In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PS...In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PSHPPs) owners participate in power market. Objective function is defined as participants’ social welfare achieved from power pool and ancillary markets in yearly horizon. Wind turbines have been modeled by probability-generation tree scenarios based on statistical information. We concentrate on investment profits of WTs numbers and its generation capacity beside to PSHPPs and THUs power plants in power systems due to increase in high flexible tools for Independent system operator into the planning and operation planning time interval. For effectiveness evaluation of proposed model, simulation studies are applied on 14-Bus IEEE test power system.展开更多
This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the...This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the structure of single ended inverter with two switches, and takes IGBTs as power switches. The working frequency of the inverter is set at 20 kHz. The control circuit takes PWM circuit as center, and uses single chip computer to complete the manage functions such as the control of working sequence, setting and changing of the welding parameters, sensing of the welding states and communication with outside computer etc. The dynamic reacting time of the whole power is 1 ms, the range of the output current is 5～250 A, the precision of the output current reaches to 1 A. The power strikes arc by contacting workpiece under 5 A, and have convenient interface with system computer. All above shows this power source is one with high performance.展开更多
核电装备质量文本描述了核电装备在设计、采购、施工和调试阶段出现的质量缺陷等问题。由于不同阶段质量事件的发生频率不同,且同一装备对应不同阶段的质量文本中存在相同的关键词和相似的表述形式,针对类型数量不均衡和语义描述耦合的...核电装备质量文本描述了核电装备在设计、采购、施工和调试阶段出现的质量缺陷等问题。由于不同阶段质量事件的发生频率不同,且同一装备对应不同阶段的质量文本中存在相同的关键词和相似的表述形式,针对类型数量不均衡和语义描述耦合的质量文本分类问题,提出一种融合正则反馈焦点损失函数的改进循环池化网络分类模型。首先,采用BERT(Bidirectional Encoder Representation from Transformers)将核电装备质量文本转化为词向量;然后,提出一个改进的3层循环池化网络的分类模型结构,通过增加中间层并选择合适权重,扩大参数训练的提取空间,提升表征质量缺陷语义特征的能力;接着,提出正则反馈焦点损失函数来训练提出分类模型的参数,通过正则项使损失函数的梯度变化更稳定,根据反馈项对损失函数进行基于真实值和预测值之间误差的迭代调整,解决了不均衡样本在训练过程中梯度偏向不均衡的问题;最后,通过归一化指数函数计算出核电装备质量事件对应的阶段。在某核电公司真实数据集和公共数据集上,与Fast_Text网络相比,所提模型的F1值分别提高了2个百分点和1个百分点,实验结果表明该模型在文本分类任务中具有较高的准确性。展开更多
The passive visual sensing method was successfully applied to monitor the weld pool in TIG welding of aluminium alloy. In order to reduce the disturbance from the arc and acquire clear image, two techniques were used:...The passive visual sensing method was successfully applied to monitor the weld pool in TIG welding of aluminium alloy. In order to reduce the disturbance from the arc and acquire clear image, two techniques were used: one was the own-developed computer-controlled variable polarity power(VPP), the other was the composite filter technology. The VPP source did not have high-frequency electromagnetic interference from arc stabilizer in traditional AC welding power, and its output current wave was controlled by computer, so the imaging current and the imaging time could be adjusted easily. Filter spectral window was identified at 650 nm by analyzing the measured arc light spectral distribution. At the end, the high quality and clear images of welding pool of aluminium alloy were successfully acquired at low imaging current.展开更多
文摘In this paper a new market based analytical model is proposed for optimal placement of Wind Turbines (WTs) in power systems. In addition to wind turbines, thermal units (THUs) and Pumped Storage Hydro Power Plants (PSHPPs) owners participate in power market. Objective function is defined as participants’ social welfare achieved from power pool and ancillary markets in yearly horizon. Wind turbines have been modeled by probability-generation tree scenarios based on statistical information. We concentrate on investment profits of WTs numbers and its generation capacity beside to PSHPPs and THUs power plants in power systems due to increase in high flexible tools for Independent system operator into the planning and operation planning time interval. For effectiveness evaluation of proposed model, simulation studies are applied on 14-Bus IEEE test power system.
文摘This paper analyses the performance request of arc welding power source used in intelligent control of weld pool shape in pulsed GTAW, and develops a sample power source. The main circuit of the power source takes the structure of single ended inverter with two switches, and takes IGBTs as power switches. The working frequency of the inverter is set at 20 kHz. The control circuit takes PWM circuit as center, and uses single chip computer to complete the manage functions such as the control of working sequence, setting and changing of the welding parameters, sensing of the welding states and communication with outside computer etc. The dynamic reacting time of the whole power is 1 ms, the range of the output current is 5～250 A, the precision of the output current reaches to 1 A. The power strikes arc by contacting workpiece under 5 A, and have convenient interface with system computer. All above shows this power source is one with high performance.
文摘核电装备质量文本描述了核电装备在设计、采购、施工和调试阶段出现的质量缺陷等问题。由于不同阶段质量事件的发生频率不同,且同一装备对应不同阶段的质量文本中存在相同的关键词和相似的表述形式,针对类型数量不均衡和语义描述耦合的质量文本分类问题,提出一种融合正则反馈焦点损失函数的改进循环池化网络分类模型。首先,采用BERT(Bidirectional Encoder Representation from Transformers)将核电装备质量文本转化为词向量;然后,提出一个改进的3层循环池化网络的分类模型结构,通过增加中间层并选择合适权重,扩大参数训练的提取空间,提升表征质量缺陷语义特征的能力;接着,提出正则反馈焦点损失函数来训练提出分类模型的参数,通过正则项使损失函数的梯度变化更稳定,根据反馈项对损失函数进行基于真实值和预测值之间误差的迭代调整,解决了不均衡样本在训练过程中梯度偏向不均衡的问题;最后,通过归一化指数函数计算出核电装备质量事件对应的阶段。在某核电公司真实数据集和公共数据集上,与Fast_Text网络相比,所提模型的F1值分别提高了2个百分点和1个百分点,实验结果表明该模型在文本分类任务中具有较高的准确性。
文摘The passive visual sensing method was successfully applied to monitor the weld pool in TIG welding of aluminium alloy. In order to reduce the disturbance from the arc and acquire clear image, two techniques were used: one was the own-developed computer-controlled variable polarity power(VPP), the other was the composite filter technology. The VPP source did not have high-frequency electromagnetic interference from arc stabilizer in traditional AC welding power, and its output current wave was controlled by computer, so the imaging current and the imaging time could be adjusted easily. Filter spectral window was identified at 650 nm by analyzing the measured arc light spectral distribution. At the end, the high quality and clear images of welding pool of aluminium alloy were successfully acquired at low imaging current.
基金the financial supports from the National Science and Technology Major Project,China(No.Y2019-VII-0011-0151)the National Natural Science Foundation of China(No.51771190)。
