Resilient Fixed-Order Distributed Dynamic Output Feedback Load Frequency Control Design for Interconnected Multi-Area Power Systems

The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.

Reliability and sensitivity analysis of loop-designed security and stability control system in interconnected power systems

Security and stability control system(SSCS)in power systems involves collecting information and sending the decision from/to control stations at different layers;the tree structure of the SSCS requires more levels.Failure of a station or channel can cause all the execution stations(EXs)to be out of control.The randomness of the controllable capacity of the EXs increases the difficulty of the reliability evaluation of the SSCS.In this study,the loop designed SSCS and reliability analysis are examined for the interconnected systems.The uncertainty analysis of the controllable capacity based on the evidence theory for the SSCS is proposed.The bidirectional and loop channels are introduced to reduce the layers and stations of the existing SSCS with tree configuration.The reliability evaluation and sensitivity analysis are proposed to quantify the controllability and vulnerable components for the SSCS in different configurations.By aiming at the randomness of the controllable capacity of the EXs,the uncertainty analysis of the controllable capacity of the SSCS based on the evidence theory is proposed to quantify the probability of the SSCS for balancing the active power deficiency of the grid.

Technical and Economical Merits of Power Systems Interconnection

This work aims at exploring the effects of the interconnection between isolated electric power systems upon some important aspects such as enhancing reliability levels along with reducing installation and operation costs. To discern the advantages associated with this study, the developed methodology has been applied to three existing power systems in the northern region of the Kingdom of Saudi Arabia presently within the concession domain of the Saudi Electric Company (SEC). These systems have been established to meet the present loads and to withstand future electrical demands for a period of time before additional generation and transmission reinforcements are needed. In this work, reliability measures have been utilized to determine the period that these systems can fulfill the present and future loads without affecting the reliability levels and the threshold that an additional capacity should be added to maintain those required reliability levels. In application to the reliability criteria, technical, operational and economic advantages can be realized, i.e., higher reliability levels and lower installation and operation costs after the proposed interconnection between these selected isolated power systems take place.

Research on Security Assessment Index System for Operating Reserve in Large Interconnected Power Grid

Optimization and placement of spinning reserve is an important issue in power system planning and operation. Systematic way for security assessment of operating reserve needs to study. A security assessment index system for operating reserve in large interconnected power grids is presented in this paper. Firstly, classification and determination methods of operating reserve at home and abroad are investigated, and operating reserve is divided into transient state operating reserve and quasi-steady state operating reserve from the view of security assessment. Secondly, assessment indexes and optimization methods for transient state operating reserve are studied. Thirdly, optimization model, deterministic and probabilistic optimization methods for quasi-steady state operating reserve are explored. Finally, some principles for determination of operating reserve are suggested, and a security assessment index system is put forward. The proposed index system, considering both transient and quasi-steady state, both deterministic and probabilistic methods, provides a systematic way to assessment and arrangement of operating reserve.

Obstacles Facing Developing Countries in Power System Planning

The problem of power system planning, due to its complexity and dimensionality, is one of the most challenging problems facing the electric power industry in developing as well as developed countries. In planning phase, two of the most important decision-making parameters are the reliability and costs. The latter includes both system investment costs and outages costs. In this paper, these parameters are described and the interrelation between them is evaluated. Some previous approaches and developed techniques will he applied to a particular planning problem in a developing country and some aspects having a significant impact on the decision making process in the planning phase will be considered.

交⁃直⁃交异步系统准同步控制下直流动态功频响应特性分析

经直流输电互联的异步系统通过对直流输电实施附加控制,可实现异步系统的准同步运行,达到实时共享异步系统调频资源的目的。但在准同步控制的工程实践中,不合理的控制结构或参数配置将导致系统出现非预期的功率波动。首先,根据直流准同步附加控制,构建准同步系统的动态功频响应分析模型;然后,基于该模型分析了直流控制参数对功率振荡的影响;进而,分析准同步控制导致的功率波动与传统功角振荡的异同;最后,以准同步实验过程中出现的功率波动为例进行分析验证,提出抑制直流功率波动的建议,并对准同步控制进行了讨论。

分布式储能在成都科幻馆的应用

通过电化学储能在2023年第81届世界科幻大会主场馆——成都科幻馆项目的示范应用,重点从应用场景、并网接入电压、接入系统方案、运行策略等方面分析用户侧分布式储能在民用建筑的应用要点。

海上多平台互联电力系统开环点连接开关同步检测和合闸技术

综合考虑海上多平台电力系统闭环设计开环运行方式的特点,采用基于频率修正的离散傅里叶算法(DFT)计算开环点LCB开关两侧不同频率母线电气量,并根据测量结果提出了事故情况下基于电源快速切换的合闸策略以及正常运行时多机组准同期的合闸策略。

IPS电力系统的教学平台建设可行性研究

目前,绝大多数电力系统教学设备已不适应电力行业最新科技发展趋势,为了满足电力系统教学领域要求,江西工业工程职业技术学院拟建设一套基于IPS互联电力系统的教学实验应用平台。该平台由无穷大系统、电力系统自动化实验台、线路保护实验台、变电站自动化实验台、工厂供电系统实验台、变压器保护实验台、负载、计算机组成的硬件部分,以及一套互联电力系统教学平台上位机监控管理软件和嵌入式软件组成的软件部分构成。此平台预计可为高校、职业学院以及企业培训机构的电力系统教学带来全新理念。

Dynamic stability enhancement of interconnected multi-source power systems using hierarchical ANFIS controller-TCSC based on multi-objective PSO

Suppression of the dynamic oscillations of tie-line power exchanges and frequency in the affected interconnected power systems due to loading-condition changes has been assigned as a prominent duty of automatic generation control(AGC). To alleviate the system oscillation resulting from such load changes, implementation of flexible AC transmission systems(FACTSs) can be considered as one of the practical and effective solutions. In this paper, a thyristor-controlled series compensator(TCSC), which is one series type of the FACTS family, is used to augment the overall dynamic performance of a multi-area multi-source interconnected power system. To this end, we have used a hierarchical adaptive neuro-fuzzy inference system controller-TCSC(HANFISC-TCSC) to abate the two important issues in multi-area interconnected power systems, i.e., low-frequency oscillations and tie-line power exchange deviations. For this purpose, a multi-objective optimization technique is inevitable. Multi-objective particle swarm optimization(MOPSO) has been chosen for this optimization problem, owing to its high performance in untangling non-linear objectives. The efficiency of the suggested HANFISC-TCSC has been precisely evaluated and compared with that of the conventional MOPSO-TCSC in two different multi-area interconnected power systems, i.e., two-area hydro-thermal-diesel and three-area hydro-thermal power systems. The simulation results obtained from both power systems have transparently certified the high performance of HANFISC-TCSC compared to the conventional MOPSO-TCSC.

基于MVO算法与改进目标函数的电力系统负荷频率控制

针对风电并网时的随机波动功率、负荷频率控制(load frequency control, LFC)系统参数变化所引起的电力系统频率稳定问题,提出了一种基于智能优化算法与改进目标函数的互联电网LFC系统最优PID控制器设计方法。首先,分析了基于PID控制的含风电互联电力系统LFC闭环模型。其次,在时间乘误差绝对值积分(integral of time multiplied absolute error, ITAE)性能指标的目标函数中考虑了区域控制器的输出信号偏差,对优化目标函数进行改进。采用性能优良的多元宇宙优化(multi-verse optimizer, MVO)算法先计算后验证的思路,寻优获得最优PID控制器参数。最后,以两区域4机组互联电力LFC系统为例,仿真验证了基于MVO算法结合改进目标函数所获得的PID控制器,比基于MVO算法所获得的PID控制器,对阶跃负荷扰动、随机负荷扰动、风电功率偏差扰动以及系统的参数变化,具有相对较好的鲁棒性能。并且,对控制器参数也具有相对较好的非脆弱性指标。

基于直流线路互联的区-隧供电系统弹性恢复策略

在“双碳”目标下,以服务区光伏车棚、光伏隧道为代表的能源交通融合供电场景逐步普及,这使得形态开放且布局分散的区-隧供电系统在面临极端灾害或人为攻击时更为脆弱。为此,该文提出一种基于直流线路互联的区-隧供电系统弹性恢复策略。根据灾害前对直流线路的改造与韧性加固计划,首先,提出了基于直流线路被优先遍历的可行拓扑搜索策略,用于保障所提系统在极端灾害后的有效互联;其次,基于对故障负荷重要级权重的多层级分类策略,该文先后以重要负荷恢复量最大化和系统额外损耗最小化为目标构建了故障恢复目标函数,共同保证极端灾害发生后系统基于稀缺分布式能源的最大弹性恢复;再次,基于传统二阶锥松弛方法可能挣脱原始约束的缺陷,提出通过约束额外损耗中流经电流分量实现对混合整数二阶锥规划问题的收敛,确保所提模型在不同初始条件下的稳定适用;最后,通过涵盖区-隧供电系统的改进IEEE 123节点配电网进行仿真,验证了所提策略的有效性。

区域互联下不对称交流电网运行控制系统设计

电力系统内部的交流电在产生不对称故障之后,会直接导致换流站母线电压不平衡,系统内部出现的负序分量和零序分量会影响系统交流和直流谐波分布,进而影响电网的正常运行。为了进一步实现不对称交流电网的控制,设计了一种控制系统。系统硬件设计了锁相环控制器、电流环控制器、DSP控制器,锁相环控制器由相位鉴别、环路滤波和压控振荡三部分组成一个闭环。针对区域互联状况进行分析,确定谐波电压和谐波电流的传递规律,建立谐波分析程序和控制程序,通过矢量计算,对不对称交流电网电流进行运行控制。实验结果表明,所设计系统能够有效解决运行过程的输入量和输出量不均衡的问题,降低叠加放大状况,控制后电流和电压幅值波动为0,有效防止出现谐波不稳定现象。

基于PoE供电的楼宇智能互联照明系统设计

随着物联网技术的发展,智能照明系统已成为建筑能源管理的重要组成部分。文章以Po E供电的楼宇智能互联照明系统为研究对象,探讨其设计方案。首先介绍了Po E技术原理及其在照明系统中的应用,然后详细阐述了系统架构、硬件设计和软件设计。在硬件设计中,考虑了照明系统的功率需求,采用了高效的LED灯具和节能型电源。在软件设计中,结合人体感知、环境变化和光源特性等因素,设计了智能照明控制算法。最后,对系统进行了仿真和实验验证,结果表明该系统具有良好的能效和稳定性,具备实际应用价值。

含光伏和风电的互联电力系统概率最优潮流

为了实现更大范围的资源优化配置,提高光伏和风电的消纳能力,实现“双碳”目标以及在更大的市场内进行竞争,互联电网各区域间联络断面功率必须调整至指定值以满足交易功率约束。为此,针对含光伏和风电的互联电网,提出了考虑交易功率约束的概率最优潮流模型及算法。首先以网损为目标函数,考虑交易功率约束以及光伏和风电的间歇性,建立了概率最优潮流模型,然后采用随机响应面法求解概率最优潮流。针对IEEE 30节点系统改造而成的互联电网进行仿真分析,验证了所提模型和方法的正确性和有效性。

采用潮流控制器的贯通型牵引供电系统负序治理模型及控制策略

针对树形双边贯通牵引供电系统负序导致的电力系统侧公共连接点处三相电压不平衡问题,提出在树形双边贯通牵引供电系统中加装由降压变压器、潮流控制器(PFC)和控制器组成的补偿装置进行功率转移的负序补偿方案;在建立采用PFC的贯通型牵引供电系统拓扑结构和数学模型的基础上,设计合理的约束参数和控制策略,通过控制补偿装置改变电力系统侧功率分布,从而实现负序补偿;采用MATLAB/Simulink仿真试验平台,分析补偿装置所需容量随负序补偿程度的变化规律,并计算最小化负序补偿容量,对补偿方案进行验证。结果表明:基于功率转移的负序补偿方案能够灵活调节公共连接点处负序功率和无功功率含量;可将公共连接点处三相电压不平衡度的最大值降低至4%,95%统计值降低至2%,满足了国家标准,从而验证了基于功率转移负序补偿方案的有效性。

新型铁路电源净化装置的典型应用

铁路电力系统是电力系统网络的重要组成部分,正在向着智能电网的方向发展。文章以铁路电力系统的构成为基础,阐述了铁路牵引电力系统和铁路电力供配电系统高效互联装备的应用需求与工程应用情况,介绍了一种铁路净化电源装置,分析了其目前面临的挑战和工程测试情况。结果表明,该装置在铁路电力系统中有较高的实用性。

含储能的区域互联电力系统负荷频率预设性能控制

针对大规模新能源影响电力系统频率稳定的问题,对含储能的区域互联电力系统负荷频率控制进行了研究。首先,建立系统状态空间模型;然后,为了使区域控制偏差快速收敛至目标值,引入预设性能函数,采用预设性能控制的方法对跟踪误差进行转换,设计了具有预设性能的控制器;最后,将控制器的输出作为储能系统的参考信号,储能系统再输出相应的功率至区域互联电力系统中。基于两区域互联电力系统进行仿真验证,仿真结果表明:与模型预测控制策略相比,所提控制策略能够更为快速地将区域互联电力系统的频率偏差和区域控制偏差限制在稳定范围内,维持区域互联电力系统的稳定,改善系统调频效果。

电热综合能源系统稳态与区间潮流计算快速解耦新方法

综合能源系统稳态潮流计算是后续规划、运行等研究的基础。目前常采用的牛顿-拉夫逊法存在数值稳定性问题,且随着综合能源系统不确定因素增加,研究系统的区间潮流以实现综合能源系统的安全分析和评估变得越来越重要。首先,基于泰勒函数一阶展开和二阶展开,推导出热负荷流量和节点温度的解析表达式,该表达式实现了流量与温度的独立求解,无须解方程组即可得到系统稳态潮流。然后,分析流量和温度表达式的函数单调性,结合各热负荷值,确定了热负荷流量和热负荷节点温度的区间潮流解,所提方法在保证计算精度的同时,计算速度快且不存在数值稳定性问题。最后,通过算例分析验证了所提方法的有效性。