To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation,and to make up for the deficiencies of traditional characterizers,such as 2-furfural,carbon monoxi...To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation,and to make up for the deficiencies of traditional characterizers,such as 2-furfural,carbon monoxide,and carbon dioxide,a method for the simultaneous determination of methanol,ethanol,n−propanol,and η-butanol in oil with a single injection is established by headspace-gas chromatography-mass spectrometry.The measured results show that the determination limits of the four alcohol characterizers can be controlled to 10μg/kg level.Based on this method,the change patterns of the above four alcohols with thermal aging time and degree of polymerization are obtained through thermal aging experimental research.Ethanol,η-propanol,and η-butanol in oil indicate nearly linear correlations with thermal aging time and degree of polymerization,similar to that of methanol.By analyzing 52 sets of measured data of 500 kV EHV transformers in operation,η-butanol is found to have excellent performance,and a new method to evaluate the aging state of oil-paper insulation employing η-butanol and methanol is proposed along with the aging attention value model.The measured data of 500 kV EHV transformers in operation indicate that the combination of η-butanol and methanol as the preferred characterizers can effectively compensate for the shortcoming of traditional characterizers in the early stages of aging,and the feasibility of the method is verified.Two possible pathways for the generation of η-butanol by cellulose cleavage during the aging of oil-paper are proposed from the chemical structure of cellulose.展开更多
Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power su...Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power supply network based on 500/110 kV direct transformation are proposed.An in-depth analysis of the grid structure and substation design is presented along with an application scenario.An accessibility index based on power flow tracing for network evaluation is also proposed.The index is able to present the inner connectivity and power transferability of a power network.A comprehensive evaluation of traditional short circuit,load flow,N-1,economic calculation,and the accessibility index are conducted on the power grid planning of a high-tech industrial park in Wuhan,China.Finally,electric feasibility and reliability are validated,and accessibility and construction investments compared.展开更多
基金supported by Innovation Foundation of China Electric Power Research Institute(GY83-18-006).
文摘To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation,and to make up for the deficiencies of traditional characterizers,such as 2-furfural,carbon monoxide,and carbon dioxide,a method for the simultaneous determination of methanol,ethanol,n−propanol,and η-butanol in oil with a single injection is established by headspace-gas chromatography-mass spectrometry.The measured results show that the determination limits of the four alcohol characterizers can be controlled to 10μg/kg level.Based on this method,the change patterns of the above four alcohols with thermal aging time and degree of polymerization are obtained through thermal aging experimental research.Ethanol,η-propanol,and η-butanol in oil indicate nearly linear correlations with thermal aging time and degree of polymerization,similar to that of methanol.By analyzing 52 sets of measured data of 500 kV EHV transformers in operation,η-butanol is found to have excellent performance,and a new method to evaluate the aging state of oil-paper insulation employing η-butanol and methanol is proposed along with the aging attention value model.The measured data of 500 kV EHV transformers in operation indicate that the combination of η-butanol and methanol as the preferred characterizers can effectively compensate for the shortcoming of traditional characterizers in the early stages of aging,and the feasibility of the method is verified.Two possible pathways for the generation of η-butanol by cellulose cleavage during the aging of oil-paper are proposed from the chemical structure of cellulose.
基金supported in part by the National Natural Science Foundation of China under Grant 51277082in part by Huang He Ying Cai Funding of Wuhanin part by State Grid Hubei Electric Power Company.
文摘Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power supply network based on 500/110 kV direct transformation are proposed.An in-depth analysis of the grid structure and substation design is presented along with an application scenario.An accessibility index based on power flow tracing for network evaluation is also proposed.The index is able to present the inner connectivity and power transferability of a power network.A comprehensive evaluation of traditional short circuit,load flow,N-1,economic calculation,and the accessibility index are conducted on the power grid planning of a high-tech industrial park in Wuhan,China.Finally,electric feasibility and reliability are validated,and accessibility and construction investments compared.
