Electric Power Systems Research最新文献_第7页

Optimal operation of three-phase unbalanced active distribution system based on semidefinite relaxation and convex-concave procedure 基于半无限松弛和凸凹程序的三相不平衡有源配电系统优化运行

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-10 DOI: 10.1016/j.epsr.2024.111128

Yidan Zhou, Yao Zhang, Qianhao Sun, Jiale Wang, Yingjie Zhao, Jianxue Wang

The three-phase distribution optimal power flow (D-OPF) problem has attracted much attention in recent years due to practical requirements for managing distributed energy resources and multi-energy customers in unbalanced active distribution systems. To deal with the strong nonconvexity of the three-phase OPF problem, this paper develops the semidefinite programming (SDP) formulation of three-phase OPF problems considering the mutual coupling in multi-phase networks. Instead of directly dropping the rank-one constraints, a sequential convex optimization algorithm based on the convex-concave procedure (CCP) is proposed for recovering a feasible and optimal solution of three-phase power flow. The proposed iterative algorithm not only has high computational efficiency but also guarantees the optimality when the semidefinite relaxation or second-order cone relaxation method is inexact. Case studies on various IEEE testing distribution systems verify that the proposed algorithm recovers the feasible and optimal power flow solution. It also exhibits a relatively low number of iterations and short solving time in large-scale IEEE testing systems.

近年来，由于不平衡有功配电系统中分布式能源资源和多能源客户管理的实际需求，三相配电优化功率流（D-OPF）问题备受关注。针对三相 OPF 问题的强非凸性，本文开发了考虑多相网络中相互耦合的三相 OPF 问题的半有限编程（SDP）公式。本文没有直接放弃秩一约束，而是提出了一种基于凸凹过程（CCP）的顺序凸优化算法，用于恢复三相功率流的可行最优解。所提出的迭代算法不仅计算效率高，而且在半有限松弛法或二阶锥松弛法不精确时也能保证最优性。对各种 IEEE 测试配电系统的案例研究验证了所提算法能恢复可行的最优功率流解决方案。在大规模 IEEE 测试系统中，该算法的迭代次数相对较少，求解时间较短。

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引用次数: 0

A hybrid stochastic-robust bidding model for wind-storage system in day-ahead market considering risk preference 考虑风险偏好的日前市场风力存储系统随机-稳健混合投标模型

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-10 DOI: 10.1016/j.epsr.2024.111148

Sashuang Sun , YouBo Liu , Zhiyuan Tang , Mengfu Tu , Xili Du , Junyong Liu

In this paper, a novel hybrid stochastic-robust bidding model for a wind-storage system in the day-ahead (DA) market considering risk preferences is proposed. In the proposed scheme, the uncertainties of wind power and DA electricity price are firstly accounted for through stochastic optimization (SO) and robust optimization (RO) models. Then, to combine the advantages of both SO and RO models, based on the Hurwicz optimistic coefficient, a hybrid stochastic-robust bidding model is formulated for wind-storage systems, where wind farm bidders can select bidding strategies with different risk levels. Additionally, to reflect a more realistic operating cost of Energy Storage System (ESS), the ESS life degradation model based on equivalent full cycle counts is embedded into this hybrid model. To make the proposed non-convex hybrid bidding model computationally tractable, strong duality theory and piecewise linear functions are employed to transform it into a mixed integer linear programming (MILP) problem, which can be efficiently solved with the off-the-shelf optimization software. The simulation results demonstrate that the proposed bidding model effectively handles various scenarios and enables the selection of appropriate strategies under different risk preferences.

本文提出了一种考虑风险偏好的新型混合随机-稳健竞价模型，用于日前（DA）市场的风力存储系统。在所提出的方案中，首先通过随机优化（SO）和稳健优化（RO）模型考虑了风力发电和日前电价的不确定性。然后，结合随机优化模型和鲁棒优化模型的优点，基于 Hurwicz 乐观系数，为风光储系统制定了随机-鲁棒混合投标模型，风电场投标人可选择不同风险水平的投标策略。此外，为了更真实地反映储能系统（ESS）的运营成本，该混合模型还嵌入了基于等效全周期计数的ESS寿命衰减模型。为使所提出的非凸混合投标模型在计算上具有可操作性，我们采用了强对偶理论和片断线性函数，将其转化为混合整数线性规划（MILP）问题，该问题可通过现成的优化软件高效解决。仿真结果表明，所提出的投标模型能有效处理各种情况，并能在不同风险偏好下选择适当的策略。

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引用次数: 0

Failure evaluation of outdoor polymeric insulators based on statistical condition-assessment methods 基于统计条件评估方法的户外聚合绝缘子故障评估

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-09 DOI: 10.1016/j.epsr.2024.111134

Navid Fahimi , Mohammad Goudarzi , Amir Abbas Shayegani-Akmal

Field aging of outdoor polymeric insulators results in unscheduled outages in power systems particularly in harsh climate conditions. In this paper, a strategic maintenance framework is proposed in order to prevent overhead line outages. The presented scheme is based on condition assessment of the real aged polymeric insulators. Data of tensile test, hardness test, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) are used to extract critical features of the aged samples based on classification of fuzzy c-means clustering. Then, a lifetime prediction analysis is done based on Cox hazards analysis to develop further maintenance strategy. The proposed model is validated through numerical analyses on polymeric insulators for various validation evaluations including pollution severity analysis and hydrophobicity class (HC) measurement. Obtained results verify accuracy of the intelligent model to predict lifetime of the aged polymeric insulators. The presented strategic framework can be effectively applied to online monitoring, condition assessment and preventive maintenance programs of the power system utilities.

户外聚合绝缘子的现场老化会导致电力系统意外停电，尤其是在恶劣的气候条件下。本文提出了一个战略性维护框架，以防止架空线路停电。所提出的方案以实际老化聚合绝缘子的状态评估为基础。利用拉伸试验、硬度试验、热重分析（TGA）和傅立叶变换红外光谱（FTIR）的数据，在模糊 c-means 聚类的基础上提取老化样品的关键特征。然后，基于 Cox 危险分析进行寿命预测分析，以制定进一步的维护策略。通过对聚合绝缘体进行数值分析，对提出的模型进行了验证，包括污染严重程度分析和疏水性等级（HC）测量等各种验证评估。获得的结果验证了智能模型预测老化聚合绝缘子寿命的准确性。所提出的战略框架可有效应用于电力系统公用事业的在线监测、状态评估和预防性维护计划。

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引用次数: 0

Online DMD-based Kalman filter for current sensor fault-tolerant control of MMC-HVDC transmission systems 基于 DMD 的在线卡尔曼滤波器，用于 MMC-HVDC 输电系统的电流传感器容错控制

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-08 DOI: 10.1016/j.epsr.2024.111144

Yuxi Liu , Yuexi Yang , Xiao Zhou , Yang Liu , Q.H. Wu

With the growing application of modular multilevel converter based high-voltage direct current transmission (MMC-HVDC), the sensor fault-tolerant capability in modular multilevel converters has become critical. This paper aims to boost the sensor fault-tolerant performance of the MMC-HVDC systems using advanced data-driven techniques. A novel online dynamic mode decomposition based Kalman filter (ODMDKF) is designed for fault detection and control reconfiguration. Besides, a modified dual-check fault detection module based on local outlier factor algorithm is proposed to reduce false alarm rate. Simulation studies are conducted on a modified IEEE 9-bus system with MMC-HVDC transmission lines. The results indicate that the proposed sensor fault-tolerant control method can ensure the continuous operation of the MMC-HVDC systems under the condition of three types of current sensor faults and its fault-tolerant capability is better than that of extended Kalman filter-based fault-tolerant control method.

随着基于模块化多电平转换器的高压直流输电（MMC-HVDC）的应用日益广泛，模块化多电平转换器的传感器容错能力变得至关重要。本文旨在利用先进的数据驱动技术提高 MMC-HVDC 系统的传感器容错性能。本文设计了一种基于卡尔曼滤波器的新型在线动态模式分解（ODMDKF），用于故障检测和控制重新配置。此外，还提出了一种基于局部离群因子算法的改进型双检查故障检测模块，以降低误报率。仿真研究是在带 MMC-HVDC 输电线路的改进型 IEEE 9 总线系统上进行的。结果表明，所提出的传感器容错控制方法可确保 MMC-HVDC 系统在三种电流传感器故障情况下连续运行，其容错能力优于基于扩展卡尔曼滤波器的容错控制方法。

引用次数: 0

Ex post conditions for the exactness of optimal power flow conic relaxations 最优功率流圆锥松弛的精确性的事后条件

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-08 DOI: 10.1016/j.epsr.2024.111130

Jean-Luc Lupien, Antoine Lesage-Landry

Convex relaxations of the optimal power flow (OPF) problem provide an efficient alternative to solving the intractable alternating current (AC) optimal power flow. The conic subset of OPF convex relaxations, in particular, greatly accelerate resolution while leading to high-quality approximations that are exact in several scenarios. However, the sufficient conditions guaranteeing exactness are stringent, e.g., requiring radial topologies. In this short communication, we present two equivalent ex post conditions for the exactness of any conic relaxation of the OPF. These rely on obtaining either a rank-1 voltage matrix or self-coherent cycles. Instead of relying on sufficient conditions a priori, satisfying one of the presented ex post conditions acts as an exactness certificate for the computed solution. The operator can therefore obtain an optimality guarantee when solving a conic relaxation even when a priori exactness requirements are not met. Finally, we present numerical examples from the MATPOWER library where the ex post conditions hold even though the exactness sufficient conditions do not, thereby illustrating the use of the conditions.

最优功率流（OPF）问题的凸松弛为解决棘手的交流（AC）最优功率流问题提供了一种高效的替代方法。尤其是 OPF 凸松弛的圆锥子集，大大加快了求解速度，同时带来了高质量的近似值，在多种情况下都是精确的。然而，保证精确性的充分条件非常苛刻，例如需要径向拓扑结构。在这篇短文中，我们为 OPF 的任何圆锥松弛的精确性提出了两个等效的事后条件。这两个条件依赖于获得秩-1 电压矩阵或自相干循环。与其依赖先验充分条件，满足其中一个事后条件可作为计算解的精确性证书。因此，即使不满足先验精确性要求，算子在求解圆锥松弛时也能获得最优保证。最后，我们介绍了 MATPOWER 库中的一些数值示例，在这些示例中，即使不满足精确性充分条件，事后条件也能成立，从而说明了这些条件的用途。

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引用次数: 0

Faulty section location method for high impedance grounding fault in resonant grounding system based on discrete Fréchet distance 基于离散弗雷谢特距离的谐振接地系统高阻抗接地故障的故障段定位方法

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-08 DOI: 10.1016/j.epsr.2024.111147

Honglu Xu , Xinhui Zhang , Haoyue Sun , Wenhao Wu , Jiaxi Zhu , Fuqian Wang

When a High Impedance Fault (HIF) occurs in a resonant grounding system, the differentiation of the current flowing upstream and downstream of the fault point is inconspicuous due to the weak electrical signal. This paper proposes a faulty section location approach based on Discrete Fréchet Distance (DFD) to address this issue. Initially, taking the zero-sequence current as the characteristic quantity, the instantaneous value of the zero-sequence current at each sampling point and its previous sampling moments are accumulated to amplify the fault signal, and furthermore to obtain the cumulative waveform of the zero-sequence current at each monitoring point. The DFD values between the cumulative waveforms of zero-sequence currents flowing through each section are also calculated. For a branchless section, if the Coefficient of Variation (CV) of the DFD in each section does not exceed the threshold value, it is identified as an end-of-line fault, otherwise, the section with the maximum DFD is identified as a faulty section. For a section with branches, the branching coefficient is calculated to determine whether it is a faulty section or not. Finally, MATLAB/Simulink simulation results and field-recorded data demonstrate the validity and robustness of the approach under various fault conditions, despite the connection of Distributed Generators (DGs).

当谐振接地系统发生高阻抗故障（HIF）时，由于电信号较弱，故障点上下游电流的区分并不明显。本文提出了一种基于离散弗雷谢特距离（DFD）的故障段定位方法来解决这一问题。首先，以零序电流为特征量，累计每个采样点的零序电流瞬时值及其之前的采样时刻，放大故障信号，进而得到每个监测点的零序电流累积波形。同时计算流经每个区段的零序电流累积波形之间的 DFD 值。对于无分支区段，如果每个区段的 DFD 变差系数（CV）不超过阈值，则将其识别为线路末端故障，否则将 DFD 最大的区段识别为故障区段。对于有分支的区段，通过计算分支系数来确定其是否为故障区段。最后，MATLAB/Simulink 仿真结果和现场记录数据证明了该方法在各种故障条件下的有效性和稳健性，尽管连接了分布式发电机（DG）。

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引用次数: 0

Data-model driven probability model of branch power flow for distribution networks and its application to analysis of overload and line loss 数据模型驱动的配电网分支电力流概率模型及其在过载和线损分析中的应用

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-07 DOI: 10.1016/j.epsr.2024.111140

Ren Zhang , Haoming Liu , Jian Wang , Haiqing Cai , Haohan Gu , Wei Chen , Zhihao Chen

The fluctuation of highly penetrated distributed generations (DGs) in distribution networks (DNs) increases branch overload risks, which makes the analysis uncertainty of branch power flow more complex. The probability analysis of branch power can grasp the power flow operation characteristics under uncertain conditions, which supports the power flow optimization management and ensures the safe and economic operation of DNs. Therefore, this paper proposes a data-model driven probability analysis method for branch power flow in DNs. An approximate branch power model is first derived to reveal the analytical relationship between branch power and node power. Then, based on the branch power approximation model and the forecasting error, the datasets of branch apparent power are constructed to capture the complex nonlinear characteristics of the power flow. The non-Gaussian distribution characteristics of branch apparent power and line loss are described by the optimal probability fitting method. Finally, the probability level of branch overload is evaluated and the probability distribution of line loss is analyzed. The case studies demonstrate that the branch power approximation model is highly accurate, and the probability distribution of the branch apparent power presents different characteristics. The proposed method can quickly and accurately calculate the branch overload probability level.

配电网（DN）中高渗透率分布式发电（DG）的波动增加了支路过载风险，使得支路功率流的不确定性分析变得更加复杂。通过对支路功率的概率分析，可以掌握不确定条件下的功率流运行特性，为功率流优化管理提供支持，确保配电网的安全经济运行。因此，本文提出了一种数据模型驱动的 DNs 分支功率流概率分析方法。首先推导出近似的分支功率模型，揭示了分支功率与节点功率之间的分析关系。然后，基于支路功率近似模型和预测误差，构建支路视在功率数据集，以捕捉功率流的复杂非线性特征。支路视在功率和线路损耗的非高斯分布特征采用最优概率拟合方法进行描述。最后，评估了分支过载的概率水平，并分析了线路损耗的概率分布。案例研究表明，支路功率近似模型非常准确，支路视在功率的概率分布呈现出不同的特征。所提出的方法可以快速准确地计算出分支过载概率水平。

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引用次数: 0

Approximated Power Flow for AC Islanded Microgrids 交流孤岛式微电网的近似电力流

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-07 DOI: 10.1016/j.epsr.2024.111129

Elson N. M. Silva, Anselmo B. Rodrigues, Maria da Guia da Silva

This paper proposes a new approximated power flow method for islanded AC microgrids. The proposed linear power flow is based on the expansion and improvement of the well-known approximated model for voltage drop calculation in distribution networks based on power injections and the Zbus matrix. The accuracy of this conventional approximation has been improved through the following strategies: linearization based on warm-start and post-solution correction to include the imaginary part of complex voltages. Furthermore, droop controls were embedded into the original approximated model to consider the microgrids islanded operation. The accuracy of the proposed method was assessed using nonlinear optimization models. The tests results with 69 and 906 nodes microgrids demonstrated that the proposed approach is generally more accurate than existing approximated algorithms for solving power flow in islanded microgrids. Furthermore, a computational cost assessment of the proposed technique was performed using a Probabilistic Power Flow (PPF) based on Monte Carlo Simulation. The results revealed that the PPF based on the proposed approach can estimate probabilistic performance indices with high precision, but with reductions of 97% in CPU time.

本文为孤岛交流微电网提出了一种新的近似功率流方法。所提出的线性功率流是在众所周知的基于功率注入和 Zbus 矩阵的配电网电压降计算近似模型的基础上扩展和改进而来的。通过以下策略提高了传统近似模型的准确性：基于热启动的线性化和包含复数电压虚部的后求解修正。此外，还在原始近似模型中嵌入了降压控制，以考虑微电网的孤岛运行。利用非线性优化模型评估了所提方法的准确性。69 节点和 906 节点微电网的测试结果表明，在解决孤岛微电网的电力流问题上，所提出的方法总体上比现有的近似算法更准确。此外，还使用基于蒙特卡罗模拟的概率功率流（PPF）对所提技术进行了计算成本评估。结果表明，基于所提方法的 PPF 可以估算出高精度的概率性能指标，但 CPU 时间却减少了 97%。

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引用次数: 0

A hosting capacity based approach toward distribution system planning for high PV penetration 基于托管容量的配电系统规划方法，适用于光伏发电的高渗透率

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-05 DOI: 10.1016/j.epsr.2024.111138

Taís Tavares de Oliveira, Math H.J. Bollen, Nicholas Etherden

This paper presents an approach to estimate the hosting capacity for distribution networks considering the impact of PV penetration at different voltage levels. The estimation and the method were selected such that the results were most suitable for distribution system planning. A time-series based method was used as it covers significant aspects needed for prioritising network reinforcement. The MV background voltage was modelled varying in time, assuming the same penetration level in the other LV networks supplied by the same MV system. The hosting capacity is defined as the maximum acceptable PV size per customer for a given PV penetration. Based on the different possible combinations of PV location, the probability of overvoltage and overloading is used as a performance index. The planning risk is used as a limit for the performance criterion. The method can be automated for a large number of networks due to using an IEC 61970-based input format. It also enables linking DSO network models to customer smart metre databases. The severity and risks of limit violations are analysed with different metrics from the time-series simulations. The change in background voltage with increasing penetration is shown to impact the results significantly. When considering it, the estimated hosting capacity was reduced by 32 %, on average.

本文介绍了一种估算配电网承载能力的方法，其中考虑了不同电压等级下光伏渗透率的影响。估算结果和方法的选择以最适合配电系统规划为前提。本文采用了基于时间序列的方法，因为该方法涵盖了确定网络加固优先级所需的重要方面。中压背景电压的建模随时间而变化，假定由同一中压系统供电的其他低压网络的渗透水平相同。托管容量被定义为在给定光伏渗透率下每个用户可接受的最大光伏规模。根据光伏位置的不同可能组合，过压和过载的概率被用作性能指标。规划风险被用作性能标准的限制。由于使用了基于 IEC 61970 的输入格式，该方法可自动适用于大量网络。它还能将 DSO 网络模型与客户智能电表数据库连接起来。通过时间序列模拟的不同指标，对违反限值的严重性和风险进行了分析。随着渗透率的增加，背景电压的变化会对结果产生重大影响。考虑到这一点，估计的托管容量平均降低了 32%。

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引用次数: 0

Maximum power point tracking control of wind turbines based on speed hysteresis loop to reduce drive-train loads 基于速度滞后环的风力涡轮机最大功率点跟踪控制，以降低传动系统负荷

IF 3.3 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Electric Power Systems Research

Pub Date : 2024-10-05 DOI: 10.1016/j.epsr.2024.111110

Dandan Song , Minghui Yin , Zaiyu Chen , Lianjun Zhou , Yun Zou

By adding compensation torque based on the optimal torque, the torque compensation control method expands the unbalanced torque at varying wind speeds, thereby improving the maximum power point tracking (MPPT) performance of wind turbines (WT). However, while improving the wind energy capture efficiency, such methods will lead to drastic fluctuations of generator torque, resulting in significantly increased drive-train loads. To solve this problem, based on the amplitude-frequency characteristics analysis of the WT system transfer function, it is found rotor speed information can not only reflect the main trend of wind speed changes, but also has the characteristics of not being easily affected by the high-frequency component of wind speed. Therefore, setting compensation torque according to it can effectively alleviate the above phenomenon. On this basis, the MPPT control of WT based on speed hysteresis loop to reduce drive-train loads is proposed. The speed information is used to replace the torque information to set the compensation torque amplitude term, and the speed hysteresis loop is introduced to improve the design of the compensation torque symbol term, which can significantly decreased drive-train loads without compromising on power capture. Finally, the effectiveness of the proposed method is verified by the experiments.

通过在最佳转矩的基础上增加补偿转矩，转矩补偿控制方法扩大了不同风速下的不平衡转矩，从而改善了风力涡轮机（WT）的最大功率点跟踪（MPPT）性能。然而，这种方法在提高风能捕获效率的同时，也会导致发电机转矩剧烈波动，从而显著增加传动系统负载。为解决这一问题，根据风电机组系统传递函数的幅频特性分析，发现转子速度信息不仅能反映风速变化的主要趋势，还具有不易受风速高频分量影响的特点。因此，根据其设定补偿转矩可以有效缓解上述现象。在此基础上，提出了基于速度滞后环的风电机组 MPPT 控制，以降低传动系统负载。利用速度信息代替转矩信息来设置补偿转矩幅值项，并引入速度滞环来改进补偿转矩符号项的设计，从而在不影响功率捕获的情况下显著降低传动系统负载。最后，实验验证了所提方法的有效性。

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引用次数: 0