Study of Micro Grid Safety &Protection Strategies with Control System Infrastructures

Microgrids have been proposed in order to improve reliability and stability of electrical system and to ensure power quality of grid. Microgrid consists of low voltage distribution systems with distributed energy resources, such as wind turbine and photovoltaic power systems, together with storage devices. It is essential to protect a micro grid in both the grid-connected and the islanded mode of operation against all different types of faults. This paper describes micro grid protection and safety concept with central control and monitoring unit where multifunctional intelligent digital relay could be used. This central control & monitoring infrastructure is used for adaptive relay settings strategy for micro grid protection. Also operational safety design concept and fault mitigation technique is proposed to ensure confidence in protection system.

Combining Market-Based Control with Distribution Grid Constraints when Coordinating Electric Vehicle Charging

The charging of electric vehicles(EVs) impacts the distribution grid, and its cost depends on the price of electricity when charging. An aggregator that is responsible for a large fleet of EVs can use a market-based control algorithm to coordinate the charging of these vehicles, in order to minimize the costs. In such an optimization, the operational parameters of the distribution grid, to which the EVs are connected, are not considered. This can lead to violations of the technical constraints of the grid(e.g., undervoltage, phase unbalances); for example, because many vehicles start charging simultaneously when the price is low. An optimization that simultaneously takes the economic and technical aspects into account is complex, because it has to combine time-driven control at the market level with eventdriven control at the operational level. Diff erent case studies investigate under which circumstances the market-based control, which coordinates EV charging, conflicts with the operational constraints of the distribution grid. Especially in weak grids, phase unbalance and voltage issues arise with a high share of EVs. A low-level voltage droop controller at the charging point of the EV can be used to avoid many grid constraint violations, by reducing the charge power if the local voltage is too low. While this action implies a deviation from the cost-optimal operating point, it is shown that this has a very limited impact on the business case of an aggregator, and is able to comply with the technical distribution grid constraints, even in weak distribution grids with many EVs.

Trends and Overview Regarding the Involvement of Micro-Grids in Modern Power Systems

Customer satisfaction and participation in utility supply packages is the first and foremost factor in the success of any supplying agency whether wholesale or retail dealer. The paper presents the concept of major prospects of non- autonomous micro-grids installed in a certain locality. The article shows the basic background that is required for the installment of micro grid in a particular area and discusses the primary factors or pre-requisites that are required for the existence and operation of micro-grids. It elaborate the major profitable applications and benefits that developing and developed states get by using micro-grids in an area where utility grid is already functioning .It also explains the basic improvement in the quality of supply from micro grid after its installment. It also throws light on afterwards impact on society with this system, such impacts include reliability, tariff rates, economics etc. The article discusses micro-grids as the future of modern power systems. This paper shows significance of modernization by latest topologies in power systems and its effect that will come afterwards.

Distributed Design of Approximately Optimal Controller for Identical Discrete-Time Multi-Agent Systems

This paper considers the distributed control of the LQR problem for discrete-time multiagent systems.Distributed controllers are designed based on the solutions of centralized optimal control and the topological structure of the systems.Under mild conditions,it is shown that the distributed controller can approximate to the centralized optimal controller.Then the states of the closed-loop systems of the distributed control exponentially converge to the states of the closed-loop systems of the centralized optimal control.Some examples are given to show effectiveness of the proposed results.

Pressure distribution of combining center cavity slipper for axial piston pump

In order to improve lubricating characteristics of slippers in an axial piston pump, the combining center cavity slipper approach was proposed based on slipper shape and moving characteristic. The cylindrical coordinate was used in the lubricant area and mesh was made. The blockweight approach was implemented to deal with non-coincidence of mesh and shallow recess border in numerical method. The finite control volume method was applied in calculating pressure distribution. The flow conservation equation and film thickness model were resolved through Gauss-Siedel relaxation iteration. The calculation and analysis results indicate that compared to the slipper （1） slip- per pressure distribution is improved; （2） hydrodynamic pressure of the combining slipper is greatly increased; （3） inclining degree is greatly reduced; （4） negative pressure in lubricant film disappear. So the combining center cavity slipper is lubricated better.

有人直升机/无人机协同编队指挥控制体系设计

针对有人/无人机(Manned Aerial Vehicle/Unmanned Aerial Vehicle,MAV/UAV)编队协同作战的发展趋势,开展了MAV/UAV协同编队指挥控制系统设计研究。分析了MAV/UAV的协同作战样式对指挥控制系统的需求。对比了目前集中式、分布式和有限集中式3种指挥控制结构,兼顾UAV智能化水平和数据链路状态,设计了基于集散式的指挥控制系统,该系统集合了集中式和分布式的特点,在协同编队指挥控制中具备通信要求适中、可扩展性高和鲁棒性强等优势。

计及多光储一体机的配电网电压优化控制策略

大规模分布式光伏接入配电网易造成并网点电压越限,威胁配电网安全稳定运行。面向计及多光储一体机的配电网提出一种集中式优化与分布式实时控制相结合的电压优化控制策略。首先建立配电网集中式滚动优化模型,制定各光储下个时段的电压和功率参考;然后提出基于电压灵敏系数的分布式电压实时控制方法,制定就地无功下垂曲线、分布式无功电压支撑和就地有功功率控制逻辑;最后通过IEEE33节点算例验证所提控制策略的可行性和有效性。所提电压控制策略能够有效解决电压越限问题,并具备源荷功率随机波动下的自适应调压能力。

基于油藏化学驱能耗分配原理的理想流度控制型驱油剂研究Ⅰ:聚/表二元复合驱油体系的渗流阻力调控机理及应用

针对驱油剂的深部流度控制能力与近井地带注入性之间的矛盾,提出了理想流度控制型驱油剂应满足低黏度配制/输送、近井地带低吸附量长期稳定注入和低浓度产出液的技术要求,同时,在渗流过程中能够在储层深部不同位置建立多级渗流阻力峰值,并且前缘后驱替相渗流阻力应始终保持在较低水平。基于固/液界面吸附作用与分子间相互作用的协同效应,设计了在渗流过程中具备动态改变体系组成和微观溶液结构,从而改变其渗流阻力特征的疏水缔合聚合物/阴离子型表面活性剂二元体系。相较于HP-1(1500 mg/L),表观黏度相近、组成不同的二元体系HP-1(1500 mg/L)/SDSB(150 mg/L)和HP-1(1500 mg/L)/SDSB(200 mg/L),在段塞注入及其后续水驱过程中可以在多孔介质的中、后部构建数值更高、空间分布更优的动态渗流阻力,说明二元体系具备运移增黏特征和延迟突破特征,其前缘的流度控制能力更强,并且渗流阻力在储层的空间分布更合理,从而延长了段塞整体突破时间,有利于提高波及体积和驱油效率。在相对稠油、强非均质性和水驱含水率为80%的渤海某油田油藏条件下,采用基本相同剂量、相近成本的化学剂工业产品进行的驱油实验表明:二元体系后续水驱突破之前驱油剂段塞渗流阻力的空间动态分布特征是影响驱油效率的关键因素,二元体系(AP-P4(1400 mg/L)/ZX-27(300 mg/L),黏度为6.4 mPa·s)比疏水缔合聚合物AP-P4(1750 mg/L,黏度为62.9 mPa·s)多提高10%的原油采收率。

大型泵站群自主可控远程集控系统研究与设计

以自主可控、维护简便、实时性、可用性为导向,研究并设计大型泵站群集控系统。集控系统设计基于分布式架构的数据库体系,进行多机冗余管理、权限管理,采用远动通讯协议的网络通信架构,高性能实时数据与历史数据的存储与访问机制,利用平台消息总线、服务总线实现基础集控功能,同时支持图形展示、报表展示、事件及报警、泵站联合调度及可视化应用等各类业务的互通互融,为大型泵站群安全稳定运行提供有力支撑。

Lane-change path planning and control method for self-driving articulated trucks

Purpose–This study aims to develop an automatic lane-change mechanism on highways for self-driving articulated trucks to improve traffic safety.Design/methodology/approach–The authors proposed a novel safety lane-change path planning and tracking control method for articulated vehicles.A double-Gaussian distribution was introduced to deduce the lane-change trajectories of tractor and trailer coupling characteristics of intelligent vehicles and roads.With different steering and braking maneuvers,minimum safe distances were modeled and calculated.Considering safety and ergonomics,the authors invested multilevel self-driving modes that serve as the basis of decision-making for vehicle lane-change.Furthermore,a combined controller was designed by feedback linearization and single-point preview optimization to ensure the path tracking and robust stability.Specialized hardware in the loop simulation platform was built to verify the effectiveness of the designed method.Findings–The numerical simulation results demonstrated the path-planning model feasibility and controller-combined decision mechanism effectiveness to self-driving trucks.The proposed trajectory model could provide safety lane-change path planning,and the designed controller could ensure good tracking and robust stability for the closed-loop nonlinear system.Originality/value–This is a fundamental research of intelligent local path planning and automatic control for articulated vehicles.There are two main contributions:thefirst is a more quantifiable trajectory model for self-driving articulated vehicles,which provides the opportunity to adapt vehicle and scene changes.The second involves designing a feedback linearization controller,combined with a multi-objective decision-making mode,to improve the comprehensive performance of intelligent vehicles.This study provides a valuable reference to develop advanced driving assistant system and intelligent control systems for self-driving articulated vehicles.

有轨电车集中控制与分布式控制转换机制研究

有轨电车作为城市公共交通的重要组成部分,其信号系统的效率和可靠性直接影响城市交通的整体流畅性和安全性。传统的信号系统多采用集中控制方式,但随着城市扩展和网络复杂性的增加,单一的集中控制模式已经难以满足所有的运营需求。因此,引入分布式控制,提高系统对局部故障的耐受性和自主调度能力变得尤为重要。然而,如何在集中控制和分布式控制之间根据实际情况灵活切换,是提升有轨电车信号系统性能的关键。

基于安全与高效的空调水循环泵选型方法与控制策略浅析

基于安全运行、服务保障和低碳节能的诉求,对空调冷水系统中冷水循环泵的不同设计理念和控制策略进行了比较分析,并对制冷站内并联运行的冷水泵设计选型和控制策略提出了商榷和探讨。分别从暖通空调和自动控制的不同专业角度,给出了多台相同性能水泵并联运行的安全保障技术措施。在对比分析冷源侧供回水总管压差和用冷侧最不利末端压差2种控制方案之后,介绍了1种多末端分布式压差控制解决方法,可供设计师参考。

XH凹陷中南部背斜带油气分布特征与成藏主控因素

为了厘清XH凹陷中南部背斜带的油气成藏主控因素,解剖了中南部T气田、H气田、R气田等3个典型油气田。研究表明:中南部背斜带油气成因、来源和成藏期次一致,但油气分布却存在显著差异性,主要表现在富集程度、纵向分布层位和平面赋存位置3个方面。分析认为,造成油气分布差异性的主控因素为断裂系统、烃源岩分布、源-储构造叠合关系和断-砂耦合关系。断裂系统的差异性决定纵向上油气分布层位以及构造内部的差异化富集程度;平湖组煤系烃源岩成熟度和厚度分布的差异性决定区域油气富集程度;花港组源外成藏背景下,成藏期平湖组烃源层顶面构造与花港组储集层构造叠合关系决定局部构造汇烃强度;中南部花港组强水道化背景下,断层与砂体耦合关系决定单层油气成藏规模。

无人机集群编队自主协同控制方法综述

自主协同控制是实现无人机集群高效协同编队的一种主流控制方法,属于当前无人机控制领域的研究热点和难点。论文首先从两类无人机集群编队自主协同控制主流类型切入。然后,重点对集中式控制类型中的领航者-跟随者法、虚拟结构法,和分布式控制类型中的人工势场法、行为法、一致性理论法、深度强化学习法等典型方法的基本思想、特点和最新研究进展进行了对比分析。最后,对无人机集群编队自主协同控制方法的发展趋势进行展望,以期为后续研究提供参考。

KJZ-2400/3300组合开关的常见故障分析

通过对KJZ-2400/3300组合开关控制线路的电源分配,以及对控制系统常出现的故障进行分析,明确了各类故障的判断依据和排除故障的方法,总结了组合开关各类故障处理经验,保障了设备的安全可靠运行。

基于改进黏菌算法优化BiLSTM的短期供热负荷控制预测

针对短期供热负荷控制预测的问题,提出了一种基于改进黏菌算法优化BiLSTM的预测模型。利用猫映射、T分布变异和随机反向学习等改进策略对黏菌算法进行改进,改进后的黏菌算法优化BiLSTM网络参数,构建ISMA-BiLSTM模型,对换热站热负荷进行预测。实验结果表明,ISMA-BiLSTM模型与SMA-BiLSTM、BiLSTM和LSTM模型相比,预测结果更加合理且预测精度有所提高,在短期供热负荷预测中能满足实际工程控制需要。

可视化中控系统在电力应急指挥中心的应用

为解决电力应急指挥中心运行指挥效率低下的问题,满足电力应急指挥中心运行时高效管理、控制各类智能化系统的需求,详细介绍了电力应急指挥中心对可视化中控系统的需求,分析了在设计可视化中控系统时要注意的问题,提出了设计可视化中控系统的观点。该系统可应用于电力应急指挥中心,具有集中控制处理大屏幕显示系统、视音频矩阵系统、音响系统、视频会议系统、灯光系统和电动窗帘等多个分散子系统的功能,满足电力应急指挥中心对各种设备综合控制的需求,且能够给用户提供友好而便捷的人机界面,达到减少操作工作量、创造良好环境、提高工作效率的目的。

工商业分布式光伏集中管控系统的设计与实现

在碳中和、限电减排、绿证交易放开等多重因素影响下,工商业分布式光伏电站的建设将以更快的速度增长,其中集中管控的问题越来越突出。针对工商业分布式光伏场站的现状及集中管控特点,提出了工商业分布式光伏集中管控系统的设计理念,研究了系统的构成、架构和功能,以期为新能源企业集中管控提供参考。

多Agent系统任务分配方法综述

任务分配问题是多Agent系统(multi Agent system,MAS)中的重要研究内容之一,即解决如何将合适的任务分配给合适的Agent以实现整体执行效果最优。在分析MAS四种典型控制架构的基础上,比较了集中式与分布式控制架构下任务分配问题的特点,并对目前MAS中的多种集中式和分布式分配方法分别进行综述。最后,从理论和应用研究两方面总结和分析了MAS任务分配问题的未来发展方向。

直流配电网的集中?分布式控制策略

直流配电网的协调运行策略是直流配电网研究的关键技术。提出了适用于直流配电网的集中-分布式控制架构,包括集中控制层和分布式控制层。集中控制层研究联网和离网运行协调控制策略。联网运行策略考虑了交流配网的实际消纳能力和储能的运行状态,被划分为换流站调节模式和换流站储能联调模式2种模式,能够最大化利用交流配网消纳能力同时尽可能使储能处在最佳状态,以此防备恶劣的情形,提高系统的稳定性。并根据不同模式下不同场景提出不同的协调策略。离网运行策略采用电压分层控制策略。分布式控制层研究每个本地端口的功能和本地策略。通过对研究的直流配电网仿真分析,验证了所提出的控制架构和控制策略的准确性和有效性,提高了直流配电网的电能质量。