风电介入下的多区域互联电力系统分布式经济模型预测负荷频率控制

针对风电介入下的多区域互联电力系统,提出一种分布式经济模型预测负荷频率控制策略.通过将大规模互联电力系统分解成若干个动态耦合的子系统,这些子系统能够利用网络交流并共享信息,使得各区域的控制器实现各自优化问题的求解.同时,在满足状态约束和控制输入约束的前提下,遵循传统火力发电优先、风力发电配合的原则,通过在线求解优化问题,实现风电介入下的多区域互联电力系统的负荷频率控制.为了提高系统整体运行经济性,所提出的分布式经济模型预测控制器将负荷调频成本、燃料消耗成本以及风力发电成本等经济性指标考虑在内.仿真结果表明,在阶跃负荷扰动下,所设计的控制器不仅可以满足调频要求,在降低计算负担和提高经济性能方面也具有一定优势.     

基于AGC的光伏电站一次调频控制

逆变器调节速度快,且利用光伏电站的调频能力可降低常规调频备用容量,光伏电站深入参与电网一次调频将是一种很好的选择。基于此,本文在光伏电站自动发电控制（AGC）系统基础上增加光伏电站有功-频率下垂控制特性,使光伏电站在无需额外硬件增加或改造基础上实现AGC和一次调频功能一体化集成;其次,增加一次调频和AGC配合策略,实现二者无缝配合;最后,针对有功功率跟踪能力的不足对有功分配策略进行改进,提高了有功功率控制精度,提升了调频贡献能力。经过西北电网组织的新能源电站快速调频试验的验证,基于光伏电站自动发电控制系统的光伏电站一次调频控制具备较好的响应速度和调频贡献能力,能够为电网频率稳定提供支撑作用。     

励磁调差单元对发电机频率响应特性的影响分析

发电机的频率响应特性是电力系统稳定器的参数整定的重要依据,为优化参数整定,维护电力系统安全稳定运行,对引入调差单元的发电机的频率响应特性进行研究.通过分析负载电流极性、调差系数及调差极性改变时励磁系统测量电压的变化特性,采用戴维南电路对自动励磁的作用进行等效研究,并对不同调差方式下发电机的频率响应特性进行了仿真实验.理论分析与仿真结果表明,调差单元引入后测量电压的改变会影响同一频率下发电机机端电压的幅值和相位,且调差单元在低频段对发电机频率响应特性的影响较为明显,因此具有一定的工程应用价值.     

基于多源数据的电网一次调频能力平行计算研究

为解决电网一次调频性能难以估计的问题, 本文提出了基于多源数据的电网一次调频性能平行计算平台. 通过采集整合OMS (Operations management system)、WAMS (Wide area measurement system)、SCADA (Supervisory control and data acquisition)等系统的各类型一次调频数据, 以极大似然估计、数值拟合等方法构建机组一次调频性能功频图谱. 采用均方差分析建立电网一次调频性能数学模型, 基于并网运行机组的一次调频性能功频图谱, 估算出当前电网的实际一次调频性能. 算例计算表明, 本文所提出的计算方法能够有效兼顾机组类型的静态特性和运行工况的动态特性, 并以平行执行方式完成人工估算系统与实际电力系统的滚动优化, 实现了电网一次调频性能的在线全面估计, 为电网频率管理与控制提供数据决策支持.     

应用于原动系统的励磁调节器建模与仿真

数字式励磁调节器应用在电力系统动态模拟实验室的原动系统中,根据原动励磁系统的实际运行情况建立数字式励磁调节器的模型,主要由采样单元、数据处理单元、控制单元等模型组成.同时考虑了并网调差环节,在Matlab/simulink环境下对励磁调节器模型进行仿真,仿真结果表明发电机的起励、阶跃、强励响应等性能均满足系统要求,对同步发电机模拟励磁系统具有良好的控制效果.     

基于下垂控制的电力电子变压器并联运行策略

电力电子变压器(PET)的并联运行对提高电力系统供电的可靠性和稳定性具有重要的意义.为了解决并联系统的环流和负荷均分的问题,将下垂控制理论引入电力电子变压器并联的控制策略中,传统的下垂控制无法适用于线路阻感比较大的低压电网.提出通过控制参数的设计使系统等效输出阻抗呈感性,可以改善系统的阻感比,从而满足下垂控制的需要,同时提高系统运行稳定性.在Matlab/Simulink中建立了两台PET的并联系统并进行仿真研究,结果表明,该控制策略可以在保持输出电压幅值和频率稳定的前提下很好地抑制并联环流,并实现负荷的合理分配,且具有良好的动态性能.     

核电厂汽轮机一次调频设计方案与应用研究

电网频率是保证电能质量的重要指标。随着用电结构变化导致负荷峰谷差逐步增大,电网对并网机组一次调频的要求也越来越高。目前,国内核电机组装机容量日益增加,其一次调频性能对电网和机组安全影响较大,如何设计核电机组的一次调频方案及设置合理的一次调频参数,并保证核电机组按电网要求投入一次调频功能,关系着整个核电机组的安全与稳定运行。在分析发电机组一次调频特性、研究核电机组带一次调频的转速负荷无扰切换控制原理的基础上,提出了适用于核电机组的一次调频及频率限制功能的逻辑设计方案,并根据堆机匹配的控制要求优化了一次调频参数。在汽轮机控制系统模拟机上,对一次调频方案进行仿真验证。结果表明,一次调频方案可以快速响应电网频率变化并保证机组安全稳定运行,满足电网的一次调频要求和汽轮机的控制要求,对后续核电机组参与电网调频调峰的方案设计、现场调试及运行具有重要的参考价值和理论指导意义。     

考虑系统频率响应特征的配电网综合优化规划

以风电为代表的新能源大规模并入电力系统,其输入给电网能力的不可预测性给电力系统的有功功率平衡以及频率控制带来了严重影响.基于此,提出一种考虑系统频率响应的鲁棒区间风电并网优化调度模型.该模型以发电成本以及风电场弃负荷惩罚成本建立目标函数,通过计算鲁棒区间并制定最佳的发电方案,能够有效降低系统的成本以及系统频率控制.同时...     

基于灵敏度分析的新能源电站无功电压自动控制方法

无功电压的大小会直接影响电网中电能的利用效率,因此有必要开展无功电压自动控制研究。随着新能源技术的快速发展,我国电力系统越来越向智能化、数字化、网联化方向发展。无功控制作为新能源发电的重要组成部分,是防止电网过负荷和电压升高的有效措施,也是实现大规模新能源应用的基础。结合新能源电站无功原理与控制策略,提出了新型高效无功电压自动智能控制器结构及灵敏度分析方法,以及基于逻辑判断、灵敏度计算等算法进行参数分析与参数优化的无功控制策略体系。结果表明：采用智能化控制后,系统运行可靠性得到明显提高;采用基于逻辑判断、灵敏度计算模式可提高电压源故障检测精度;系统响应速度快,输出信息准确;可以实现大范围、长时间运行过程中的全过程自动动态调节、故障快速切除。     

电动助力转向系统的模糊自适应PID控制

研究实时跟踪助力转向系统,针对汽车电动助力转向系统(EPS)控制的可靠性和稳定性要求,由于正常运行电机转向柱和轴运动均有滞后稳定性差的问题,在对EPS的结构和动力学性能分析的基础上,建立EPS系统仿真模型,提出模糊自适应PID控制策略.模糊自适应PID控制在系统动态过程中能实时改变PID参数,使系统不同的状态对应不同的PID参数,克服了控制参数固定不变无法实时控制EPS系统动态响应特性.仿真结果表明,在EPS中模糊自适应PID控制比常规PID控制具有更好的稳定性和可靠性,完全满足EPS的控制系统快速特性的要求.     

基于CAN总线的多伺服电机同步控制

根据印刷机械的工艺特点,针对传统以机械长轴为动力源的印刷机同步系统,设计了基于CAN现场总线的多伺服电机同步控制系统方案,提出了上位机同步运动数据的产生机制,和上位机、驱动器之间的时钟同步机制和同步接口协议,并得以验证。     

Distributed control and energy storage requirements of networked Dc microgrids

Microgrids are a key technology to help improve the reliability of electric power systems and increase the integration of renewable energy sources. Interconnection and networking of smaller microgrids into larger systems have potential for even further improvements. This paper presents a novel approach to a distributed droop control and energy storage in networked dc microgrids. Distributed control is necessary to prevent single points of failure along with flexibility and adaptability to changing energy resources. The results show that systems with random sources and fast update rates, a networked microgrid structure can minimize required energy storage requirements.     

低压微电网下垂控制策略研究

在孤岛模式时通过把逆变器等效输出阻抗设计成近似感性的前期条件下采用频率/有功、电压/无功的传统下垂控制法,但由于输出的无功与线路阻抗有关而各逆变器位置分散使连接线路阻抗存在差异,故难以实现无功功率的合理分配。本文分析传统下垂控制原理,并通过虚拟电抗法把逆变器的等效输出阻抗设计成近似感性,在此基础上采用一种改进下垂控制策略。该策略通过调节下垂控制中的参考电压来大致补偿线路阻抗差异上的电压降落,同时配合一个动态下垂系数来代替传统的固定下垂系数动态调节输出的无功功率,从而改善微电网无功功率输出的分配精度抑制系统环流。最后通过MATLAB/Simulink搭建两台逆变器并联运行模型并采用传统下垂控制与改进下垂控制相比较的方法验证改进控制策略的可行性。     

Hybrid modeling of central receiver solar power plants

With the forecast exhaustion of fossil fuels, governments are promoting renewable power plants as a viable alternative for electricity generation. One of the disadvantages of this kind of power generation facilities is the need to have a backup fuel, because the primary renewable resource is uncontrollable and discontinuous. From a modeling point of view, a power station with more than one source of supply changes its dynamical behavior according to Boolean events, thus mixing continuous and discrete dynamics in the system. The main contribution of this work is the modeling of a renewable power plant with two energy sources using a Mixed Logical Dynamical (MLD) representation, which is a modeling tool for the representation of hybrid systems. The advantages of using this modeling approach are discussed in the paper.     

Distributed Virtual Inertia Based Control of Multiple Photovoltaic Systems in Autonomous Microgrid

The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system. Since an autonomous renewable microgrid usually has much smaller inertia, the control system must be very fast and accurate to fight against the small inertia and uncertainties. To reduce the demanding requirements on control, this paper proposes to increase the inertia of photovoltaic (PV) system through inertia emulation. The inertia emulation is realized by controlling the charging/discharging of the direct current (DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary. By well designing the inertia, the DC-link capacitor parameters and the control range, the negative impact of inertia emulation on energy efficiency can be reduced. The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements. Simulation studies demonstrate the effectiveness of the proposed solution.      

A reactive scheduling and control framework for integration of renewable energy sources with a reformer-based fuel cell system and an energy storage device

The main technological barrier in relying solely on renewable energy resources is that the sources such as wind and solar are highly intermittent in availability and result in uncertainty in demand satisfaction. This paper focuses on the integration of these uncertain renewable energy sources along with relatively deterministic energy sources such as reformer based fuel cell and battery. The power mix scenario between these multiple renewable energy sources along with the reformer based fuel cell system, coupled with an energy storage option is envisaged in this paper to ensure undisrupted power supply, to combat the possible intermittent nature of these renewable sources. An appropriate scheduling layer which provides a detailed plan of the optimum contribution of the various available power sources is considered over one week (7 days) duration. A model predictive control (MPC) scheme is deployed at the lower level control layer that receives a measurement of the possible fluctuations or uncertainties in the renewable power sources and maintains a smooth operation of the power generation system through appropriate decisions on generation via the reformer based fuel cell or by exploiting the battery storage, to ensure a delay-free delivery of power to the external load. During real-time operation of the plant, due to the uncertainties in the contribution from solar and wind sources, the power demanded from the fuel cell and the battery is varied accordingly by the MPC layer to meet the overall power demand. The performance of the designed MPC to maintain a smooth delivery of power in both the absence and presence of uncertainties in the renewable energy sources, with and without a reactive feedback between the scheduling and control layers, is illustrated using case studies.     

Multi agent system: concepts,platforms and applications in power systems

The power system is presently experiencing vital changes: it is advancing from a centralized structure to a decentralized one, primarily because of the enormous advancement of distributed renewable energy sources, so future power system obliges new control strategies. These systems must have the capacity to withstand new requirements, for example, the exceedingly disseminated nature, the irregularity of renewable energy sources and the restricted data transfer capacity for communications. Multi agent systems (MAS) have attributes that meet these prerequisites. A certain degree of distributed or collective intelligence can be accomplished through the connection of these agents with one another, participating or contending to achieve their objectives. This paper introduces outline of the fundamental ideas of MAS and its different platforms. Also, it provides a comprehensive survey on the power system applications in which MAS technique has been applied. For each power system application, technical details are also discussed.     

高空风电系统的优化控制研究进展与挑战

为了实现“碳达峰,碳中和”的战略目标,我国将持续推动可再生能源的高比例发展,构建以新能源为主的新型电力系统.作为可再生的清洁源,风能的开发和利用已成为研究的重要方向.研究表明远离地面的高空中风速更加强劲并且更均匀,风向也更稳定,因此,风力发电的进一步突破可以通过用风筝捕获高空风能来实现.为了确保高空风能系统安全、经济、高效地运行,对其控制系统设计的要求极高.本文阐述了国际上几种主流高空风电技术的发电原理、发展进程以及现状.通过对典型的Yo-Yo式结构进行动力学建模,分析了各类非线性控制技术的原理和特点,具体描述了非线性模型预测控制原理和轨迹跟踪控制的仿真结果.总结了未来高空风能控制技术面临的控制算法计算量大,控制系统可靠性研究缺乏以及智能化水平不高等关键问题.