适用于福建省的大规模海上风电汇集外送输电方式研究

福建省海上风电资源丰富,近海和远海单座海上风电场区规划装机从100 MW到超过7 000 MW。该文综合海上风电规模、输送距离、海缆输送能力、经济性、实际工程经验等因素,分析海上风电的外送输电方式,重点研究柔性直流技术的适用条件;提出海上风电柔性直流换流站的并网方式、电压等级、进出线规模、电气主接线等关键方面,以及直流海缆选型;结合福建省海上风电发展规划,提出适用于福建省的大规模海上风电汇集外送的输电方式。     

半波长输电线路柔性并网研究

为了实现半波长线路并网点的高精度柔性并网,基于半波长输电线路模型、同期并网理论和统一潮流控制器(UPFC)的工作原理,将UPFC用于半波长线路的并网控制,通过在Matlab中搭建基于UPFC的半波长线路柔性并网仿真模型,对比有无柔性装置在不同并网条件下的并网特性。结果表明,基于UPFC的柔性并网装置能在不影响半波长线路输电特性的前提下,通过调节并网点参数,大大改善线路的并网特性。     

大规模风电经直流外送的区域输电能力计算

大型风电基地风电消纳的可行方案是跨区域直接送至负荷中心进行消化,由此产生大规模风电远距离输电的问题,进而对区域间最大输电能力(Total Transfer Capability,TTC)的计算提出新需求。针对大规模风电经直流外送的区域输电能力计算,结合风火打捆直流外送方式,建立了风电经直流外送的区域间TTC计算模型,并采用交直流交替迭代连续潮流算法进行求解。采用改进的IEEE 39节点系统进行测试,对大规模风电经交、直流2种外送方式下的TTC进行对比计算,并讨论了不同风电场出力情况及风火打捆比例对TTC的影响。结果表明:在既定网架结构下,需要协调考虑风火打捆比例和线路容量,在尽可能多地接纳风电的同时,使系统获得最大输电能力。     

分散式风力发电机组的电压控制

风电的分散式开发不同于大规模开发和分布式开发,由于分散风电靠近负荷中心,直接接入配电网,且不加装无功补偿调节装置SVC,配网中较大的电压波动给分散风电的并网运行带来影响。文章讨论了配网对分散风电的电压控制特点和要求,结合风电机组无功控制能力,并推导出满足配网电压调节要求的风电机组无功控制范围和对机组设备的要求。     

大规模风电经柔直并网时的系统稳态控制策略

围绕大规模风电经柔性直流输电 （voltage sourced converter based DC transmission,VSC-DC）并网时的系统稳态控制策略展开研究,并将整个系统分成风场内双馈感应式发电机（doubly-fed induction generator,DFIG）系统和风场外VSC-DC系统2个独立部分分别进行控制,提出并分析了风场内DFIG系统的稳态控制策略,包括场站内DFIG的转子侧整流器（rotor side converter,RSC）、网侧逆变器（grid- side converter,GSC）稳态控制策略,以及风场外VSC-DC系统的网侧逆变器（grid side VSC,GSVSC）、风场侧整流器（wind farm VSC,WFVSC）稳态控制策略。最后,2种典型风速工况下的仿真结果证明了所提出的系统级稳态控制策略非常有效。     

大规模风电外送系统FACTS优化配置

大规模风电的集中接入使超高压输电通道潮流频繁变化,输电网电压也剧烈波动。为此文章提出了一种基于自组织映射粒子群算法的柔性交流输电FACTS设备配置方法,以电压稳定性最佳、可用输电能力最大、投资费用最小为目标,满足电力系统约束,建立FACTS多目标优化配置模型、实现FACTS设备的优化配置。采用自组织多目标粒子群算法,在保证Pareto解集收敛性的同时,实现全局寻优。此外,以超高压等级IEEE-14节点输电系统为例,验证文章所提出的方法的有效性和先进性。分析结果表明,相较于无FACTS设备和传统粒子群优化配置方法,利用文章所提出的方法能够实现FACTS设备的优化配置,并显著提高电力系统的输电能力和电压稳定性。     

大规模风电集中接入弱电网后的无功电压紧急控制初探

针对大规模风电集中接入弱电网后的地区电网无功电压控制问题,归纳了风电机组大规模脱网事故集中暴露的问题及事后改进情况,提出了暂态电压偏移越限是风电机组具备故障穿越能力后仍然会不同程度脱网的重要原因,分析了暂态电压偏移的机理,探讨了抑制暂态电压偏移越限的无功电压紧急控制措施。     

风电机组高电压穿越技术研究

随着风电入网比例的增大,风电入网导则也逐步发展建立,入网导则的主要目的是确保风电场的入网运行不影响整个电力系统的稳定。风电场低电压穿越(LVRT)已作为热点技术被广泛关注,但风电机组风电场高电压穿越没有得到相应的重视。文章基于常见机组类型,首先介绍了风电机高电压穿越(HVRT)方面现有电网要求,给出了现有风电场高电压穿越能力要求曲线,对风电机组高电压穿越软硬件的技术方案。最后仿真证明了所提技术方案的正确性,分析了该技术方案对风机运行成本方面的可行性。     

风电机组集群协同电压控制方法

大规模风电并网后,为维持并网点电压稳定,需要实时调节每个风电机组的无功输出功率。传统集中式方法系统维度高,而分散式方法收敛速度慢。文章提出一种面向并网点电压稳定的风电机组集群协同控制方法。首先,在每个风电机组子集群中设置边缘计算装置,负责更新子集群内机组的无功输出功率以及对子集群内控制模型的降阶;然后,云端控制中心以并网点电压波动最小化为目标,更新每个子集的总无功功率输出参考值,同时更新过程考虑了信息交互过程中通信延时的影响;最后,仿真结果表明,与传统方法相比,所提方法的发电机组无功功率响应速度得到了大幅度提升。     

考虑变直流母线电压参考值的直驱风电机组高电压穿越控制策略

针对风电机组高电压脱网问题,提出了一种考虑变直流母线电压参考值与网侧无功优先控制相结合的HVRT控制策略。该策略在电压轻度骤升时,通过优化无功电流给定值,快速向故障电网注入感性无功电流;电压深度骤升时,改变直流母线电压参考值,抑制直流侧电压波动。最后,在Simulink中搭建了1.5 MW直驱永磁风电机组仿真模型,在不同电压骤升幅度下对文章所提控制策略进行验证,结果表明,该控制策略能在不同电压骤升幅度下实现机组的HVRT,且避免Chopper电路的频繁动作,提高了机组稳定运行的能力。     

含有动态无功补偿器的供电系统自动电压控制设计

在介绍自动电压控制(AVC)系统设计背景的基础上,叙述了AVC系统的结构与配置、算法与流程、关键技术与应用优势,凸显了数据采集与监控、实时控制与快速补偿、人机联系与优化调节、历史数据管理等多项新技术的整合应用。试运行表明,供电系统AVC采用一级加二级控制方式运行,保证了AVC系统的先进性和补偿功能的稳定可靠;在地区调度和终端,通过数据采集与监控装置对地调进行全面的无功电压快速调节;利用动态无功补偿器的基于直流侧电容电压控制和系统无功电流反馈控制,可以可靠、灵活地提高无功电压的控制能力。     

A decentralized voltage controller involving PV generators based on Lyapunov theory

This paper proposes a decentralized controller to coordinate the reactive power injections of PV generators in order to contribute to the voltage regulation in distribution networks. The control actions are evaluated in the real time by adopting an optimization methodology involving the sensitivity applied to the Lyapunov function. By this approach it is possible to derive an auto-adaptive algorithm that can be implemented on actual distribution network without implying additional costs for infrastructures. Computer simulations have been performed on a MV distribution system to demonstrate the effectiveness of the proposed control scheme at different operating conditions and to confirm its ability to work in the real time.     

Evaluation of operation characteristics in multiple interconnection of PV systems

A method for evaluating the operation characteristic of grid-connected PV systems in multiple interconnection was proposed and a suppression of PV electric energy which is reduced by an automatic voltage control unit was estimated using a yearly scale simulation. The automatic voltage control unit is one of the PV inverter functions. In Japan, PV systems must be provided with this function to maintain within 101 V±6 V for the standard voltage of 100 V according to the technical recommendations. The automatic control voltage unit adjusts the distribution-line voltage at a connected point using leading reactive power or active power. Especially, the adjustment of active power will cause a suppression of PV electric energy.     

浅谈输电线路运行故障分析与防治办法

作为电力系统的重要组成部分,输电线路一旦发生故障,将会引起大规模的停电事故的发生,输电线路范围广,所处的地形复杂,常会受到雷击、外力破坏、风偏放电等各类突发的运行故障,因此,深入分析输电线路的故障原因和采取针对性的防治措施显得格外重要。     

Modeling and analysis of reactive power in grid‐connected onshore and offshore DFIG‐based wind farms

The analysis of reactive power for offshore and onshore wind farms connected to the grid through high‐voltage alternating‐current transmission systems is considered in this paper. The considered wind farm is made up with doubly fed induction generators (DFIGs). Modeling and improved analysis of the effective reactive power capability of DFIGs are provided. Particularly, the optimal power‐tracking constraints and other operational variables are considered in the modeling and analysis of the DFIG reactive power capability. Reactive power requirements for both overhead and cable transmission systems are modeled and compared with each other as well as with the reactive power capability of the wind farms. Possibility of unity power factor operation suggested by the German Electricity Association (VDEW) is investigated for both types of installations. Aggregate reactive power demands on both wind farms are assessed such that the bus voltages remain within an acceptable bandwidth considering various operational limits. The reactive power settings for both types of wind farm installations are determined. In addition, the minimum capacity and reactive power settings for reactive power compensation required for cable‐based installations are determined. Several numerical examples are given to illustrate the reactive power characteristics and capability of DFIGs, performance of transmission lines and reactive power analysis for DFIG‐based grid‐connected wind farms. A summary of the main outcomes of the work presented in this paper is provided in the conclusions section. Copyright © 2012 John Wiley & Sons, Ltd.     

电力工程中溃堤洪水冲刷影响的简化判断方法

由于我国大多数河流堤防标准较低,工程中常需考虑溃堤洪水对临河线路杆塔的冲刷影响,但溃堤洪水冲刷计算公式参数较多、计算复杂,不利于工程现场对冲刷影响的快速判断。针对这种现状,基于溃堤洪水冲刷原理,总结出一套溃堤洪水冲刷影响的简化判断方法,通过简化相关计算条件,并以工程中常见的堤高及土壤粒径组合,计算出相应的冲刷影响值,并将结果制表、成图,工程技术人员现场踏勘时可根据堤高及土壤粒径条件快速定性判断溃堤洪水对线路工程的影响范围及深度,有助于输电线路工程跨河及沿河方案的选择。     

Reactive power management and control of distant large-scale grid-connected offshore wind power farms

Reactive power management and control of distant large-scale offshore wind power farms connected to the grid through high-voltage alternating current (HVAC) transmission cable are presented in this paper. The choice of the transmission option is based on the capacity of the considered wind farm (WF) and the distance to the onshore grid connection point. The WF is made up of identical doubly-fed induction generators (DFIGs). Modelling and improved analysis of the effective reactive power capability of DFIGs as affected by various operational constraints are provided. In addition, modelling and analysis of the reactive power demands, balance, and control are presented. The minimum capacity and reactive power settings for reactive power compensation required for the system are determined. Possibility of unity power factor operation suggested by the German electricity association (VDEW) is investigated. A summary of the main outcomes of the work presented in this paper is provided in the conclusions section.     

±800 kV特高压直流输电线路电磁环境 参数控制指标研究

采用长距离、大容量输电时,特高压直流输电能够有效地节省线路走廊、有助于改善网络结构,实现大范围的资源优化配置。总结了国内外研究成果,结合我国实际情况,就如何规范±800kV特高压直流输电线路的环境行为,围绕电场、磁场、无线电干扰和可听噪声等电磁环境参数进行研究,提出了环境参数的控制指标：以30kVhn作为直流输电线路下方最大地面合成场强的控制指标;25kV／m作为邻近民房的最大合成场强的控制指标;以好天气下58dB（μV／m）为距极导线投影外侧20m处0．5MHz的无线电干扰电平的控制指标;L50=50dB（A）为线路可听噪声设计控制指标,人口密集区以L50=45dB（A）校核。     

电力输电线路安全运行的探讨

针对我国目前电力网运行现状,剖析电力输电线路安全运行中存在的隐患因素。提出对电力输电线路安全运行的方法和对策,确保电力系统输电线路安全运行的可靠性。确保人民生活、生产用电供电质量,促进整个国民经济的飞跃发展。     

Reactive power market management considering voltage control area reserve and system security

This paper presents a new algorithm to optimize reactive power procurement through commercial transactions considering system voltage security. The proposed algorithm minimizes reactive power provision and transmission loss costs in addition to maximizing system voltage security margin through a multiobjective function. In order to maintain the voltage profile of power system during sever contingencies or due to load uncertainty, all voltage control areas (VCA) of the system are detected and then optimal reactive power reserve is provided for each VCA during the market settlement. A four-stage multiobjective mathematical programming method is proposed to settle the reactive power market. The proposed algorithm has been applied on IEEE-RTS test system. The simulation results show the effectiveness of the proposed algorithm for reactive power market management.