DESIGN AND IMPLEMENTATION OF A NEW GENERATION DISTRIBUTED EMS PLATFORM

Based on an open architecture model of distributed real time system, a new generation platform of EMS is designed and implemented . Server side components are developed in Linux system, including event bus, data access bus, and some SCADA/EMS applications. Client side components include maintenance and operation control subsystems. Based on Web Java technology, maintenance subsystem is to be accessed anywhere. While operation control subsystem is implemented into Java application to obtain good responsibility and reliability. In particular, the platform can run on multi vendor heterogeneous computers, and be easy to integrate the clients of EMS/DMS/DMIS into one workstation. Bench mark testing shows that the new platform could satisfy the requirements of EMS.     

Dynamic Protective Control Strategy for Distributed GenerationSystem with Fixed-speed Wind Turbines

The characteristics of induction generator based fixed-speed wind turbines(FSWT)are investigated.The impacts of different execution time in protective operations are studied under different fault duration and various wind velocity situations,e.g.,FSWT stabilities of load shedding in distribution systems.Based on this research,a dynamic protective control strategy for a distributed generation system(DGS)with FSWT is proposed.Finally,simulation results demonstrate the effectiveness of the strategy.     

Reforms in the Chinese Electric Power Sector

This paper summarizes the reforms happened in the Chinese electric power sector in recent years.Although some major measures for the electricity reforms have made progress in a phase sense,including direct trading between major electricity producers and consumers,energy-saving power dispatch and the increase of electricity prices,the deployment of these reforms into practice is facing more difficulties than expected.The author also gives an outlook for the electric power reform in the 12th Five-Year Plan period,and deems that the government may not take substantial steps to reform the electricity system.Reforms on the electricity system will continue in a more moderate manner and focus on electricity prices.     

Achievements and Prospects of Wind Power Prediction

Wind power prediction is crucial to the operation of the power system accommodating a large amount of wind power. From the perspective of power dispatch, this paper discusses the current situations of the technology, system building, prediction errors, the index for evaluating wind power prediction system and the main bodies responsible for the prediction. It delves into the existing problems such as incomplete basic data, poor prediction accuracy, short prediction time scale, as well as lacking of prediction in most wind farms. Suggestions on improvement are proposed including enhancing the construction of wind power prediction system on both the grid side and the wind farm side, speeding up the development of ultra-short term wind power prediction system, deepening the research on wind power prediction technology, strengthening the construction of technical standard system and carrying out cross-sector cooperation.     

基于电流源型变换器的多端直流风电系统

A current source converter based multi-terminal direct current(DC)wind energy conversion system(WECS)is proposed.The current source DC/DC converter is adopted to connect a wind turbine to an inverter with maximum power point control.Each turbine is associated with a DC source by parallel-connected to a common DC link.After DC power collection,a current source inverter(CSI)using gate turn-off components is used for the grid connection due to its flexible reactive power control and short circuit protection capabilities.For such a parallel connection configuration,the CSI operates in an input voltage control mode,which maintains the DC link voltage constant.The dynamic responses of combined mechanical and electrical systems are investigated with three different operation cases.Simulation and experimental results demonstrate the feasibility and stability of the current source DC/DC converter based multi-terminal DC WECS.     

可控串联补偿装置动态模拟实验研究(上) 稳态阻抗特性

研究了可控串联补偿动态模拟的实验方案和控制装置。动模实验证明,所研制的动模装置性能可靠。着重研究了ＴＣＳＣ工作于容性微调状态时系统的运行特性,分析了ＴＣＳＣ模块的稳态等值阻抗特性及ＴＣＳＣ动模实验模块本身的回路损耗对阻抗特性的影响,包括调制电感及发电机出力对ＴＣＳＣ阻抗特性的影响。理论计算与ＥＭＴＰ数值仿真都证明了动模实验结论的正确性。     

STUDY ON VISUAL MODELING AND SIMULATION OF GOVERNING SYSTEMS FOR PUMPED STORAGE UNITS

Conventional modeling and simulation have difficulty in modifying a model and its parameters, therefore poor in efficiency. MATLAB software has greatly progressed. However, it is necessary for MATLAB users to have modeling techniques and a deep understanding of the modeled system. The visual distributed object oriented modeling and simulation platform of governing systems for pumped storage units and Francis turbines is proposed. Based on the MATLAB with Simulink, an open model library specific to the governing systems for pumped storage units and user friendly graphic interface are developed. The library features up to five standard modular models for per section with the uniform inputs outputs so that it is not indispensable for users to have the professional knowledge and modeling experience, and it is easy to configure a system with a mouse. The study on stability of a governing system under black start conditions is preliminarily conducted on this platform.     

HYBRID SMART AUTOMATION SYSTEM FOR HYDROPOWER PLANTS

Disadvantages existing in current automation systems of HPP (hydropower plants) are analyzed. Based on Fieldbus and IAM (i ntelligent actuation and measurement) technologies, a type of ICMMS (intelligent control maintenance technical management system) for HPP is presented, and its structure, functions, characters, implementation methods are discussed. For the sake of current technical feasibility and future development, HSAS（hybrid smart automation system) as a new type of automation systems is proposed for HPP. T he overall structure of this system is based on fully distributed Fieldbus archi tecture. Not only the Fieldbus based IAM components, but also the traditional a utomation devices can be integrated into this system. So the HSAS is a fully dis tributed and realizable solution for the automation system of HPP. A HSAS sol ution for large scaled hydropower generating units is also presented, with int egrated, distributed, open, and intelligent features.     

Current status and challenges in PEMFC stacks, systems and commercialization

Polymer electrolyte membrane fuel cells(PEMFCs)operate atlowtemperatures(60~80℃),offer a fast start-up and shut downti me(few minutes),fast response to changing electric loads,andcan sustain unli mited thermal cycles·They are ideally suited fortransport…     

Xilinx FPGA system generator在伺服电机控制中的应用

为了避免编写FPGA语言HDL代码的烦琐性,借助于Simulink集成工具箱中Xilinx系列FPGA独有的System Generator模块,围绕3种伺服电机控制应用进行了仿真和实验研究。首先,根据3种伺服电机控制所需PWM信号波形,利用System Generator建立Simulink仿真框图;其次,在Simulink仿真结果正确的基础上生成HDL代码;然后,利用ISE的仿真配套软件ModelSim对HDL代码仿真测试;最后,在ModelSim仿真结果正确的基础上将代码载入FPGA硬件,并利用ChipScope Pro对PWM信号进行实验测试。实验结果与仿真结果的吻合,表明此方法简单易行,具有一定的实际应用价值。     

现代嵌入式系统协同设计方法

本文首先阐述了现代嵌入式系统软硬件协同设计的一般方法,对其主要的设计步骤--系统描述、软硬件功能划分、协同仿真以及系统测试验证进行了分析与研究,同时,对各个过程中应该注意的关键问题和重点进行了着重强调.最后以此为基础,给出了用此方法完成嵌入式图像处理控制系统设计的实例.利用这种方法,大大提高了设计的可行性,降低了工作的难度,减少了系统设计周期,提高了设计质量,对嵌入式系统协同设计具有很好的实用性和借鉴性.     

基于状态监测与系统风险的老化变压器更新策略

This paper presents a replacement strategy for an aged transformer based on condition monitoring and system risk.The condition monitoring measurements are used to estimate the insulation age of the transformer.The unavailability because of transformer aging failure is calculated using the insulation age instead of the traditional natural age.The system risk is assessed using the total unavailability from both aging and repairable failures.The expected damage cost and benefit due to delaying the replacement of the transformer are evaluated.The best replacement timing is determined as the year when the replacement of the transformer reaches the maximum net benefit.A case study for two aged transformers in a utility system demonstrates the effectiveness of the proposed method.     

Designing Technical Standard System of Strong & Smart Grids Based on SLO Principle

In this paper,the international status of the research on the technical standards of smart grids is overviewed An approach using the SLO principle to establish the technical standard system of strong &...     

Clustering Analysis of Black-start Decision-making witha Large Group of Decision-makers

The optimization of black-start decision-making plays an important role in the rapid restoration of a power system after a major failure/outage.With the introduction of the concept of smart grids and the development of real-time communication networks,the black-start decision-makers are no longer limited to only one or a few power system experts such as dispatchers,but rather a large group of professional people in practice.The overall behaviors of a large decision-making group of decision-makers/experts are more complicated and unpredictable.However,the existing methods for black-start decision-making cannot handle the situations with a large group of decision-makers.Given this background,a clustering algorithm is presented to optimize the black-start decision-making problem with a large group of decision-makers.Group decision-making preferences are obtained by clustering analysis,and the final black-start decision-making results are achieved by combining the weights of black-start indexes and the preferences of the decision-making group.The effectiveness of the proposed method is validated by a practical case.This work extends the black-start decision-making problem to situations with a large group of decision-makers.     

基于RTDS的实时仿真自动测试系统研发

通过分析目前仿真自动测试的现状,提出了基于命令行交互实现仿真自动测试的新方法。对实现过程中的命令交互方式、映射方式及测试结果获取等关键技术给出了具体实现方案,详细介绍了系统的硬件结构和软件实现,并结合具体实例论述了自动测试流程和方法。     

Look Back Transmission Planning Around Three Gorges

In view of its huge installed capacity and very complex transmission system,the design process of China’s Three Gorges Hydropower Station had been repeatedly demonstrated for more than ten years.The smooth construction,bringing into production and operation show that the planning scheme for Three Gorges power transmission project is successful.In this paper the design course of Three Gorges power transmission system is retrospected;the main planning schemes for Three Gorges power transmission system are reviewed;and the design results in different design stages are summarized.     

Method of Evaluating Social Benefit of Energy-Conservation Based Generation Dispatching in Guangdong Province

Energy-conservation based generation dispatching is the revolutionary change in operation mode which could reduce energy consumption and pollutant emissions, promote power industry restructuring, and achieve sustainable development. Social benefit evaluation of the energy-conservation based generation dispatching under the new situation and environment has come into being as an important theoretical issue. A new scenario analysis based social benefit evaluating method, which is implemented by comparing the energy consumption and pollutant emissions of different scenarios defined by the key indicators, i.e., load factor and coal consumption structure, is proposed in the paper. Then the composition of social benefit is analyzed from the point of the dispatching mode and the coal consumption structure. The method proposed is of clear physical meaning. It is not only practical, but also applicable for the implementation of energy-conservation based generation dispatching in different phases and with different goals.     

基于WAMS和曲线相似的同调机群识别方法*

提出了一种基于曲线相似的电力系统同调机群辨识新方法。首先获取WAMS实时监测得到的功角轨迹曲线作为基础数据,根据离散曲线相似性的定义,将各发电机的轨迹曲线分段,借助遗传算法确定分段轨迹之间的最优相似距离,保存了轨迹段的局部特性。然后整合各段相似距离得到各发电机之间的整体相似度并以此作为聚类指标,再利用层次聚类法实现多机系统同调机组分群。该方法简单可行,不受系统模型参数和故障类型的限制。最后对IEEE39节点系统进行分析计算,该仿真实验佐证了所提算法的有效性。     

A Novel Grid Synchronization Control of Doubly-fed Induction Generator

The dynamic performance of doubly-fed induction generator(DFIG) before and after connection is analyzed based on corresponding mathematical models and transfer functions in decoupled vector control.The parameter tuning methods of rotor current regulator before and after connection are given.To reach same dynamic performance the parameters should take different values and be switched before and after connection.However on one hand the closing moment of stator contactor is difficult to get as the feedback signal is usually twenty millisecond delay or so.The delay in parameter switching will affect rotor current and torque dynamics during the delayed period after connection. On the other hand parameter switching is troublesome.Hence a synchronization control strategy without parameter switching is proposed and analyzed in detail,which has linear rising exciting current to avoid current overshooting. The dynamic performance of the proposed strategy is analyzed in frequency domain and implemented on a DFIG experimental platform subsequently.The proposed synchronization strategy is validated by experimental results.     

Research on Testing Technologies of Network System in Smart Substations

The network structures of smart substations and the characteristics of industrial Ethemet switches are analyzed.The testing technologies of network systems based on smart substations are specifically e...