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
With the growing demand for precise voltage adjustment and reactive regulation,the frequent operation of on-load tap changers(OLTCs)in oil-immersed systems has led to increased erosion of switch contacts by arcs durin...With the growing demand for precise voltage adjustment and reactive regulation,the frequent operation of on-load tap changers(OLTCs)in oil-immersed systems has led to increased erosion of switch contacts by arcs during the switching process.This erosion causes significant wear on the contacts,thereby reducing their lifespan.Therefore,the present study aims to investigate the behavior and mechanism of arc erosion on contact surfaces in oil-immersed OLTCs.To achieve this,a self-designed friction and wear test device for OLTC contacts was utilized to conduct experiments at various sliding speeds and contact pressures.Additionally,finite element analysis was employed to validate the experimental results regarding the influence of sliding speed on arc energy.The surface morphology of the contacts was observed using an optical microscope.The findings revealed that as the sliding speed increased,the arc energy,arc initiation rate,and contact resistance initially exhibited an upward trend,then decreased,and eventually increased again.The minimum values were observed at a sliding speed of 90 mm/s.Moreover,the arc energy,arc initiation rate,and contact resistance decreased gradually as the contact pressure increased.After reaching a contact pressure of 1.5 N,the variation in the arc energy stabilized.At lower contact pressures,arc erosion dominated the wear on the contact surface.However,at higher contact pressures,the wear transitioned from predominantly arc erosion to a combination of mechanical wear and arc erosion.In summary,experimental and analytical investigations provided insights into the effects of sliding speed and contact pressure on the behavior of arc erosion,contact resistance,and surface damage of OLTC contacts in oil-immersed systems.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
风电功率快速变化导致电压波动频繁且幅度较大.有载调压变压器(on-load tap changer,简称OLTC)通过改变无功分布实现调压,无需新增投资.普通变比灵敏度算法未考虑变比的离散约束,所得灵敏度不很准确,用于指导OLTC变比调节存在误差.采用...风电功率快速变化导致电压波动频繁且幅度较大.有载调压变压器(on-load tap changer,简称OLTC)通过改变无功分布实现调压,无需新增投资.普通变比灵敏度算法未考虑变比的离散约束,所得灵敏度不很准确,用于指导OLTC变比调节存在误差.采用二进制编码,将变比转化为0-1变量的线性组合,引入NCP函数将0-1变量连续化,提出基于NCP函数的连续化变比灵敏度算法,以应用于风电系统电压控制.探讨分析影响OLTC变比调节的因素.算例分析表明该文算法是有效可行的.展开更多
有载分接开关(on-load tap changer,OLTC)的机械故障声纹在线监测技术逐步得到应用,为消除OLTC声纹在线监测过程中外界环境干扰导致的误动,提出一种基于混合倒谱系数与卷积神经网络(convolutional neural network,CNN)的OLTC声音辨识方...有载分接开关(on-load tap changer,OLTC)的机械故障声纹在线监测技术逐步得到应用,为消除OLTC声纹在线监测过程中外界环境干扰导致的误动,提出一种基于混合倒谱系数与卷积神经网络(convolutional neural network,CNN)的OLTC声音辨识方法。首先通过现场采集与搭建试验平台的方式构建OLTC声信号数据集,并将变电站采集的环境声数据与ESC-50数据集共同构建成环境声数据集;其次,根据OLTC的声信号分布特性,采用梅尔倒谱系数、伽马通滤波倒谱系数、幂律归一化倒谱系数组成的混合倒谱对原始信号进行降维预处理,提升后续识别速度;最后,引入CNN通过超参数调整和网络结构优化设计构建声音辨识模型,实现OLTC与环境干扰的声信号辨识。结果表明,该方法在辨识OLTC与环境干扰声音方面具有较高的准确率与较快的计算速率。展开更多
有载分接开关(on-load tap changer,OLTC)是变压器实现有载调压的关键部件,具有复杂的机电结构。基于振动信号的OLTC机械故障诊断目前存在样本标记难度高而难以有效训练的难题。文中提出一种基于贝叶斯优化和卷积算子改进的阶梯网络(Bay...有载分接开关(on-load tap changer,OLTC)是变压器实现有载调压的关键部件,具有复杂的机电结构。基于振动信号的OLTC机械故障诊断目前存在样本标记难度高而难以有效训练的难题。文中提出一种基于贝叶斯优化和卷积算子改进的阶梯网络(Bayesian optimization-convolutional ladder networks,BO-ConvLN),可在少标签情况下提高OLTC机械故障诊断的精度。首先,引入阶梯网络对振动信号进行半监督学习,充分利用大量无标签样本的潜在信息对特征提取过程进行指导,提升少标签情况下阶梯网络的诊断性能。然后,用卷积算子替代阶梯网络中的全连接形式的线性变换,增强阶梯网络对非平稳振动信号的特征提取能力。在此基础上,借助贝叶斯优化对阶梯网络高维超参数进行寻优,在有限时间成本下显著提升了模型的诊断精度。实验结果显示,在仅有40个标签的情况下,对传动卡涩、芯子润滑不足、顶盖松动3类故障的诊断精度达91.67%,证明了BO-ConvLN在故障诊断中的有效性。展开更多
变压器有载调压开关在维护电网正常工作中尤为关键,如使负荷中心电压保持稳定、调整无功潮流、提高电网调度灵活性等,而在线检测有载调压开关(On-Load Tap Changer,OLTC)的运转性能,对确保该设备可靠性、稳定性以及安全性等具有至关重...变压器有载调压开关在维护电网正常工作中尤为关键,如使负荷中心电压保持稳定、调整无功潮流、提高电网调度灵活性等,而在线检测有载调压开关(On-Load Tap Changer,OLTC)的运转性能,对确保该设备可靠性、稳定性以及安全性等具有至关重要的影响。从变压器有载调压开关的主要故障原因展开分析,同时研究其故障诊断新技术,以此为推动电力系统正常工作给予强有力支撑。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With the growing demand for precise voltage adjustment and reactive regulation,the frequent operation of on-load tap changers(OLTCs)in oil-immersed systems has led to increased erosion of switch contacts by arcs during the switching process.This erosion causes significant wear on the contacts,thereby reducing their lifespan.Therefore,the present study aims to investigate the behavior and mechanism of arc erosion on contact surfaces in oil-immersed OLTCs.To achieve this,a self-designed friction and wear test device for OLTC contacts was utilized to conduct experiments at various sliding speeds and contact pressures.Additionally,finite element analysis was employed to validate the experimental results regarding the influence of sliding speed on arc energy.The surface morphology of the contacts was observed using an optical microscope.The findings revealed that as the sliding speed increased,the arc energy,arc initiation rate,and contact resistance initially exhibited an upward trend,then decreased,and eventually increased again.The minimum values were observed at a sliding speed of 90 mm/s.Moreover,the arc energy,arc initiation rate,and contact resistance decreased gradually as the contact pressure increased.After reaching a contact pressure of 1.5 N,the variation in the arc energy stabilized.At lower contact pressures,arc erosion dominated the wear on the contact surface.However,at higher contact pressures,the wear transitioned from predominantly arc erosion to a combination of mechanical wear and arc erosion.In summary,experimental and analytical investigations provided insights into the effects of sliding speed and contact pressure on the behavior of arc erosion,contact resistance,and surface damage of OLTC contacts in oil-immersed systems.
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。
文摘风电功率快速变化导致电压波动频繁且幅度较大.有载调压变压器(on-load tap changer,简称OLTC)通过改变无功分布实现调压,无需新增投资.普通变比灵敏度算法未考虑变比的离散约束,所得灵敏度不很准确,用于指导OLTC变比调节存在误差.采用二进制编码,将变比转化为0-1变量的线性组合,引入NCP函数将0-1变量连续化,提出基于NCP函数的连续化变比灵敏度算法,以应用于风电系统电压控制.探讨分析影响OLTC变比调节的因素.算例分析表明该文算法是有效可行的.
文摘有载分接开关(on-load tap changer,OLTC)的机械故障声纹在线监测技术逐步得到应用,为消除OLTC声纹在线监测过程中外界环境干扰导致的误动,提出一种基于混合倒谱系数与卷积神经网络(convolutional neural network,CNN)的OLTC声音辨识方法。首先通过现场采集与搭建试验平台的方式构建OLTC声信号数据集,并将变电站采集的环境声数据与ESC-50数据集共同构建成环境声数据集;其次,根据OLTC的声信号分布特性,采用梅尔倒谱系数、伽马通滤波倒谱系数、幂律归一化倒谱系数组成的混合倒谱对原始信号进行降维预处理,提升后续识别速度;最后,引入CNN通过超参数调整和网络结构优化设计构建声音辨识模型,实现OLTC与环境干扰的声信号辨识。结果表明,该方法在辨识OLTC与环境干扰声音方面具有较高的准确率与较快的计算速率。
文摘变压器有载调压开关在维护电网正常工作中尤为关键,如使负荷中心电压保持稳定、调整无功潮流、提高电网调度灵活性等,而在线检测有载调压开关(On-Load Tap Changer,OLTC)的运转性能,对确保该设备可靠性、稳定性以及安全性等具有至关重要的影响。从变压器有载调压开关的主要故障原因展开分析,同时研究其故障诊断新技术,以此为推动电力系统正常工作给予强有力支撑。
