This paper presents a new earth-fault detection algorithm for unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm is based on capacitance calculation from transient im...This paper presents a new earth-fault detection algorithm for unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm is based on capacitance calculation from transient impedance and dominant transient frequency. The Discrete Fourier Transform （DFT） method is used to determine the dominant transient frequency. The values of voltage and current earth modes are calculated in the period of the dominant transient frequency, then the transient impedance can be determined, from which we can calculate the earth capacitance. The calculated capacitance gives an indication about if the feeder is faulted or not. The algorithm is less dependent on the fault resistance and the faulted feeder parameters; it mainly depends on the background network. The network is simulated by ATP/EMTP program. Several different fault conditions are covered in the simulation process, different fault inception angles, fault locations and fault resistances.展开更多
This paper presents a novel transient current differential algorithm for earth fault detection in unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm uses the transien...This paper presents a novel transient current differential algorithm for earth fault detection in unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm uses the transient residual currents, which are very sensitive for earth faults detection. The transient values of residual currents are calculated for each feeder in the network and used as an earth fault indicator. The flow of residual currents is investigated. It is found that the residual current for the faulted feeder is equal to the summation of all residual currents for all other healthy feedersl Based on this investigation, a differential technique is proposed. A percentage restrain performance is proposed to ensure the selectivity and security of the algorithm. The transient algorithm is very sensitive for earth fault incidence. To apply the proposed algorithm, the residual currents can be measured easily by one sensor for each feeder with no need to voltage measurement. The proposed algorithm is less dependent on the fault resistance and the faulted feeder parameters. The network is simulated by ATP/EMTP program. Different fault conditions are covered in the simulation process： different fault inception angles, fault locations and fault resistances.展开更多
The electrical energy produced must be consumed at the same time, hence the need to achieve a balance between supply and demand. Therefore, the production, transport, and distribution systems together constitute an el...The electrical energy produced must be consumed at the same time, hence the need to achieve a balance between supply and demand. Therefore, the production, transport, and distribution systems together constitute an electricity network. The distribution networks are designed to deliver energy to consumers. Unacceptable voltage drops are observed in the distribution networks of developing countries such as Burkina Faso. A study was carried out on the distribution network of the city of Bobo-Dioulasso in Burkina Faso. It allowed for experimentation with the “Megger MPQ1000” network analyzer to evaluate the quality of the voltage supplied to households. To this end, tests were carried out in a public distribution station and at a few subscribers in the Sarfalao district of the city of Bobo-Dioulasso. These tests were used to assess the percentage of voltage drops. These values, which are higher than 8% of the nominal voltage, are not regulatory. The load curves of the consumers in the district were also drawn. Indeed, the period of the high load is between 19:00 and 23:00 Local Time (LT), while the period of the medium and low load is between 00:00 and 18:00 LT.展开更多
现有深度多视图立体(MVS)方法将Transformer引入级联网络,以实现高分辨率深度估计,从而实现高精确度和完整度的三维重建结果。然而,基于Transformer的方法受计算成本的限制,无法扩展到更精细的阶段。为此,提出一种新颖的跨尺度Transfor...现有深度多视图立体(MVS)方法将Transformer引入级联网络,以实现高分辨率深度估计,从而实现高精确度和完整度的三维重建结果。然而,基于Transformer的方法受计算成本的限制,无法扩展到更精细的阶段。为此,提出一种新颖的跨尺度Transformer的MVS网络,在不增加额外计算的情况下处理不同阶段的特征表示。引入一种自适应匹配感知Transformer(AMT),在多个尺度上使用不同的交互式注意力组合。这种组合策略使所提网络能够捕捉图像内部的上下文信息,并增强图像之间的特征关系。此外,设计双特征引导聚合(DFGA),将粗糙的全局语义信息嵌入到更精细的代价体构建中,以进一步增强全局和局部特征的感知。同时,通过设计一种特征度量损失,用于评估变换前后的特征偏差,以减少特征错误匹配对深度估计的影响。实验结果表明,在DTU数据集中,所提网络的完整度和整体度量达到0.264、0.302,在Tanks and temples 2个大场景的重建平均值分别达到64.28、38.03。展开更多
文摘This paper presents a new earth-fault detection algorithm for unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm is based on capacitance calculation from transient impedance and dominant transient frequency. The Discrete Fourier Transform （DFT） method is used to determine the dominant transient frequency. The values of voltage and current earth modes are calculated in the period of the dominant transient frequency, then the transient impedance can be determined, from which we can calculate the earth capacitance. The calculated capacitance gives an indication about if the feeder is faulted or not. The algorithm is less dependent on the fault resistance and the faulted feeder parameters; it mainly depends on the background network. The network is simulated by ATP/EMTP program. Several different fault conditions are covered in the simulation process, different fault inception angles, fault locations and fault resistances.
文摘This paper presents a novel transient current differential algorithm for earth fault detection in unearthed （isolated） and compensated neutral medium voltage （MV） networks. The proposed algorithm uses the transient residual currents, which are very sensitive for earth faults detection. The transient values of residual currents are calculated for each feeder in the network and used as an earth fault indicator. The flow of residual currents is investigated. It is found that the residual current for the faulted feeder is equal to the summation of all residual currents for all other healthy feedersl Based on this investigation, a differential technique is proposed. A percentage restrain performance is proposed to ensure the selectivity and security of the algorithm. The transient algorithm is very sensitive for earth fault incidence. To apply the proposed algorithm, the residual currents can be measured easily by one sensor for each feeder with no need to voltage measurement. The proposed algorithm is less dependent on the fault resistance and the faulted feeder parameters. The network is simulated by ATP/EMTP program. Different fault conditions are covered in the simulation process： different fault inception angles, fault locations and fault resistances.
文摘The electrical energy produced must be consumed at the same time, hence the need to achieve a balance between supply and demand. Therefore, the production, transport, and distribution systems together constitute an electricity network. The distribution networks are designed to deliver energy to consumers. Unacceptable voltage drops are observed in the distribution networks of developing countries such as Burkina Faso. A study was carried out on the distribution network of the city of Bobo-Dioulasso in Burkina Faso. It allowed for experimentation with the “Megger MPQ1000” network analyzer to evaluate the quality of the voltage supplied to households. To this end, tests were carried out in a public distribution station and at a few subscribers in the Sarfalao district of the city of Bobo-Dioulasso. These tests were used to assess the percentage of voltage drops. These values, which are higher than 8% of the nominal voltage, are not regulatory. The load curves of the consumers in the district were also drawn. Indeed, the period of the high load is between 19:00 and 23:00 Local Time (LT), while the period of the medium and low load is between 00:00 and 18:00 LT.
文摘现有深度多视图立体(MVS)方法将Transformer引入级联网络,以实现高分辨率深度估计,从而实现高精确度和完整度的三维重建结果。然而,基于Transformer的方法受计算成本的限制,无法扩展到更精细的阶段。为此,提出一种新颖的跨尺度Transformer的MVS网络,在不增加额外计算的情况下处理不同阶段的特征表示。引入一种自适应匹配感知Transformer(AMT),在多个尺度上使用不同的交互式注意力组合。这种组合策略使所提网络能够捕捉图像内部的上下文信息,并增强图像之间的特征关系。此外,设计双特征引导聚合(DFGA),将粗糙的全局语义信息嵌入到更精细的代价体构建中,以进一步增强全局和局部特征的感知。同时,通过设计一种特征度量损失,用于评估变换前后的特征偏差,以减少特征错误匹配对深度估计的影响。实验结果表明,在DTU数据集中,所提网络的完整度和整体度量达到0.264、0.302,在Tanks and temples 2个大场景的重建平均值分别达到64.28、38.03。
