着逆变型分布式电源(inverter interfaced distributed generation,IIDG)在配电网中的渗透率不断提高,且在新的故障穿越行为要求下,现有的故障分析方法已不再适用。为此,提出一种适应于最新并网规定的含PQ控制IIDG的配电网故障分析方法。该方法首先通过分析IIDG故障电流特性,提出计及控制特性的IIDG压控电流源等值模型;在此基础上,建立了故障下的含IIDG配电网节点电压方程,并针对不同IIDG间相互耦合以及公共连接点(point of common coupling,PCC)故障电压与IIDG故障电流之间存在非线性关系,提出相应的迭代修正求解方法。最后,通过算例仿真计算,验证了所提方法的可行性和有效性。
文摘以电压源换流器为接口的分布式电源(distributedgenerator,DG)的故障电流完全由其控制策略决定,其传统的等值模型通常与常规电源类似,而忽视了控制策略的影响,造成含DG配电网故障分析存在局限性,尤其对于非对称故障情况。为此,首先对DG的相间短路故障穿越控制特性进行分析,针对正序分量控制的DG提出了压控电流源等值模型;在此基础上,通过建立DG输出电流与公共联接点(point of common coupling,PCC)正、负序电压之间的关系方程式,推导出不同的相间短路故障条件下PCC正序电压的求解方程组,从而建立含DG配电网相间短路故障分析精确模型。基于DIgSILENT建立含DG配电网模型,仿真结果验证了该故障分析方法的正确性。