The continuous operation of On-Load Tap-Changers (OLTC) is essential for maintaining stable voltage levels in power transmission and distribution systems. Timely fault detection in OLTC is essential for preventing maj...The continuous operation of On-Load Tap-Changers (OLTC) is essential for maintaining stable voltage levels in power transmission and distribution systems. Timely fault detection in OLTC is essential for preventing major failures and ensuring the reliability of the electrical grid. This research paper proposes an innovative approach that combines voiceprint detection using MATLAB analysis for online fault monitoring of OLTC. By leveraging advanced signal processing techniques and machine learning algorithms in MATLAB, the proposed method accurately detects faults in OLTC, providing real-time monitoring and proactive maintenance strategies.展开更多
Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utili...Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utilizing the reactive power capability of PV inverters to mitigate voltage deviations is being promoted.In recent years,droop control of inverter-based distributed energy resources has emerged as an essential tool for use in this study.The participation of PV systems in voltage regulation and its coordination with existing controllers,such as on-load tap changers,is paramount for controlling the voltage within specified limits.In this work,control strategies are presented that can be coordinated with the existing controls in a distributed manner.The effectiveness of the proposed method was demonstrated through simulation results on a distribution system.展开更多
柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有...柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有载分接开关调压带来的诸多问题,文中提出基于全电力电子有载分接开关的快速电磁式HUPFC。首先,针对其工作特性进行研究,并提出抑制开关切换过程中产生过压的方法。然后,根据不对称级电压Sen变压器的工作点合成方式存在自由度,实现一种开关切换次数最少的抽头选择策略,并给出从潮流指令改变到开关切换调压的详细步骤。最后,在Simulink中搭建220 kV双回线路仿真模型,对比快速电磁式HUPFC与传统HUPFC的潮流调节过程及结果。结果表明,全电力电子开关在响应速度和降低调节过程中的功率波动等方面更具优势,验证了快速电磁式HUPFC的可行性。展开更多
变压器有载分接开关(on-load top changer,OLTC)的主要故障类型是机械故障,现有大多数研究仅诊断切换开关故障,难以辨识影响换档全过程的传动机构故障。为准确诊断切换开关与传动机构故障,该文提出一种基于换档全过程振动强度的OLTC机...变压器有载分接开关(on-load top changer,OLTC)的主要故障类型是机械故障,现有大多数研究仅诊断切换开关故障,难以辨识影响换档全过程的传动机构故障。为准确诊断切换开关与传动机构故障,该文提出一种基于换档全过程振动强度的OLTC机械故障诊断方法。首先,将多通道切换开关振动爆发数据转换为时域波形图输入改进的卷积神经网络(convolutional neural network,CNN),以获取池化层特征。然后,提出换档全过程振动强度特征,将换档全过程振动信号划分为多个区间,统计各区间中幅值超过阈值的点数,以表征各时间段平均振动强度。最后,提出一种新的特征处理方法改变以上两种特征的相对大小,并融合两种特征训练分类器诊断机械故障类型。实例分析表明:相比于现有OLTC机械故障诊断方法,所提方法能有效辨识传动机构故障,进一步提升对切换开关故障的诊断精度,具有较强的鲁棒性与泛用性,可为OLTC机械故障诊断研究提供新的思路。展开更多
机械故障是变压器有载调压分接开关(On-Load Tap Changer,OLTC)的主要故障类型,因此监测其机械运行性能对保障电力系统安全、稳定与可靠运行具有重要意义。区别于传统的时、频域分析方法,本文提出了一种基于多维坐标空间提取相轨图几何...机械故障是变压器有载调压分接开关(On-Load Tap Changer,OLTC)的主要故障类型,因此监测其机械运行性能对保障电力系统安全、稳定与可靠运行具有重要意义。区别于传统的时、频域分析方法,本文提出了一种基于多维坐标空间提取相轨图几何特征的方法,通过定义相点空间分布系数以定量描述开关操作时不同振动模式的特征变化,从混沌动力学角度为机械状态监测与故障诊断提供了一项新的科学依据。对现场监测数据的分析表明,文中提出的特征提取方法是可行的。展开更多
为对变压器有载分接开关机械故障进行诊断,提出一种结合奇异值分解SVD(singular value decompo-sition)消噪与小波包WP(wavelet packet)消噪的信号特征提取方法。首先对信号进行小波包消噪,然后进行SVD二次消噪,将消噪信号进行经验模态...为对变压器有载分接开关机械故障进行诊断,提出一种结合奇异值分解SVD(singular value decompo-sition)消噪与小波包WP(wavelet packet)消噪的信号特征提取方法。首先对信号进行小波包消噪,然后进行SVD二次消噪,将消噪信号进行经验模态分解EMD(empirical mode decomposition),对得出的各阶固有模态分量进行希尔伯特-黄变换HHT(Hilbert-Huang transform)。数值仿真表明基于WP_SVD降噪的信号特征提取比小波包或SVD单独降噪的信号特征提取方法有效,并成功地将该方法应用到分接开关实际振动信号分析中。展开更多
为提高对真空灭弧式有载分接开关(on-loadtapchanger,OLTC)运行特性的认知水平,掌握真空灭弧式OLTC切换过程中的振动特性,提高其运行可靠性,基于改进密度的含噪声空间聚类(density-based spatial clustering of applications with noise...为提高对真空灭弧式有载分接开关(on-loadtapchanger,OLTC)运行特性的认知水平,掌握真空灭弧式OLTC切换过程中的振动特性,提高其运行可靠性,基于改进密度的含噪声空间聚类(density-based spatial clustering of applications with noise, DBSCAN)算法对比分析了真空与油灭弧式OLTC切换过程中的振动信号。即通过合理设定距离阈值和点数阈值对振动信号进行了DBSCAN聚类,然后根据聚类结果定义了动作点数和离散点数来描述OLTC的振动特性。对SHZV型真空OLTC与M型OLTC切换过程中振动信号的分析表明:改进DBSCAN聚类算法能有效描述OLTC振动信号的脉冲分布特征,相对于油灭弧OLTC,真空灭弧式OLTC切换过程中振动信号的动作点数和离散点数均大于油灭弧式OLTC,反映了真空灭弧式OLTC振动信号多脉冲离散分布的特点。研究结果可为基于振动分析法的真空OLTC机械状态监测技术提供参考。展开更多
文摘The continuous operation of On-Load Tap-Changers (OLTC) is essential for maintaining stable voltage levels in power transmission and distribution systems. Timely fault detection in OLTC is essential for preventing major failures and ensuring the reliability of the electrical grid. This research paper proposes an innovative approach that combines voiceprint detection using MATLAB analysis for online fault monitoring of OLTC. By leveraging advanced signal processing techniques and machine learning algorithms in MATLAB, the proposed method accurately detects faults in OLTC, providing real-time monitoring and proactive maintenance strategies.
基金by a project under the scheme entitled“Developing Policies&Adaptation Strategies to Climate Change in the Baltic Sea Region”(ASTRA),Project No.ASTRA6-4(2014-2020.4.01.16-0032).
文摘Decreasing costs and favorable policies have resulted in increased penetration of solar photovoltaic(PV)power generation in distribution networks.As the PV systems penetration is likely to increase in the future,utilizing the reactive power capability of PV inverters to mitigate voltage deviations is being promoted.In recent years,droop control of inverter-based distributed energy resources has emerged as an essential tool for use in this study.The participation of PV systems in voltage regulation and its coordination with existing controllers,such as on-load tap changers,is paramount for controlling the voltage within specified limits.In this work,control strategies are presented that can be coordinated with the existing controls in a distributed manner.The effectiveness of the proposed method was demonstrated through simulation results on a distribution system.
文摘柔性交流输电系统(flexible alternative current transmission systems,FACTS)装置如混合式统一潮流控制器(hybrid unified power flow controller,HUPFC)可调节线路潮流,有效提升输电网络的传输容量。为解决传统HUPFC中使用机械式有载分接开关调压带来的诸多问题,文中提出基于全电力电子有载分接开关的快速电磁式HUPFC。首先,针对其工作特性进行研究,并提出抑制开关切换过程中产生过压的方法。然后,根据不对称级电压Sen变压器的工作点合成方式存在自由度,实现一种开关切换次数最少的抽头选择策略,并给出从潮流指令改变到开关切换调压的详细步骤。最后,在Simulink中搭建220 kV双回线路仿真模型,对比快速电磁式HUPFC与传统HUPFC的潮流调节过程及结果。结果表明,全电力电子开关在响应速度和降低调节过程中的功率波动等方面更具优势,验证了快速电磁式HUPFC的可行性。
文摘变压器有载分接开关(on-load top changer,OLTC)的主要故障类型是机械故障,现有大多数研究仅诊断切换开关故障,难以辨识影响换档全过程的传动机构故障。为准确诊断切换开关与传动机构故障,该文提出一种基于换档全过程振动强度的OLTC机械故障诊断方法。首先,将多通道切换开关振动爆发数据转换为时域波形图输入改进的卷积神经网络(convolutional neural network,CNN),以获取池化层特征。然后,提出换档全过程振动强度特征,将换档全过程振动信号划分为多个区间,统计各区间中幅值超过阈值的点数,以表征各时间段平均振动强度。最后,提出一种新的特征处理方法改变以上两种特征的相对大小,并融合两种特征训练分类器诊断机械故障类型。实例分析表明:相比于现有OLTC机械故障诊断方法,所提方法能有效辨识传动机构故障,进一步提升对切换开关故障的诊断精度,具有较强的鲁棒性与泛用性,可为OLTC机械故障诊断研究提供新的思路。
文摘机械故障是变压器有载调压分接开关(On-Load Tap Changer,OLTC)的主要故障类型,因此监测其机械运行性能对保障电力系统安全、稳定与可靠运行具有重要意义。区别于传统的时、频域分析方法,本文提出了一种基于多维坐标空间提取相轨图几何特征的方法,通过定义相点空间分布系数以定量描述开关操作时不同振动模式的特征变化,从混沌动力学角度为机械状态监测与故障诊断提供了一项新的科学依据。对现场监测数据的分析表明,文中提出的特征提取方法是可行的。
文摘为提高对真空灭弧式有载分接开关(on-loadtapchanger,OLTC)运行特性的认知水平,掌握真空灭弧式OLTC切换过程中的振动特性,提高其运行可靠性,基于改进密度的含噪声空间聚类(density-based spatial clustering of applications with noise, DBSCAN)算法对比分析了真空与油灭弧式OLTC切换过程中的振动信号。即通过合理设定距离阈值和点数阈值对振动信号进行了DBSCAN聚类,然后根据聚类结果定义了动作点数和离散点数来描述OLTC的振动特性。对SHZV型真空OLTC与M型OLTC切换过程中振动信号的分析表明:改进DBSCAN聚类算法能有效描述OLTC振动信号的脉冲分布特征,相对于油灭弧OLTC,真空灭弧式OLTC切换过程中振动信号的动作点数和离散点数均大于油灭弧式OLTC,反映了真空灭弧式OLTC振动信号多脉冲离散分布的特点。研究结果可为基于振动分析法的真空OLTC机械状态监测技术提供参考。
