Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 y...Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 years. Prom the distribution of the linear trend, it can be concluded that the southeastern part of T-P becomes warmer and wetter, with an obvious increase of rainfall. The same characteristics are found in the southwestern part of T-P, but the shift is smaller. In the middle of T-P, temperature and humidity obviously increase with the center of the increase in Bangoin-Amdo. The south of the Tarim Basin also exhibits the same tendency. The reason for this area being humid is that it gets less sunshine and milder wind. The northeastern part of T-P turns warmer and drier. Qaidam Basin and its western and southern areas are the center of this shift, in which the living environment is deteriorating. Analyzing the characteristics of the regional average time series, it can be found that in the mid-1970s, a significant sudden change occurred to annual rainfall, yearly average snow-accumulation days and surface pressure in the eastern part of T-P. In the mid-1980s, another evident climatic jump happened to yearly average temperature, total cloud amount, surface pressure, relative humidity, and sunshine duration in the same area. That is, in the mid 1980s, the plateau experienced a climatic jump that is featured by the increase of temperature, snow-accumulation days, relative humidity, surface pressure, and by the decrease of sunshine duration and total cloud amount. The sudden climatic change of temperature in T-P is later than that of the global-mean temperature. Prom this paper it can be seen that in the middle of the 1980s, a climatic jump from warm-dry to warm-wet occurred in T-P.展开更多
近年来,高比例可再生能源发电接入我国电网,通过多条特高压/超高压交直流输电线路实现远距离传输,电网对故障后的暂态电压过程更加敏感,暂态电压安全成为我国电网的核心威胁之一。这已经成为国内外学术界和产业界关注的热点,其中一个焦...近年来,高比例可再生能源发电接入我国电网,通过多条特高压/超高压交直流输电线路实现远距离传输,电网对故障后的暂态电压过程更加敏感,暂态电压安全成为我国电网的核心威胁之一。这已经成为国内外学术界和产业界关注的热点,其中一个焦点是如何通过有效的控制手段降低出现暂态电压不安全的风险。该文设计并研发了面向高比例可再生能源交直流混联电网的动态自动电压控制(dynamic automatic voltage control,DAVC)系统,通过考虑在线预想故障集的预防控制,提升电网故障后的暂态电压支撑能力。阐述了所研制的DAVC系统总体结构、主要功能和系统设计,通过在实际大型电网的应用案例说明其效果。目前,该DAVC系统已经在我国多个网省级电网调度控制中心取得实际在线应用。展开更多
文摘Through analyzing the yearly average data obtained from 123 regular meteorological observatories located in the Tibetan Plateau (T-P), this article studies the characteristics of climate change in T-P in the last 40 years. Prom the distribution of the linear trend, it can be concluded that the southeastern part of T-P becomes warmer and wetter, with an obvious increase of rainfall. The same characteristics are found in the southwestern part of T-P, but the shift is smaller. In the middle of T-P, temperature and humidity obviously increase with the center of the increase in Bangoin-Amdo. The south of the Tarim Basin also exhibits the same tendency. The reason for this area being humid is that it gets less sunshine and milder wind. The northeastern part of T-P turns warmer and drier. Qaidam Basin and its western and southern areas are the center of this shift, in which the living environment is deteriorating. Analyzing the characteristics of the regional average time series, it can be found that in the mid-1970s, a significant sudden change occurred to annual rainfall, yearly average snow-accumulation days and surface pressure in the eastern part of T-P. In the mid-1980s, another evident climatic jump happened to yearly average temperature, total cloud amount, surface pressure, relative humidity, and sunshine duration in the same area. That is, in the mid 1980s, the plateau experienced a climatic jump that is featured by the increase of temperature, snow-accumulation days, relative humidity, surface pressure, and by the decrease of sunshine duration and total cloud amount. The sudden climatic change of temperature in T-P is later than that of the global-mean temperature. Prom this paper it can be seen that in the middle of the 1980s, a climatic jump from warm-dry to warm-wet occurred in T-P.
文摘近年来,高比例可再生能源发电接入我国电网,通过多条特高压/超高压交直流输电线路实现远距离传输,电网对故障后的暂态电压过程更加敏感,暂态电压安全成为我国电网的核心威胁之一。这已经成为国内外学术界和产业界关注的热点,其中一个焦点是如何通过有效的控制手段降低出现暂态电压不安全的风险。该文设计并研发了面向高比例可再生能源交直流混联电网的动态自动电压控制(dynamic automatic voltage control,DAVC)系统,通过考虑在线预想故障集的预防控制,提升电网故障后的暂态电压支撑能力。阐述了所研制的DAVC系统总体结构、主要功能和系统设计,通过在实际大型电网的应用案例说明其效果。目前,该DAVC系统已经在我国多个网省级电网调度控制中心取得实际在线应用。
