检索结果-内蒙古大学图书馆

Multi-swing stability assessment approach based on variation rate of transient energy for power systems

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2007年第16期27卷 13-18页

作者： Song, Fang-Fang Bi, Tian-Shu Yang, Qi-Xun Key Lab. of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China

The lack of quantitative stability analysis software for power system is one of the main reasons for losing good chance to implement the emergency control and even finally resulting in the large outage. Recently, the rapidly developing wide area measurement system (WAMS) gives a new way for quick on-line quantitative transient stability assessment. Starting with the single machine energy function, the relationship between the variation rate of transient unbalance energy and multi-swing stability was analyzed in detail, and the corresponding characteristic of the variation rate of transient energy was proved. Then, a new multi-swing stability assessment criterion based on WAMS was proposed. Numerical simulations were conducted on 6-machine 22-bus system of China electric power research institute to demonstrate the effectiveness of this criterion.

关键词： Electric power systems

来源：评论

学校读者我要写书评

暂无评论

Three design schemes of compensation currents for D-STATCOM used for unbalanced load

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2007年第1期31卷 75-79页

作者： Zhu, Yongqiang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control School of Electric and Electronic Engineering North China Electric Power University Beijing 102206 China

Three design schemes of compensation currents for D-STATCOM in delta connection used for unbalanced load compensation are introduced. They are the schemes based on compensation principle of admittance, no zero sequence component design and an optional design method of maximum minimizing phase current. Comparisons are made considering technical indexes and engineering significance among the proposed three schemes. In serious unbalanced operating conditions, the obvious difference in amplitude among the compensation currents in three phases may lead to one or two phase overloading and the compensation capability is restricted. The optional design makes the compensation currents in three phases to be equal or close to each other as possible as it can, which is helpful to ensure the D-STATCOM having high-usage and desirable compensation effect. Similar performance can be obtained to some extent with the simpler scheme of no zero sequence component design.

关键词： Electric loads

来源：评论

学校读者我要写书评

暂无评论

HV power equipment running state detection based on image processing and recognition

HV power equipment running state detection based on image pr...

引用

2006 International Conference on power system Technology, powerCON2006

作者： Shutao, Zhao Baoshu, Li Xiaohui, Zhu North China Electric Power University Baoding 071003 China Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Baoding 071003 Hebei Province China North China Electric University

ISBN: (纸本)1424401119

Aimed at the necessary on the automatic detection level in unattended substation, a new method which monitoring and diagnosis the high-voltage (HV) power equipment running state based on image processing is put forward. Image processing techniques realize and strengthen the capability of the human vision. It is a non-contact measurement method, which can monitor the HV power equipment running state online. In recent years, it is widely applied in many fields and gets plentiful and substantial success. The HV power equipment running state detection process is introduced in this paper. After image preprocesses and feature extraction, the automatic target recognition algorithm based on the radial basis function neural network (RBFNN) is presented. © 2006 IEEE.

关键词： HVDC power transmission

来源：评论

学校读者我要写书评

暂无评论

Study of image recognition used for unattended substation

Study of image recognition used for unattended substation

引用

2006 International Conference on power system Technology, powerCON2006

作者： Jun, Yang Xin, Ai Xiufang, Jia Yansong, Li Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Deshengmenwaizhuxinzhuang Beijing 102206 China Electric Power Company of Jinzhou Engineering Technology Department Liaohe Petroleum Exploration Bureau Linghai City Liaoning Province 121209 China

ISBN: (纸本)1424401119

It is a trend to construct unattended substation in power system *** paper systematically analyses the superiority and limitation of MATLAB and Visual C++ and illustrates how to compile m-files to cpp-files by MATLAB engines and integrate cpp-files code into existing C++ projects by Visual C++ to realize intelligent function on image recognition used for unattended substation. The intelligent function can effectively test illegal intrusion and fires through the detection and recognition of moving goals by three-image difference method and self-adapting threshold value segmentation algorithm and detect situations of disconnection link by use of image crop and image index processing and give warnings to alarm system. Because of lacking of brightness of image or nonlinear brightness and being influenced by kinds of noise,this paper determines to adopt contrast enhanced algorithm and high-frequency enhanced algorithm to repair grey-scale distribution and uses median filtering to remove noise of *** the end,this paper brings forward the expectation about the image recognition of the unattended substation. When non-uniform of image illumination distribution, grey-scale of background changes largely and image segmentation has not the fittest threshold, so the paper uses self-adapting threshold segmentation algorithm to gain the image segmentation. © 2006 IEEE.

关键词： Image recognition

来源：评论

学校读者我要写书评

暂无评论

Study on Transient Characteristics of Grid-connected Wind power Generators

Study on Transient Characteristics of Grid-connected Wind Po...

引用

2007 International power Engineering Conference (IPEC2007), vol.2

作者： Yan Zhang Li Lin Yihan Yang Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China

With rapid development of wind power generation, it's necessary to study the dynamic characteristics of wind power generators when a fault occurs in the grid to assure the safe and stable operation of the wind farm. At present, the widely used wind power generators in the whole world are squirrel cage induction generator (SCIG) and doubly fed induction generator (DFIG). The models of SCIG wind power generation system and DFIG wind power generation system connected with the grid are built, and their transient operation characteristics are studied. A new control measure is put forward to improve the transient performance of the DFIG, which is proved effective through the simulation. Also the impact of the control measure on the SCIG running in parallel with the DFIG is also investigated.

关键词： Doubly fed induction generator Squirrel cage induction generator Transient operating characteristic Voltage control

来源：评论

学校读者我要写书评

暂无评论

Load Modeling Considering Distributed Generation

Load Modeling Considering Distributed Generation

引用

power Tech Conference

作者： Wang Jili He Renmu Ma Jin Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education North China Electric Power University Beijing China

Distributed generation is regarded as the developing direction of the power system in 21 century. Because distributed generation always connects with the distribution system, which has great influence on every aspects of power system. This paper studied the influence of distributed generation on load modeling. When the influence of distributed generation is not negligible, the composite induction motor load model can't effectively describe the actual load characteristic. This paper proposes a new load model-asynchronous generator +ZIP. The validity of the proposed load model is also testified via the comparison and contrast from a great deal of simulations. Then, composite induction-motor and asynchronous generator +ZIP load models were unified in one program.

关键词： Load modeling Distributed control power system modeling power system dynamics power system simulation Induction generators power systems Helium power system transients power system stability

来源：评论

学校读者我要写书评

暂无评论

A new method for hybrid non-linear state estimation with PMU

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2007年第4期31卷 28-32页

作者： Qin, Xiaohui Bi, Tianshu Yang, Qixun Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China Sifang Research Institute North China Electric Power University Beijing 102206 China

A new method for hybrid non-linear state estimation with phasor measurement unit (PMU) is proposed, in which the direct voltage phasor measurement is transformed into indirect equivalent branch current measurement to conduct the hybrid iteration with SCADA measurement. The indirect measurement errors caused by constructing the equivalent current modification are also analyzed and calculated in detail. The accuracy of the hybrid estimation algorithm is analyzed qualitatively and calculated quantitatively. The theoretic analysis and simulation results demonstrate that the proposed method has higher estimation precision and better performance in convergence time and filtering effect.

关键词： State estimation

来源：评论

学校读者我要写书评

暂无评论

Modeling of the Wind Turbine with a Permanent Magnet Synchronous Generator for Integration

Modeling of the Wind Turbine with a Permanent Magnet Synchro...

引用

IEEE General Meeting power& Energy Society

作者： Ming Yin Gengyin Li Ming Zhou Chengyong Zhao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China electric Power University Beijing China

The paper presents the dynamic model and control schemes of a variable speed pitch wind turbine with permanent magnet synchronous generator (PMSG). The model includes a PMSG model, a pitch-angled controlled wind turbine model and a drive train model. The drive train model uses one-mass model to represent the mechanical characteristics of the generator set. The generator model is established in the dq-synchronous rotating reference frame. The wind turbine model details the mechanism of variable speed operation of the turbine by a pitch control. The control schemes in the paper include a pitch angle control for the wind turbine and a speed control for the generator. The pitch angle control uses wind speeds and electric power output as the input signals to ensure normal operation in high wind speed. The speed control is realized through field orientation where the d-axis current is set to zero and the q-axis current is used to control the rotational speed of the generator according to the variation of wind speed. In order to verify the presented model and the control strategy, simulations with MATLAB/Simulink software have been conducted. Simulation results prove the validity of the model and the control schemes.

关键词： Wind turbines Permanent magnets Synchronous generators Mathematical model Mechanical variables control Electric variables control Wind speed Magnetic variables control Velocity control Wind energy generation

来源：评论

学校读者我要写书评

暂无评论

Reallocating-damping theory of PSS and HVDC modulation

Reallocating-damping theory of PSS and HVDC modulation

引用

2007 International power Engineering Conference (IPEC2007), vol.2

作者： Shanshan Zhao Li Lin Xiangyu Tao Yonghua Yin Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control and China Electric Power Research Institute North China Electric Power University China Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control Ministry of Education North China Electric Power University Beijing China China Electrical Power Research Institute China

In an AC/DC large-scale interconnection power grid, there are many problems to be solved. Among these, small-signal stability is extremely important. In this paper, based on the reallocating -damping theory of PSS, reallocating-damping theory of HVDC modulation is proposed, that variation of gain of HVDC modulation doesn't influence the system general damping. It is also proved that reallocating-damping theory unifies PSS and HVDC modulation, which are both damping control measures. Mathematics deduction is given in detail. The possible negative effect caused by PSS and HVDC modulation is analyzed. A number of cases are tested such as a 12-generator system, 2DC system and a real power system.

关键词： Low frequency oscillation PSS HVDC modulation Reallocating-damping theory AC/DC hybrid grid Damping characteristics

来源：评论

学校读者我要写书评

暂无评论

Decoupling control for Multiterminal VSC-HVDC Based Wind Farm Interconnection

Decoupling Control for Multiterminal VSC-HVDC Based Wind Far...

引用

IEEE General Meeting power& Energy Society

作者： Gengyin Li Ming Yin Ming Zhou Chengyong Zhao Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University Beijing China

In the paper multiterminal voltage source converter based HVDC (VSC-HVDC) is proposed to interconnect wind farms to AC grids. The method highlights the control at the level of wind generator cluster that comprises several permanent magnet synchronous generators without the primary converters on themselves. For the cluster control, active and reactive power decoupling scheme is applied to adjust the rotational speed of the cluster according to wind speed. The paper studies the schemes to control grid side converter based on the philosophy of linear decoupling control, which aims to control the DC voltage as well as the reactive power of VSC-HVDC. In the proposed control scheme, the two goals are achieved by controlling the q- and rf-axis components of the grid's fundamental current. Simulation has been performed using engineering software Matlab/Simulink to verify the interconnection method and validate the control scheme as well.

关键词： Wind farms Converters power conversion Voltage control Synchronous generators Reactive power control HVDC transmission Wind energy generation Permanent magnets Wind speed

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：