亚洲精品久久久久久一区二区_99re热久久这里只有精品34_久久免费高清视频_一区二区三区不卡在线视频

--- SEARCH ---
WEATHER
CHINA
INTERNATIONAL
BUSINESS
CULTURE
GOVERNMENT
SCI-TECH
ENVIRONMENT
LIFE
PEOPLE
TRAVEL
WEEKLY REVIEW
Learning Chinese
Learn to Cook Chinese Dishes
Exchange Rates
Hotel Service


Hot Links
China Development Gateway
Chinese Embassies

The Ministry of Foreign Affairs
The Ministry of Foreign Trade and Economic Cooperation
Permanent Mission of the People's Republic of China to the UN
Permanent Mission of the People's Republic of China to the United Nations Office at Geneva and other International Organizations in Switzerland
Foreign Affairs College
Institute of American Studies Chinese Academy of Social Sciences
Multiple Causes Lead to Past US Power Emergencies

Numerous factors, both human and nonhuman, have caused emergencies in the US power grid in the past, The Washington Post reported Friday.

Random acts such a hawk landing on a power-line insulator, a raging brush fire beneath a wooden power pole, a failed circuit breaker, lightning, tree limbs, and hot weather trigger dozens of emergencies in the nation's power grid each year, investigative reports by the North American Electric Reliability Council (NERC),the power grid's monitor, were quoted as saying.

Human error, faulty planning and violations of operating rules have also been factors, particularly in a small number of cases in which emergencies cascaded into widespread blackouts.

The same mix of factors is likely to turn up as causes of last week's massive power outage from Michigan to New York, according to officials involved in the Energy Department-led investigation.

"My guess is it's a constellation of things," said one official who would not be identified.

The NERC's annual probes into what it calls "system disturbances" for the past three years and its other reports have carried pointed warnings about "preconditions" -- the existence of weaknesses in parts of the power-transmission networks, particularly in the Midwest where last week's blackout is believed to have started.

The NERC warned two years ago that the rapid increase in long-distance shipments of electricity around the country was straining regional control centers that must respond to emergency disruptions.

In its report, the council expressed concern that generating companies might be cutting back on maintenance or operating safeguards in order to improve profitability, as the industry shifted more power deliveries from regulated sales at fixed rates to unregulated wholesale transactions.

In the 58 power-grid disturbances the council reviewed in 2000, including 35 that caused outages, half involved severe weather and12 involved human error either in maintenance or operations.

The NECR report said as systems are being run "closer to the limit" than ever before, the risk of a disturbance precipitating a cascading outage is great. "Unfortunately, it usually takes a system disturbance to highlight weaknesses in the operation of the electric system."

In its assessment of the outlook for power problems for the summer released in May, the NERC warned of a continuing need for power-system operators in states where last week's blackout erupted to coordinate actions carefully because of the risk of large unanticipated power flows through the area.

Referring to the region monitored by the East Central Area Reliability Council, which includes Michigan and Ohio but not New York, the report said the area's transmission system will be more congested this summer than last and parts of it are vulnerable to large unexpected power flows.
 
(Xinhua News Agency August 23, 2003)

Power Blackouts Hit US, Canadian Cities
Print This Page
|
Email This Page
About Us SiteMap Feedback
Copyright © China Internet Information Center. All Rights Reserved
E-mail: webmaster@china.org.cn Tel: 86-10-68326688
亚洲精品久久久久久一区二区_99re热久久这里只有精品34_久久免费高清视频_一区二区三区不卡在线视频
99国产麻豆精品| 久久人91精品久久久久久不卡 | 日韩一区二区高清| 亚洲丰满少妇videoshd| 黄色亚洲精品| 在线观看av不卡| 在线日韩一区二区| 一区二区三区在线高清| 激情偷拍久久| 尤物在线观看一区| 亚洲国内精品在线| 91久久久精品| 日韩视频中文字幕| 一区二区三区日韩欧美精品| 一区二区三区偷拍| 亚洲一区在线看| 亚洲欧美日韩国产中文在线| 亚洲欧美在线磁力| 欧美在线免费一级片| 欧美在线视频免费| 亚洲激情成人网| 亚洲精品在线二区| 日韩亚洲视频在线| 亚洲一二三区在线| 性做久久久久久免费观看欧美 | 欧美成年网站| 欧美人与性动交α欧美精品济南到| 欧美日韩精品免费观看视频完整 | 国产精品xxxxx| 国产精品综合av一区二区国产馆| 国产精品一区二区男女羞羞无遮挡| 国产欧美日本一区二区三区| 好看的av在线不卡观看| 亚洲国产婷婷香蕉久久久久久99| 亚洲乱码国产乱码精品精天堂| 正在播放欧美视频| 午夜伦欧美伦电影理论片| 欧美影院午夜播放| 亚洲精品日产精品乱码不卡| 一区二区三区国产在线观看| 亚洲欧美在线免费观看| 久久久青草青青国产亚洲免观| 欧美成人精品高清在线播放| 欧美日韩综合在线| 国产午夜精品美女视频明星a级| 在线播放中文字幕一区| 一本色道88久久加勒比精品| 销魂美女一区二区三区视频在线| 亚洲国产精品va在线看黑人 | 久久久国产成人精品| 欧美高清视频一二三区| 欧美视频福利| 国内外成人免费激情在线视频| 亚洲国产一区二区a毛片| 亚洲小说欧美另类婷婷| 亚洲第一黄色| 亚洲香蕉在线观看| 久久在线播放| 欧美偷拍一区二区| 极品尤物一区二区三区| 99精品免费视频| 久久精品国产99精品国产亚洲性色 | 欧美日韩一区二区免费在线观看 | 欧美在线视频一区| 一区二区三区**美女毛片| 久久精品2019中文字幕| 欧美美女bb生活片| 国产一区二区三区成人欧美日韩在线观看| 最新亚洲一区| 欧美在线免费| 亚洲影院在线| 欧美电影在线观看完整版| 国产欧美精品国产国产专区| 亚洲精品三级| 亚洲成在线观看| 欧美一级二级三级蜜桃| 欧美喷水视频| 伊人成人开心激情综合网| 亚洲女人天堂av| 一区二区三区高清在线观看| 久久天天狠狠| 国产欧美一区在线| 一本色道久久加勒比88综合| 亚洲激情欧美激情| 久久精品一区二区三区不卡牛牛 | 一本色道久久88综合亚洲精品ⅰ | 亚洲精品国产精品国产自| 欧美中文字幕视频| 午夜视频一区二区| 欧美日本亚洲| 在线日本高清免费不卡| 亚洲欧美中日韩| 亚洲欧美日韩国产综合| 欧美日韩在线看| 亚洲人成精品久久久久| 亚洲高清不卡一区| 久久久久久久久伊人| 国产精品私拍pans大尺度在线 | 国产精品国产馆在线真实露脸| 亚洲欧洲免费视频| 亚洲国产天堂久久国产91| 久久精品99国产精品日本| 国产精品欧美日韩一区| 夜夜嗨av一区二区三区网页 | 久久免费少妇高潮久久精品99| 国产精品毛片在线| 亚洲天堂av在线免费观看| 亚洲视频一区二区免费在线观看| 欧美极品一区| 亚洲承认在线| 亚洲黄一区二区| 欧美成人免费在线| 在线日韩中文字幕| 亚洲人成毛片在线播放女女| 欧美不卡在线| 亚洲经典自拍| 日韩一二三区视频| 欧美日韩999| 亚洲日本电影| 亚洲桃花岛网站| 国产精品s色| 亚洲午夜一二三区视频| 亚洲欧美日韩精品一区二区| 国产精品久久久久久久浪潮网站 | 欧美成人中文| 亚洲国产专区| 一区二区三区毛片| 欧美午夜剧场| 亚洲你懂的在线视频| 欧美在线一区二区三区| 国产一区二区三区黄| 久久精品国产91精品亚洲| 麻豆91精品| 在线日韩中文字幕| 日韩亚洲精品在线| 欧美色综合天天久久综合精品| 在线综合亚洲欧美在线视频| 午夜精品一区二区三区电影天堂| 国产精品乱码人人做人人爱| 亚洲欧美国产精品va在线观看| 久久精品99国产精品| 精品99一区二区三区| 亚洲精品小视频在线观看| 欧美另类69精品久久久久9999| 一区二区91| 欧美一区高清| 在线欧美电影| 亚洲深夜福利视频| 国产女主播视频一区二区| 欧美中文字幕不卡| 欧美国产日韩在线| 中文精品一区二区三区| 久久精品亚洲精品| ●精品国产综合乱码久久久久| a4yy欧美一区二区三区| 国产精品推荐精品| 91久久国产自产拍夜夜嗨| 欧美日韩一区二| 亚久久调教视频| 欧美激情免费在线| 亚洲天堂av在线免费观看| 久久青青草原一区二区| 亚洲精品国产精品乱码不99| 亚洲欧美日韩综合aⅴ视频| 国语自产精品视频在线看一大j8 | 亚洲宅男天堂在线观看无病毒| 久久久久久久性| 亚洲欧洲日本国产| 小处雏高清一区二区三区| 136国产福利精品导航| 亚洲男同1069视频| 樱桃视频在线观看一区| 亚洲深夜影院| 一区在线观看| 午夜精品www| 亚洲国产日韩美| 欧美一区高清| 日韩视频一区| 欧美好骚综合网| 久久久亚洲午夜电影| 亚洲欧洲精品一区二区三区不卡| 午夜精品久久久久| 亚洲二区在线视频| 欧美一区深夜视频| 亚洲精品美女91| 久久久免费精品| 中文亚洲免费| 欧美高潮视频| 欧美有码在线观看视频| 欧美亚韩一区| 亚洲三级国产| 国产一区二区三区久久悠悠色av| 亚洲私拍自拍| 亚洲黄色有码视频| 久久久久成人精品免费播放动漫| 一区二区三区偷拍| 欧美精品自拍| 亚洲国产欧美另类丝袜| 国产视频一区欧美| 亚洲免费在线视频一区 二区|