Both the real part and imaginary part of complex permittivity approximately have a log-linear frequency dependency at low fre- quencies, especially at ultra-low frequencies under conditions of different moisture conce...Both the real part and imaginary part of complex permittivity approximately have a log-linear frequency dependency at low fre- quencies, especially at ultra-low frequencies under conditions of different moisture concentrations and temperatures, which is recognized as the low frequency dispersion (LFD). In order to explain this dispersion, a new mechanism of dielectric response of LFD of oil-paper insula- tion is proposed. A simplified one-dimensional mathematical model of concentration polarization carrier caused by slow migration is developed and solved, which indicates that ion mobility is closely related to the size of gap and the adsorption capacity of cellulose molecu- lar chains to ions. A stochastic statistical model of the carrier mobility induced LFD is also developed. Moreover, actual tests under 50 °C and 2% moisture content were put forward, as well as simulations with according current waveforms. The simulation results agreed well with the experimental data in that concentration polarization of carriers caused by slow migration is the probable cause of low frequency dispersion of dielectric response for oil-paper insulation diagnosis.展开更多
为响应“双碳”战略目标,阶梯式碳交易、绿证交易与需求响应的交互联动具有重要意义,其交互可减少园区的碳排放以及降低园区的运行成本。首先,构建绿证-阶梯式碳交易的数学计算模型;其次,引入需求响应机制,引导用户用电行为,促进新能源...为响应“双碳”战略目标,阶梯式碳交易、绿证交易与需求响应的交互联动具有重要意义,其交互可减少园区的碳排放以及降低园区的运行成本。首先,构建绿证-阶梯式碳交易的数学计算模型;其次,引入需求响应机制,引导用户用电行为,促进新能源的消纳,降低系统运行成本;然后,将系统运行总成本与总碳排放作为多目标优化调度的目标函数,求解模型获得帕累托解集,采用逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)-灰色关联分析法来获取帕累托解集的理想解;最后,设置多个场景进行对比分析,验证了所提模型的实用性与有效性。展开更多
基金Project supported by National Nature Science Foundation of China （51107105）, Sichuan Science Fund for Young Scholars （2011JQ0009）.
文摘Both the real part and imaginary part of complex permittivity approximately have a log-linear frequency dependency at low fre- quencies, especially at ultra-low frequencies under conditions of different moisture concentrations and temperatures, which is recognized as the low frequency dispersion (LFD). In order to explain this dispersion, a new mechanism of dielectric response of LFD of oil-paper insula- tion is proposed. A simplified one-dimensional mathematical model of concentration polarization carrier caused by slow migration is developed and solved, which indicates that ion mobility is closely related to the size of gap and the adsorption capacity of cellulose molecu- lar chains to ions. A stochastic statistical model of the carrier mobility induced LFD is also developed. Moreover, actual tests under 50 °C and 2% moisture content were put forward, as well as simulations with according current waveforms. The simulation results agreed well with the experimental data in that concentration polarization of carriers caused by slow migration is the probable cause of low frequency dispersion of dielectric response for oil-paper insulation diagnosis.
文摘为响应“双碳”战略目标,阶梯式碳交易、绿证交易与需求响应的交互联动具有重要意义,其交互可减少园区的碳排放以及降低园区的运行成本。首先,构建绿证-阶梯式碳交易的数学计算模型;其次,引入需求响应机制,引导用户用电行为,促进新能源的消纳,降低系统运行成本;然后,将系统运行总成本与总碳排放作为多目标优化调度的目标函数,求解模型获得帕累托解集,采用逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)-灰色关联分析法来获取帕累托解集的理想解;最后,设置多个场景进行对比分析,验证了所提模型的实用性与有效性。
