DISOPE distributed model predictive control of cascade systems with network communication

A novel distributed model predictive control scheme based on dynamic integrated system optimization and parameter estimation （DISOPE） was proposed for nonlinear cascade systems under network environment. Under the distributed control structure, online optimization of the cascade system was composed of several cascaded agents that can cooperate and exchange information via network communication. By iterating on modified distributed linear optimal control problems on the basis of estimating parameters at every iteration the correct optimal control action of the nonlinear model predictive control problem of the cascade system could be obtained, assuming that the algorithm was convergent. This approach avoids solving the complex nonlinear optimization problem and significantly reduces the computational burden. The simulation results of the fossil fuel power unit are illustrated to verify the effectiveness and practicability of the proposed algorithm.

Stability Analysis and Control of DC Distribution System with Electric Vehicles

The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable oscillations.The current interpretation of the oscillation mechanism has not been unified.Firstly,this paper established the complete statespace model of the distribution system consisting of a large number of electric vehicles,characteristic equation of the distribution network system is derived by establishing a state-space model,and simplified reduced-order equations describing the low-frequency oscillation and the high-frequency oscillation are obtained.Secondly,based on eigenvalue analysis,the oscillation modes and the influence of the key system parameters on the oscillation mode are studied.Besides,impacts of key factors,such as distribution network connection topology and number of dynamic loads,have been discussed to suppress oscillatory instability caused by inappropriate design or dynamic interactions.Finally,using the DC distribution example system,through model calculation and time-domain simulation analysis,the correctness of the aforementioned analysis is verified.

Distributed Periodic Event-Triggered Optimal Control of DC Microgrids Based on Virtual Incremental Cost

This article presents a distributed periodic eventtriggered(PET)optimal control scheme to achieve generation cost minimization and average bus voltage regulation in DC microgrids.In order to accommodate the generation constraints of the distributed generators(DGs),a virtual incremental cost is firstly designed,based on which an optimality condition is derived to facilitate the control design.To meet the discrete-time(DT)nature of modern control systems,the optimal controller is directly developed in the DT domain.Afterward,to reduce the communication requirement among the controllers,a distributed event-triggered mechanism is introduced for the DT optimal controller.The event-triggered condition is detected periodically and therefore naturally avoids the Zeno phenomenon.The closed-loop system stability is proved by the Lyapunov synthesis for switched systems.The generation cost minimization and average bus voltage regulation are obtained at the equilibrium point.Finally,switch-level microgrid simulations validate the performance of the proposed optimal controller.

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

Research on Distributed Cooperative Control Strategy of Microgrid Hybrid Energy Storage Based on Adaptive Event Triggering

Distributed collaborative control strategies for microgrids often use periodic time to trigger communication,which is likely to enhance the burden of communication and increase the frequency of controller updates,leading to greater waste of communication resources.In response to this problem,a distributed cooperative control strategy triggered by an adaptive event is proposed.By introducing an adaptive event triggering mechanism in the distributed controller,the triggering parameters are dynamically adjusted so that the distributed controller can communicate only at a certain time,the communication pressure is reduced,and the DC bus voltage deviation is effectively reduced,at the same time,the accuracy of power distribution is improved.The MATLAB/Simulink modeling and simulation results prove the correctness and effectiveness of the proposed control strategy.

Operation Control Method of Relay Protection in Flexible DC Distribution Network Compatible with Distributed Power Supply

A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.

Fuzzy Droop Control for SOC Balance and Stability Analysis of DC Microgrid with Distributed Energy Storage Systems

The unbalanced state of charge(SOC)of distributed energy storage systems(DESSs)in autonomous DC microgrid causes energy storage units(ESUs)to terminate operation due to overcharge or overdischarge,which severely affects the power quality.In this paper,a fuzzy droop control for SOC balance and stability analysis of DC microgrid with DESSs is proposed to achieve SOC balance in ESUs while maintaining a stable DC bus voltage.First,the charge and discharge modes of ESUs are determined based on the power supply requirements of the DC microgrid.One-dimensional fuzzy logic is then applied to establish the relationship between SOC and the droop coefficient R,in the aforementioned two modes.In addition,when integrated with voltage-current double closed-loop control,SOC balance in different ESUs is realized.To improve the balance speed and precision,an exponential acceleration factor is added to the input variable of the fuzzy controller.Finally,based on the average model of converter,the system-level stability of microgrid is analyzed.MATLAB/Simulink simulation results verify the effectiveness and rationality of the proposed method.

DCS控制器中电表接触传感器计量误差检测方法

由于DCS控制器中电表传感器在计量检测过程中,传统的B-MAC-DCS协议能耗和丢包率较高,无法缓解汇聚节点的漏斗效应,导致在远程抄表过程中传感器计量误差增大。提出一种机械电表接触传感器计量误差检测方法。采用小波基函数对DCS控制器中的接触传感器计量数据抗干扰处理,并通过动态选取阈值的方法,对经过小波变换后的数据去除噪声。使用低功耗自适应集簇分层型(low energy adaptive clustering hierarchy,LEACH)协议分簇代替传统的B-MAC协议;根据簇内监测值,引入阈值分析方法获取传感器计量指标,并将其作为判定依据进行误差检测,根据计量指标的变化情况判断是否存在计量误差。实验结果表明,所提方法可以准确且有效检测出机械电表接触传感器计量误差,解决DCS中机械电表的运行隐患问题。

基于CNN的OCR技术在核电厂DCS系统测试中的应用和实现

核电厂分布式控制系统(DCS)的输入/输出模块在运行期间,随着电子器件性能下降以及时漂的影响,需要定期进行进度复测和校准。针对传统的DCS输入/输出通道测试覆盖率不足,测试效率低及人因问题,本文提出一种基于卷积神经网络(CNN)的光学字符识别(OCR)技术应用在DCS系统的在线测试方法。通过模拟设备和视频采集设备完成画面的自动切换,并读取画面信息,截取特定画面后对其图像预处理,再使用OCR识别模型识别画面内容,将得到的识别结果与期望值进行比较判断,从而实现自动化测试。测试结果表明,通过CNN训练后,显控设备画面字符识别率能达到100%,该方法可以突破设备厂家的专有通信协议的壁垒,可有效降低操作员的人因失误,提升测试效率和核电厂的经济性。

Key technologies for medium and low voltage DC distribution system

Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operation of the AC/DC interconnected grid.This paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries,and then elaborate status of under-construction medium and low voltage DC distribution system project cases in China.Based on these project cases,this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies,equipment,operation control technologies and DC fault protections,in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related projects.Finally,this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system,which can provide reference for the research of medium and low voltage DC distribution system.

新一代的分散控制系统——PROCONTROL P

本文介绍ＡＢＢ向电站控制最新推出的ＰＲＯＣＯＮＴＲＯＬＰ分散控制系统，着重分析系统在适应电站过程控制、控制系统组织和实现等方面的特点。

Optimization of Control Loops and Operating Parameters for Three-Phase Separators Used in Oilfield Central Processing Facilities

In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.

DCS在电除尘系统自动控制的应用研究

传统的电除尘器自动控制系统采用可编程逻辑控制器(PLC)控制,其逻辑复杂、可读性差、可维护性低。PLC系统无法与主控系统完成一体化,导致工艺上的割裂,额外地增加了运维成本。本文提出了一种基于分散控制系统(DCS)的电除尘器自动控制方案。

DCS系统在燃气输配控制中的应用研究进展

为探讨DCS系统在燃气输配控制中的应用,并分析其通过实时监测和控制关键参数来提高系统效率和安全性的能力。采用DCS系统对天然气输配网络进行实时监测和控制。通过对天然气管道的压力、温度、流量等关键参数进行实时采集和调节,确保系统运行在稳定、高效的状态。同时,利用DCS系统的强大数据采集、处理和分析能力,对输配过程中的故障和异常情况进行快速诊断和处理,以提高故障排除的效率。此外,DCS系统还支持网络化和远程控制功能,实现对不同地理位置的天然气输配网络的集中监管和管理。结果表明:通过应用DCS系统,燃气输配控制实现了高效、准确和可靠的管理。实时监测和调节关键参数确保了系统运行的安全性和稳定性。快速诊断和处理故障和异常情况提高了故障排除的效率。网络化和远程控制功能实现了对不同地理位置的天然气输配网络的统一监管和管理,提高了管理效率。DCS系统在燃气输配控制中的应用具有重要意义和潜力。通过实时监测和控制关键参数,可以提高系统的效率和安全性。然而,该系统的应用也面临一些挑战,如高成本、技术难题以及应急处理等方面的问题。因此,需要进一步的技术研发和应用实践来不断提升DCS系统的性能和可靠性,以更好地满足燃气输配控制的需求。

Siemens DP／PA Link模块在ABB Control Builder F平台中的组态

在现场总线控制系统中，现场仪表可通过Profibus—DP／PALink模块挂接到Profibus总线上。本文详细介绍在ABB的Freelance 800 F DCS系统及其Control Builder F软件平台中，如阿通过西门子的Siemens DP／PA Link模块来组态PA仪表的步骤。

DCS网络安全维护在电力系统监控中的关键技术研究与应用

随着信息技术的不断发展和普及,电力系统监控与控制逐渐向数字化、自动化以及智能化方向发展。同时,网络安全面临的挑战日益严峻。电力系统作为关乎国家经济安全和民生福祉的重要基础设施,其安全稳定运行对于社会的正常运转至关重要。分布式控制系统(Distributed Control System,DCS)作为电力系统监控与控制的核心系统,承担着实时监测、数据采集以及远程控制等重要任务,其安全性直接关系到整个电力系统的安全和稳定运行。文章从DCS网络安全维护的角度出发,探讨在电力系统监控与控制中的关键技术和应用策略。

火电厂热工自动化DCS

在自动化技术与先进控制系统的支持下,使用火电厂热工自动化分散控制系统(Distributed Control System,DCS)可监测、控制和调节火电厂热工过程,优化生产过程。基于对DCS的深入理解,利用其包含的数据采集系统(Data Acquisition System,DAS)、管理控制系统(Monitoring and Control System,MCS)、监控控制系统(Supervisory Control System,SCS)、数字电液调节系统(Digital Electro-Hydraulic Control System,DEH)、炉膛安全监控系统(Furnace Safeguard Supervisory System,FSSS),实现智能化控制热工过程。然而,在发电过程中,火电厂热工自动化DCS易受辐射及电源引入等方面的干扰,这在一定程度制约着热工自动化控制效果,因此需从源头、安装、应用等方面控制干扰,以提升系统稳定性。

DCS安全通信网络搭建探析

随着信息技术的飞速发展,分布式控制系统(Distributed Control System,DCS)已成为多种工业过程中不可或缺的组成部分。但随之而来的是日益严峻的网络安全挑战。本研究先分析DCS安全通信网络系统的架构设计,接着介绍一种新的基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)技术的安全通信网络实现方案,旨在为DCS安全通信网络的搭建提供理论依据和技术指导,对促进工业环境中的网络安全具有重要意义。

基于SDN技术的火电厂DCS后台控制系统优化研究

为解决传统分散控制系统(Distributed Control System,DCS)存在的响应延迟、故障恢复慢以及安全防护能力不足等问题,文章基于软件定义网络(Software Defined Networking,SDN)技术设计并实现了火电厂DCS后台控制系统。通过介绍SDN技术与火电厂DCS系统,设计基于SDN技术的DCS系统架构,重点阐述实时控制反馈模块、故障检测恢复模块以及网络安全防护模块的具体设计与功能实现。通过实验分析,验证了基于SDN技术的优化方案在提高系统响应速度、增强故障恢复能力以及提升网络安全性方面的显著效果。

Distributed DC-Bus Signaling Control of Photovoltaic Systems in Islanded DC Microgrid

The stability of an islanded DC microgrid(DCMG)is highly dependent on the presence and performance of the backup energy storage system(BESS),due to the lack of main grid support.This condition makes the DCMG vulnerable to the critical situation of absence of the BESS,which could be caused by a fault or being fully charged or flat.This paper presents an enhanced distributed DC-bus signaling control strategy for converters of photovoltaic systems(PVs)to make the islanded DCMG less dependent on the BESS.Unlike a conventional control approach that utilizes PVs to operate in maximum power point tracking(MPPT)mode and the BESS solely regulating DC-bus voltage,the proposed control method maintains DC-bus voltage via intelligently managing output powers of the PVs.The proposed control method continuously monitors DC-bus voltage and regulates the output powers of all the PVs via switching between MPPT mode and voltage regulating mode.Accordingly,if the DC-bus voltage level is less than a predefined maximum level,the PVs work in MPPT mode;otherwise,the PVs work in voltage regulating mode to maintain DC-bus voltage at an acceptable range.Such switching between MPPT and voltage regulating control operations results in protecting the DCMG from unavoidable shutdowns conventionally necessary during the absence of the BESS unit.Moreover,the proposed control method reduces oscillations on the DC-bus voltage during existence of the BESS.The performance and effectiveness of the proposed control strategy are validated through different case studies in MATLAB/Simulink.