摘要:The electric distribution system (EDS) is prone to faults leading to power interruptions. The present energy market demands that electricity utilities invest more in different measures to improve the performance of the EDS. The approach proposed here details a composite dual-phased methodology to improve the reliability and efficiency of the power delivered by the EDS. In the first phase, the optimal allocation of auto-reclosers (AR) is undertaken by employing a newly formulated algorithm. The determination of the total number and location for AR placement is based on the economic analysis of two factors, i.e., AR investment-maintenance cost and total benefit earned in terms of reliability improvement due to AR placement. The analysis also takes into account the impact of power outages on different load types, the load growth rate, and the inflation rate. Further, to enhance the efficiency of the AR-incorporated EDS, the technique of Radial Distribution System Remodelling is employed in the second phase. This method searches for a radial configuration that delivers power at minimum line losses. These phases comprising complex combinatorial operations are aided by a fresh hybrid of the Sine Cosine Algorithm, Krill Herd Algorithm, and a genetic operator of Differential Evolution. The results obtained from its application on the IEEE 69-bus distribution test system prove the credibility of the suggested formulation.

摘要:为解决小电流接地系统在相电压过零点附近特征频带选取结果不准确、保护装置采样不同步等问题，详细分析了零模网络下配电线路的相频特性，并据此提出一种基于特征频带暂态无功功率相关性检测的选线新方法。首先，对各出线暂态零模电流与母线差分零模电压进行交叉小波变换，将二者相关性较强且相位差稳定的区域作为故障选线的时频窗。然后，利用时频窗内暂态电压电流信号的幅值与相位信息计算得到暂态无功功率。最后，根据特征频带内故障线路暂态无功功率与非故障线路暂态无功功率流向相反的特点，利用互相关函数算法对各出线暂态无功功率的相关性进行检测，确定故障线路。理论分析和仿真结果表明，所提方法不受故障初始角、同步误差、噪声干扰等因素的影响，对高阻以及弧光接地具有较强的适应性，且适用于分布式电源接入的配电网单相接地故障选线。

摘要:电力电子化的直流微电网自身缺乏惯性，当功率发生波动时，直流母线电压会产生较大突变，不利于其稳定运行。为了解决这一问题，虚拟直流电机控制被应用于直流变换器中来模拟直流电机的外特性，进而为直流微电网提供惯性支撑。但传统参数固定的虚拟直流电机控制在提供惯性的同时会牺牲系统的动态响应速度。针对这一问题，提出了参数自适应虚拟直流电机控制，并将它应用于储能端推挽式DC/DC变换器中。建立了系统的小信号模型，分析了转动惯量参数变化对系统的影响，并给出了参数的自适应调节原则。最后，搭建了仿真模型对不同控制方法进行了对比分析。仿真结果表明所提控制策略在为系统提供较大惯性支撑的同时，系统仍具有较快的动态响应速度。

摘要:In feeder automation transformation there are difficulties in equipment and location selection. To help with this, an optimal layout model of feeder automation equipment oriented to the type of fault detection and local action is proposed. It analyzes the coordination relationship of the three most common types of automation equipment, i.e., fault indicator, over-current trip switch and non-voltage trip switch in the fault handling process, and the explicit expressions of power outage time caused by a fault on different layouts of the above three types of equipment are given. Given constraints of power supply reliability and the goal of minimizing the sum of equipment-related capital investment and power interruption cost, a mixed-integer quadratic programming model for optimal layout is established, in which the functional failure probability of equipment is linearized using the 3δ principle in statistics. Finally, the basic characteristics of the proposed model are illustrated by different scenarios on the IEEE RBTS-BUS6 system. It can not only take into account fault location and fault isolation to enhance user power consumption perception, but also can guide precise investment to improve the operational quality and efficiency of a power company.

摘要:电网发生不对称故障会影响新能源并网系统可靠运行，严重情况下还会存在切机风险。针对上述问题，提出一种不对称故障下考虑电压跌落程度的电压支撑策略。首先根据逆变器在不对称故障下的输出特性，分析了对公共连接点(point of common coupling, PCC)电压的支撑原理。然后推导了任意不对称故障下PCC电压幅值的通式，进而分析了改变无功电流注入方式的临界点。最后在上述基础上，以逆变器输出电流峰值和已利用容量为约束条件，分别对3种典型的不对称故障进行了分析。确定了每种故障在不同电压跌落阶段的最优无功电流，并推导了各电压跌落阶段的电流参考值计算公式。仿真验证了所提控制策略的有效性与优越性。

摘要:This paper offers a systematic literature review of real-time detection and classification of Power Quality Disturbances (PQDs). A particular focus is given to voltage sags and notches, as voltage sags cause huge economic losses while research on voltage notches is still very incipient. A systematic method based on scientometrics, text similarity and the analytic hierarchy process is proposed to structure the review and select the most relevant literature. A bibliometric analysis is then performed on the bibliographic data of the literature to identify relevant statistics such as the evolution of publications over time, top publishing countries, and the distribution by relevant topics. A set of articles is subsequently selected to be critically analyzed. The critical review is structured in steps for real-time detection and classification of PQDs, namely, input data preparation, preprocessing, transformation, feature extraction, feature selection, detection, classification, and characterization. Aspects associated with the type of disturbance(s) addressed in the literature are also explored throughout the review, including the perspectives of those studies aimed at multiple PQDs, or specifically focused on voltage sags or voltage notches. The real-time performance of the reviewed tools is also examined. Finally, unsolved issues are discussed, and prospects are highlighted.

摘要:为简化含分布电源的配电网故障定位算法过程，并提高故障定位算法的容错性，以矩阵算法为基础提出一种改进的区段定位算法。首先，建立描述节点区段关系的结构描述矩阵，并通过判断是否检测到过电流及过流方向建立故障信息矩阵。然后，利用结构描述矩阵和故障信息矩阵相乘得到故障判断矩阵，并根据区段对应矩阵中行元素构成的不同将区段划分类型，建立各类型区段下反映所有故障情况的故障判据。最后，对照故障判断矩阵行元素与故障判据，判断出发生故障的区段。针对配网中FTU上传信息易发生畸变的情况，提出了基于相量校正的信息畸变校正方法，通过故障电流与正常运行电流相位差异进行定位结果的修正，降低故障信息畸变对定位结果的影响。对DG的投切状况以及配电网两相和三相短路的单重多重故障进行仿真，结果验证了所提故障定位算法的原理简单、准确度好并具有一定的容错能力。

摘要:快速、可靠的电力系统动态安全评估能够显著提高电力系统运行方式优化调整的效率。针对电力系统暂态稳定预想事故扫描需要完成大量仿真、过于耗时的问题，提出了基于图卷积网络的快速动态安全分析方法。该方法基于电力系统的潮流特征和拓扑特征构建电力系统潮流特征图。利用图卷积方法对电力系统运行状态进行特征挖掘与特征学习，将动态安全评估问题建模为图上节点分类问题。所得模型在读取电网拓扑与潮流运行状态后，仅须完成一次前向计算即可同时给出预想事故集中多个预想事故的稳定性预测结果，无须依赖仿真波形或量测数据，实现快速暂态稳定预想事故扫描。IEEE39节点系统算例测试表明，算法设计正确、高效、准确率高，能够显著提高暂态稳定预想事故扫描的效率，实现快速动态安全评估。

摘要:针对含链式静止无功发生器(static var generator, SVG)的风场区域系统高频谐振问题，首先采用谐波线性化的方法建立包含锁相环、功率外环以及电流内环在内的SVG谐波阻抗模型。利用阻抗分析法对风场区域空载线路投入对SVG稳定性的影响进行分析，揭示风场区域系统高频谐振的发生机理。然后，为抑制系统高频谐振，提出一种基于电压前馈附加带阻滤波器的SVG高频谐振抑制策略。对SVG侧中高频段等效阻抗进行重塑，以保证在该频段系统呈正阻尼状态。并讨论带阻滤波器中心频率和阻尼系数对系统相位裕度的影响。最后利用搭建的含链式SVG风场区域系统仿真模型，验证了理论分析的正确性和所提抑制策略的有效性。

摘要:为了提高谐振接地系统单相接地选线的抗过渡电阻能力，提出一种基于相关检测的单相接地选线方法。采用低频方波对消弧线圈补偿电流进行调制，分析故障线路与健全线路调制后的信号特征。将各条线路零序电流分别除以零序电压包络幅值加以调整后进行解调和相关检测。构造了基于互相关函数的单相接地选线判据，讨论了低频调制方波频率的选择对选线效果的影响。结合实例对所提出的方法进行了仿真和实验研究，结果表明所提方法在单相接地选线方面具有非常高的抗过渡电阻能力。

摘要:To address the challenges in fault location in distribution networks, the distribution of magnetic field under overhead line and its relationship with three-phase currents are explored in this paper. At the same time, considering the influence of sensor installation position, line sag and galloping on magnetic field, a grounding fault location method of an overhead line based on dual-axis magnetic field trajectory is proposed. The analytical expressions of the magnetic field on the x-axis and y-axis under the overhead line are obtained by least squares fitting. The Lissajous figure synthesized by dual-axis is then compared with the general equation of an ellipse, and the characteristic quantity expression characterizing the magnetic field trajectory structure is obtained. Finally, a fault location criterion is constructed using the difference of the characteristic quantities of the ellipses synthesized by x-axis and y-axis magnetic fields upstream and downstream of the fault point, i.e., the difference of the length of the major axis and the minor axis, and the sign for the ratio of the cosine value of the inclination angle. Compared with other location methods based on electrical quantity, the principle of this method is simpler and it can locate faults more quickly and accurately. A large number of simulation results show that the proposed method is suitable for different types of fault conditions.

摘要:在我国中长期合同交易与现货市场衔接的政策背景下，中长期合同电量必须分解至短时间尺度。针对发电商中长期合同电量的自主分解问题，研究了发电商在现货市场价格严重不确定环境下基于分布鲁棒优化的中长期合同电量分解方法。首先，针对现货价格的严重不确定性，以Wasserstein距离作为分布函数距离测度，构建了现货价格分布不确定性的模糊集。其次，建立了发电商合同分解的分布鲁棒优化模型。以发电商利润最大化为目标，考虑发电商运行约束和合同分解约束，并采用对偶理论等将模型转化为可高效求解的二次规划问题。最后，通过算例仿真并与传统的随机优化和鲁棒优化模型进行对比。结果表明所提模型在处理现货价格不确定性时能有效兼顾发电商合同分解决策的经济性和鲁棒性。

摘要:为使模块化多电平换流器(modular multilevel converter, MMC)具备直流故障自清除能力和电容电压均衡能力，提出了一种新型并联双端口子模块：钳位双全桥子模块(clamp double full bridge submodule, CD-FBSM)。该子模块器件成本和运行损耗较低，正常工作时相邻子模块之间具有多种协同运行模式，通过特有的并联模式可提高电容电压均衡度。故障闭锁时，模块内部电容并联、模块之间电容串联且反向接入电路，能够可靠阻断故障电流并均衡电容电压，有利于系统快速重启。此外，提出了三阶段故障电流阻断机理分析方法，对CD-FBSM的故障电流阻断过程进行了研究。通过Matlab/Simulink的仿真结果表明，所提子模块电容电压均衡度较高，可快速阻断故障电流，且故障电流阻断过程与理论分析一致。

摘要:Data-driven preventive scanning for transient stability assessment (DTSA) is a faster and more efficient solution than time-domain simulation (TDS). However, most current methods cannot balance generalization to different topologies and interpretability, with simple output. A model that conforms to the physical mechanism and richer label for transient stability can increase confidence in DTSA. Thus a static-information, k-neighbor, and self-attention aggregated schema (SKETCH) is proposed in this paper. Taking only static measurements as input, SKETCH gives several explanations that are consistent with the physical mechanisms of TSA and provides results for all generator stability while predicting system stability. A module based on the self-attention mechanism is designed to solve the locality problem of a graph neural network (GNN), achieving subgraph equivalence outside the k-order neighborhood. Test results on the IEEE 39-bus system and IEEE 300-bus system indicate the superiority of SKETCH and also demonstrate the rich sample interpretation results.

摘要:为了更准确地分析我国特高压输电线路雷电绕击屏蔽性能，基于我国长空气间隙放电试验数据和雷电回击观测数据，建立考虑地形条件的适应于大尺寸输电线路雷电屏蔽性能评估的改进电气几何模型(electric geometry model, EGM)并进行验证，将击距公式修正为rs = 0.13(I 2+ 40I)0.814。改进EGM模型对超、特高压输电线路三相导线的雷电绕击率计算结果与日本实际线路雷击观测数据及我国平原、山区特高压输电线路雷击模拟试验数据具有一致性，验证了改进EGM模型的适用性。采用改进EGM模型评估了杆塔型式、山坡陡度对我国特高压线路绕击跳闸率的影响。计算结果表明，采用SZ322型杆塔的绕击跳闸率高于采用SZT1型杆塔，且特高压线路绕击跳闸率随山坡陡度的增大而增大。EGM模型的修正以及计算方法的优化，对我国特高压输电线路雷电屏蔽性能的设计具有一定的指导意义。

摘要:In the presence of an MMC-HVDC system, current differential protection (CDP) has the risk of failure in operation under an internal fault. In addition, CDP may also incur security issues in the presence of current transformer (CT) saturation and outliers. In this paper, a current trajectory image-based protection algorithm is proposed for AC lines connected to MMC-HVDC stations using a convolution neural network improved by a channel attention mechanism (CA-CNN). Taking the dual differential currents as two-dimensional coordinates of the moving point, the moving-point trajectories formed by differential currents have significant differences under internal and external faults. Therefore, internal faults can be identified using image recognition based on CA-CNN. This is improved by a channel attention mechanism, data augmentation, and adaptive learning rate. In comparison with other machine learning algorithms, the feature extraction ability and accuracy of CA-CNN are greatly improved. Various fault conditions like different network structures, operation modes, fault resistances, outliers, and current transformer saturation, are fully considered to verify the superiority of the proposed protection algorithm. The results confirm that the proposed current trajectory image-based protection algorithm has strong learning and generalizability, and can identify internal faults reliably.

摘要:双碳愿景下，维持高比例新能源电力系统的稳定性和灵活性，配置储能是关键。建立了考虑阶梯式碳交易和分时电价的储能鲁棒模型。在模型中考虑了源荷双侧的不确定性影响，利用时间平滑约束和空间集群约束来缩小源荷不确定性集边界，降低模型的保守性。通过拉格朗日推理把不确定性约束转换为确定性约束，并用改进的麻雀算法对模型进行求解。算例表明，时空耦合效应下系统经济性将得到显著提升，决策者可通过选择不确定性的置信概率来平衡系统经济性与鲁棒性。针对不同灵活性改造阶段提出了不同的储能规划方案，指出区域内火电存量低于43%时，系统开始具有碳收益。

摘要:Voltage instability is a serious phenomenon that can occur in a power system because of critical or stressed conditions. To prevent voltage collapse caused by such instability, accurate voltage collapse prediction is necessary for power system planning and operation. This paper proposes a novel collapse prediction index (NCPI) to assess the voltage stability conditions of the power system and the critical conditions of lines. The effectiveness and applicability of the proposed index are investigated on the IEEE 30-bus and IEEE 118-bus systems and compared with the well-known existing indices (Lmn, FVSI, LQP, NLSI, and VSLI) under several power system operations to validate its practicability and versatility. The study also presents the sensitivity assumptions of existing indices and analyzes their impact on voltage collapse prediction. The application results under intensive case studies prove that the proposed index NCPI adapts to several operating power conditions. The results show the superiority of the proposed index in accurately estimating the maximum load-ability and predicting the critical lines, weak buses, and weak areas in medium and large networks during various power load operations and contingencies. A line interruption or generation unit outage in a power system can also lead to voltage collapse, and this is a contingency in the power system. Line and generation unit outage contingencies are examined to identify the lines and generators that significantly impact system stability in the event of an outage. The contingencies are also ranked to identify the most severe outages that significantly cause voltage collapse because of the outage of line or generator.

摘要:模块化多电平变换器(modular multilevel converter, MMC)内部环流增加系统功率损耗，加剧桥臂电流畸变。针对传统PI环流控制器存在鲁棒性较差、控制精度有限等问题，将分数阶PI 控制器应用于MMC环流抑制。首先，对MMC工作特性进行分析，阐述环流产生机理。其次，研究分数阶PI 控制结构，并设计MMC分数阶PI 环流抑制策略。然后，采用经典频域法优化分数阶PI 控制器参数，并对分别采用传统PI和分数阶PI 控制器的系统环流控制性能进行对比分析。最后，在相同条件下，通过对采用上述两种环流抑制策略的MMC系统，分别在电源扰动、直流侧电压阶跃和三相不平衡工况下进行仿真研究。结果表明，分数阶PI 环流抑制器的抗电源扰动性和环流抑制能力均优于传统PI环流抑制器，更适用于MMC此类的非线性系统的控制。

摘要:为了实现锂电池健康状态检测和电池故障诊断，在电池全生命周期退化数据基础上，分别使用容量增量分析和差分电压分析法进行特征提取，使用皮尔逊相关系数对健康因子进行相关性分析，并将其输入到人工神经网络用于电池健康状态(state of health, SOH)预测。针对电池容量非线性的退化特性以及局部重生现象，使用双指数函数对其进行建模。同时结合粒子滤波算法对模型参数进行估计，实现电池剩余使用寿命(remaining useful life, RUL)的概率密度预测。实验结果表明所提出的方法能够实现SOH的精准预测和RUL的不确定性估计。

摘要:光伏出力短期预测对于电网或微电网的能量管理和优化调度具有重要意义。构建了一种基于改进灰狼学习算法(improved grey wolf optimization, IGWO)的脉冲神经网络(spiking neural network, SNN)，并将其应用到光伏出力短期预测中。首先，利用灰色关联分析法选取相似日。然后，提出一种IGWO算法用于SNN模型训练，通过引入基于三角函数规律变化的非线性下降收敛因子和动态权重更新策略，提升SNN的编码和预测的性能。最后，利用实证系统对所提方法进行了评估，并与其他3种模型进行了对比研究。结果表明，所提方法预测性能提升明显。

摘要:针对电力系统中带外干扰、频率偏移及其他动态情况下的谐波相量估计问题，提出了一种基于余弦平顶窗的谐波相量估计器。首先基于余弦窗频域表达式，利用理想幅值响应和最小二乘法获得平顶窗的窗系数。在此基础上，为使得滤波器频率响应在标称谐波频率下具有零增益，将所得窗函数与频域采样定理相结合，通过最小二乘法设计一组有限脉冲响应滤波器，用于估计谐波相量。然后，分析了余弦平顶窗和谐波相量测量滤波器的频率响应。最后，采用稳态和动态条件下的不同信号模型对提出的谐波相量估计器进行了性能验证。仿真结果表明，相对于基于Sinc插值函数和频域采样定理的两种谐波相量估计器，所提方法有较强的带外干扰抑制能力，在多种条件下能实现较高精度的谐波相量测量。

摘要:In this paper, a Backstepping Global Integral Terminal Sliding Mode Controller (BGITSMC) with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been presented. The proposed approach controls the switching signals of the inverter, interlinking the DC-bus with the AC-bus in an AC/DC microgrid for a seamless interface and regulation of the output power of renewable energy sources (Solar Photovoltaic unit, PMSG-based wind farm), and Battery Energy Storage System. The proposed control approach guarantees the dynamic stability of a hybrid AC/DC microgrid by regulating the associated states of the microgrid system to their intended values. The dynamic stability of the microgrid system with the proposed control law has been proved using the Control Lyapunov Function. A simulation analysis was performed on a test hybrid AC/DC microgrid system to demonstrate the performance of the proposed control strategy in terms of maintaining power balance while the system’s operating point changed. Furthermore, the superiority of the proposed approach has been demonstrated by comparing its performance with the existing Sliding Mode Control (SMC) approach for a hybrid AC/DC microgrid.

摘要:分析了消弧逆变器等效负载的性质，结果表明：等效负载是有源负载，等效源具有较大的幅值和较宽的变化范围；随过渡电阻和故障距离的变化，等效负载阻抗可呈现阻性、阻感性和阻容性。这一结果表明逆变器需要在负载性质改变和等效电源扰动的情况下，仍能稳定跟踪包含多频次的给定电流。对抗扰性和跟踪性要求的提高，增加了设计难度。鉴于此，提出了消弧逆变器输出滤波器和控制器的设计方法。输出滤波器采用滤波电容分流法进行设计，保证了逆变器能输出包含多频次的电流。采用电容串联电阻来抑制阻感负载情况下带来的谐振失稳问题，并给出了串联电阻的计算方法。控制器采用了定带宽设计法，带宽选定在幅频特性重合段。控制器参数设计准则为：保证阻容负载情况下传函幅频特性低频段具有较高增益。采用PSCAD/EMTDC仿真验证了结论的正确性和所提设计方法的可行性。

摘要:Hydrogen energy plays an important role in achieving carbon neutralization, and plasma induced hydrogen is an effective production method. One challenge is how to guarantee high efficiency operation with wide power output range of the RF inverter system used to generate the plasma. In this paper, a multi-module parallel topology of a high-frequency inverter is analyzed, in which the power combining network can maintain the soft switching characteristics of the inverter modules. A control method of "ON/OFF + phase shift" is adopted to broaden the output power range of the inverter. The equivalent impedances of different modules are analyzed in detail. A four-module 13.56 MHz high-frequency inverter prototype is built and tested. The results show that the inverter can operate at high efficiency and wide output power range with efficiency improved by at least 5% compared with the traditional parameter design method without considering the effect of paralleled modules.

摘要:当高压直流输电系统换流变阀侧发生单相接地故障，由于换流阀的单向导通性，阀侧故障电流中含有较大的直流分量，流入换流变可能导致换流变饱和并产生“故障性涌流”。与传统三大涌流不同，故障性涌流由阀侧单相接地故障诱发并受直流控制与保护系统的影响。计及直流控保系统的影响，分析了逆变侧换流变发生阀侧单相接地故障时，换流变故障性涌流的产生机理及其对换流变差动保护的影响。针对换流变保护区内阀侧单相接地故障场景下，故障性涌流可能导致差动保护误闭锁的问题，提出了一种基于选相投旁通对的故障性涌流主动抑制策略，可以从根本上避免差动保护误闭锁问题。基于PSCAD/EMTDC的仿真实验验证了所提方案的有效性。

摘要:The high proportion of nonlinear and unbalanced loads results in power quality issues in islanded microgrids. This paper presents a novel control strategy for harmonic and unbalanced power allocation among distributed generators (DGs) in microgrids. Different from the existing sharing strategies that allocate the harmonic and unbalanced power according to the rated capacities of DGs, the proposed control strategy intends to shape the lowest output impedances of DGs to optimize the power quality of the microgrid. To achieve this goal, the feasible range of virtual impedance is analyzed in detail by eigenvalue analysis, and the findings suggest a simultaneous adjustment of real and imaginary parts of virtual impedance. Because virtual impedance is an open-loop control that imposes DG to the risk of overload, a new closed-loop structure is designed that uses residual capacity and absorbed power as feedback. Accordingly, virtual impedance can be safely adjusted in the feasible range until the power limit is reached. In addition, a fuzzy integral controller is adopted to improve the dynamics and convergence of the power distribution, and its performance is found to be superior to linear integral controllers. Finally, simulations and control hardware-in-the-loop experiments are conducted to verify the effectiveness and usefulness of the proposed control strategy.

摘要:为有效抑制高压直流输电系统在不同故障程度下的换相失败，提出了一种基于自适应电压限值的改进低压限流控制器(voltage dependent current order limiter, VDCOL)设计方案。首先，详细分析了包含传统VDCOL的直流输电系统在换相失败及恢复期间的运行特性，并提出VDCOL曲线在不同时间段下应具备的动态性能。然后，引入直流电流这一反映故障特性的时变电气量优化传统VDCOL的直流电压上下限值，从而在不同时间段自适应改变电流指令启动电压阈值与电压-电流指令变化趋势，以满足输电系统换相失败及恢复期间的有功与无功需求。同时考虑到VDCOL电压上下限值的过度变化会恶化系统运行特性，对其范围的设置进行了解析和合理选取。最后,在PSCAD/EMTDC中对所提方法进行仿真测试。结果表明，所提出的改进控制策略能在一定程度上抑制直流输电系统的连续换相失败，同时有效地改善换相失败各阶段直流输电系统的运行特性。

摘要:采用合理的方法进行风电机组健康状态评价对于分配风电场功率，减少运维成本，延长风电机组使用寿命有着重要意义。随着装机容量的增长，风电机组健康状态评价引起了国内外学者的广泛关注。目前健康状态评价方法较为繁杂，且对于风电机组健康状态评价方法的总结归纳较少。因此，基于现有研究成果，对风电机组健康状态评价的现状进行梳理。首先，介绍了风电机组健康状态评价的方法，并对已有方法进行分类，分析了其优缺点。其次，介绍了风电机组健康状态评价的数据来源及描述其健康程度的指标。最后，从健康状态评价的数据分析、机组健康状态与控制的相互影响、整机的健康状态评价及预测等方面提出未来可研究的要点。

摘要:The challenge of controlling frequency becomes greater as the complexity of a power network increases. The stability of a power system is highly dependent upon the robustness of the controller. This paper presents automatic generation control (AGC) of a four-area interconnected power system along with integrated renewable energy sources of PV and wind energy. The designed model is a challenge given the increased penetration levels of PV and wind along with a thermal-hydropower system. The addition of a hydropower system as a fourth type results in the pole of the open loop system of the hydropower system being located at the right half side of the s-plan. This demands a robust control. A novel MPC-(1 + PIDN) is designed for high-order interconnected areas (HOIA) to stabilize the frequency in a robust way. The salp swarm algorithm is adopted to optimize the parameters of the PIDN controller. The performance of the proposed controller under HOIA is tested in a unbalanced load environment with uncertainty in the power system. The proposed controller can effectively handle the frequency disruption by stabilizing it in 0.86s for Area-1, 1.08s for Area-2, 0.81s for Area-3, and 0.84s for Area-4 with an average time of 0.89s for all the areas, whereas the average time for GWO: PI-PD, MPC/PI and GA-PI is 3.48s , 10.36s and 18.47s , respectively. The results demonstrate the effectiveness of the controller when compared to other controllers.

摘要:The large application of renewable energy generation (REG) has increased the risk of cascading failures in the power system. At the same time REG also provides the possibility of new approaches for the suppression of such failures. However, the capacity and position of the synchronous generator (SG) involved in regulation limit the power regulation speed (PRS) of REG to the overload line which is the main cause of cascading failures, while the PRS of SG is related to the position and shedding power. REG and SGs have difficulty in achieving effective cooperation under constraints of system power balance. Particularly, the dynamic variation of line flow during power regulation causes new problems for the accurate evaluation of line thermal safety under overload. Therefore, a new strategy for quantitatively coordinating shedding power and power regulation to block cascading failures in the dynamic security domain is proposed in this paper. The control capability and dynamic security domain of the overload line are modeled, and the coordination control method based on power regulation is then proposed to minimize shedding power. The algorithm for the optimal control scheme considers the constraints of load capacity, power source capacity and bus PRS. The correctness of the proposed method is verified using case studies.

摘要:The technological, economic, and environmental benefits of photovoltaic (PV) systems have led to their widespread adoption in recent years as a source of electricity generation. However, precisely identifying a PV system's maximum power point (MPP) under normal and shaded weather conditions is crucial to conserving the maximum generated power. One of the biggest concerns with a PV system is the existence of partial shading, which produces multiple peaks in the P–V characteristic curve. In these circumstances, classical maximum power point tracking (MPPT) approaches are prone to getting stuck on local peaks and failing to follow the global maximum power point (GMPP). To overcome such obstacles, a new Lyapunov-based Robust Model Reference Adaptive Controller (LRMRAC) is designed and implemented to reach GMPP rapidly and ripple-free. The proposed controller also achieves MPP accurately under slow, abrupt and rapid changes in radiation, temperature and load profile. Simulation and OPAL-RT real-time simulators in various scenarios are performed to verify the superiority of the proposed approach over the other state-of-the-art methods, i.e., ANFIS, INC, VSPO, and P&O. MPP and GMPP are accomplished in less than 3.8 ms and 10 ms, respectively. Based on the results presented, the LRMRAC controller appears to be a promising technique for MPPT in a PV system.

摘要:In this paper, load frequency control is performed for a two-area power system incorporating a high penetration of renewable energy sources. A droop controller for a type 3 wind turbine is used to extract the stored kinetic energy from the rotating masses during sudden load disturbances. An auxiliary storage controller is applied to achieve effective frequency response. The coot optimization algorithm (COA) is applied to allocate the optimum parameters of the fractional-order proportional integral derivative (FOPID), droop and auxiliary storage controllers. The fitness function is represented by the summation of integral square deviations in tie line power, and Areas 1 and 2 frequency errors. The robustness of the COA is proven by comparing the results with benchmarked optimizers including: atomic orbital search, honey badger algorithm, water cycle algorithm and particle swarm optimization. Performance assessment is confirmed in the following four scenarios: (i) optimization while including PID controllers; (ii) optimization while including FOPID controllers; (iii) validation of COA results under various load disturbances; and (iv) validation of the proposed controllers under varying weather conditions.

摘要:This paper demonstrates the controlling abilities of a large PV-farm as a Solar-PV inverter for mitigating the chaotic electrical, electromechanical, and torsional oscillations including Subsynchronous resonance in a turbogenerator-based power system. The oscillations include deviations in the machine speed, rotor angle, voltage fluctuations (leading to voltage collapse), and torsional modes. During the night with no solar power generation, the PV-plant switches to PV-STATCOM mode and works as a Solar-PV inverter at its full capacity to attenuate the oscillations. During full sun in the daytime, on any fault detection, the PV-plant responds instantly and stops generating power to work as a Solar-PV inverter. The PV-farm operates in the same mode until the oscillations are fully alleviated. This paper manifests the control of the DC-link capacitor voltage of the Solar-PV inverter with a bacterial foraging optimization-based intelligent maximum power point tracking controller for the optimal control of active and reactive power. Kundur’s multi-machine model aggregated with PV-plant is modeled in the Matlab/Simulink environment to examine the rotor swing deviations with associated shaft segments. The results for different test cases of interest demonstrate the positive outcomes of deploying large PV-farms as a smart PV-STATCOM for controlling power system oscillations.