相比常规同步发电机,风电机组有功响应与电网频率解耦,不具备主动频率响应能力,给高比例新能源接入电网后的频率稳定带来新挑战.风电经虚拟同步发电机技术改造后具备主动调频能力.该文针对预留备用容量及转子惯性控制两种主动调频控制方式开展现场测试,测试结果表明风电虚拟同步发电机具备有功功率支撑能力.针对现场实测发现的风电虚拟同步发电机退出调频时有功功率跃变、电磁转矩和桨距角协调控制不当等工程应用问题进行闭环优化.

In recent years,the traditional AC distribution network is facing the challenge of more and more DC power sources,DC loads and the diversification of power demand. AC and DC distribution network has gradually become the focus of research. This paper reviews the current situation of domestic and foreign technologies for AC and DC distribution network and summarizes the characteristics of existing schemes. Aiming at the core challenge to distribution network,a new technology on AC and DC distribution network based on flexible substation is proposed. Flexible substation makes the power electronic equipment highly integrated with AC and DC multi-type interfaces, and can control the power flow, highly supports the utilization of new energy and individuation of electricity consumption scheme,can support the flexible operation of grid,the demand of new energy power supply and multiple loads etc. The paper builds the system model, makes the power calculation,designs automation system,strategy of control and protection. Simulation results verify the correctness of the principle and the feasibility of the project;verify that this project can improve the interactivity and coordination of source-network-load. Finally,this paper takes "Zhangbei AC and DC distribution network and flexible substation demonstration project" as an example to introduce the world's first AC and DC distribution network based on flexible substation,and sums up the demonstration significance of the AC and DC distribution network's development.

虚拟同步发电机(virtual synchronous generators,VSG)技术可以使新能源具有频率和电压支撑能力,因此得到广泛关注。目前虚拟同步机的技术路线可以分为电压控制型和电流控制型两大类。现有研究多聚焦于电压控制型VSG,而对电流控制型VSG研究较少。主要研究了电流控制型VSG的并网稳定问题,首先建立了电流控制型VSG的小信号模型,计算得到了系统特征根,分析了系统中各模态的阻尼特性。在此基础上,研究了电流控制型VSG控制参数对其稳定性的影响,并对电流控制型VSG在不同电网条件下的稳定性及其并网适应性进行了分析。研究结果表明,VSG控制环节对电流控制型VSG的稳定性存在显著影响,电流控制型VSG并网运行存在高频振荡和次同步振荡风险,需要合理整定其控制参数以保证其安全稳定运行。

随着电动汽车电池的大量退役和电力储能需求的增长,动力电池退役后规模化应用于储能系统成为技术趋势之一,文章从工程角度梳理了动力电池梯次利用于电力储能的全过程技术路线,包括退役电池批量筛选、系统设计及集成、工程安装调试和运维等,并对各环节中的关键技术问题予以阐述,为大容量梯次利用电池储能工程提供参考.

为实现风电友好并网,具备针对系统变化的一次调频和主动调压能力,在国网风光储电站建设风电虚拟同步发电机示范工程.目前还没有统一的新能源科技示范工程建管模式,本文对风电虚拟同步发电机建设施工进度和安全质量管控加以阐述,探索风电科技项目建设的优化管理方案.

Dynamic short-circuit current computing method（DSCCCM） is obtained based on transient simulation.The advantages of DSCCCM are pointed out by comparing the difference on grid model processing between static impedance equivalent method and DSCCCM.The on-line verification system of relay protection settings is built based on the design of DSCCCM.The true current operation state of the power grid is gained from energy management system.The short-circuit currents throughout the system are automatically calculated with the transient simulation calculation of different fault situations,achieving on-line relay setting real-time verification calculation.By comparing with the current relay settings,the security risks are pre-warned.The implementation plan and specific functions of on-line verification system of relay settings are elaborated.The application of the proposed system in North China Power Grid is introduced.

Based on practice in power system,a solution of the problem of data exchange between AEMS and EMS is given.AEMS is a distributed application system based on SOA(Service-Oriented Architecture).To realize this,we designed a data exchange platform composed of server and clients.This platform is used to solve the data exchange problem between AEM and EMS,and provide data exchange service.The data exchange between AEMS and EMS,the design and the realization of the data platform,the difficulty of data exchange and the running effect were expatiated.The system has been running steadily in Shanghai power grid since 2007 April and shows excellent performance.

A new algorithm for automatically generating power-flow diagrams is presented in this paper. Punishing Function method along with Interior Point method is adopted in the algorithm to locate stations on diagrams. Folded Line method is incorporated as well to route and connect. Diagrams generated with this new algorithm are aesthetic and practical. A software system based on this algorithm has been practically applied to the electric network as a part of AEMS system in Shanghai grid, China. The result of three applications with this algorithm, IEEE 14 Buses, IEEE 39 Buses, and the shanghai power grid are presented.