【正文】 技“十二五”規(guī)劃。 特高壓交流輸電技術(shù)現(xiàn)狀與發(fā)展2004年起，國(guó)家電網(wǎng)公司開(kāi)始醞釀和論證特高壓項(xiàng)目。目前，該工程已經(jīng)安全運(yùn)行近一年，系統(tǒng)運(yùn)行穩(wěn)定，設(shè)備狀態(tài)正常，累計(jì)送電80億千瓦小時(shí)，相當(dāng)于輸送煤炭約350萬(wàn)噸。該工程全長(zhǎng)約640公里，其中設(shè)備投資約占一半，設(shè)備國(guó)產(chǎn)化率達(dá)到90%。計(jì)劃在2020年前后，基本形成覆蓋華北、華中、華東地區(qū)的特高壓電網(wǎng)，實(shí)現(xiàn)“西電東送，南北互供”。 （1）確定了特高壓交流輸電標(biāo)準(zhǔn)電壓。在國(guó)際上首次實(shí)現(xiàn)了特高壓系統(tǒng)電壓優(yōu)化控制。特高壓交流試驗(yàn)示范工程安全穩(wěn)定運(yùn)行四年多。（3）形成了特高壓輸變電設(shè)備設(shè)計(jì)、制造和試驗(yàn)關(guān)鍵技術(shù)，建立了完整的技術(shù)產(chǎn)業(yè)體系。（4）實(shí)現(xiàn)了特高壓工程環(huán)境友好目標(biāo)，特高壓交流試驗(yàn)示范工程電磁環(huán)境實(shí)測(cè)滿足國(guó)家環(huán)保要求。特高壓交流試驗(yàn)示范工程成為世界上電壓等級(jí)最高、輸電能力最強(qiáng)的交流輸電工程。四、特高壓交、直流輸電比較特高壓交流輸電優(yōu)點(diǎn)1）提高傳輸容量和傳輸距離。所需電網(wǎng)電壓等級(jí)越高，緊湊型輸電的效果越好。3）節(jié)省線路走廊和變電站占地面積。kV輸電線路可代替6回500采用特高壓輸電提高了走廊利用率。就我國(guó)而言,％每年就相當(dāng)于新增加500萬(wàn)kW500kV的線損大5倍以上。自19651984年世界上共發(fā)生了6次交流大電網(wǎng)瓦解事故，其中4次發(fā)生在美國(guó)，2次在歐洲。特別是在特高壓線路出現(xiàn)初期，不能形成主網(wǎng)架，線路負(fù)載能力較低，電源的集中送出帶來(lái)了較大的穩(wěn)定性問(wèn)題。另外，特高壓交流輸電對(duì)環(huán)境影響較大。由此可見(jiàn)，在一定輸電電壓下，交流輸電容許輸送功率和距離受到網(wǎng)絡(luò)結(jié)構(gòu)和參數(shù)的限制，還須采取提高穩(wěn)定性的措施，增加了費(fèi)用。因此，直流輸電的輸送容量和距離不受同步運(yùn)行穩(wěn)定性的限制，還可連接兩個(gè)不同頻率的系統(tǒng)，實(shí)現(xiàn)非同期聯(lián)網(wǎng)，提高系統(tǒng)的穩(wěn)定性。如用交流輸電線連接兩個(gè)交流系統(tǒng)，短路容量增大，甚至需要更換斷路器或增設(shè)限流裝置。3）調(diào)節(jié)快速，運(yùn)行可靠。在交直流線路并列運(yùn)行時(shí)，如果交流線路發(fā)生短路，可短暫增大直流輸送功率以減少發(fā)電機(jī)轉(zhuǎn)子加速，提高系統(tǒng)的可靠性。直流線路穩(wěn)態(tài)時(shí)無(wú)電容電流，沿線電壓分布平穩(wěn)，無(wú)空、輕載時(shí)交流長(zhǎng)線受端及中部發(fā)生電壓異常升高的現(xiàn)象，也不需要并聯(lián)電抗補(bǔ)償。按同電壓500m，一條交流線路走廊～50 結(jié)語(yǔ) ａ．２０世紀(jì)９０年代至本世紀(jì)初，特高壓輸電技術(shù)發(fā)展陷入低潮，根本原因是相關(guān)國(guó)家的經(jīng)濟(jì)和用電的增長(zhǎng)速度都比預(yù)期低很多，發(fā)展特高壓大容量輸電的必要性下降。ｂ．中國(guó)特高壓電網(wǎng)將由１０００ｋＶ級(jí)交流輸電系統(tǒng)和177。前者主要定位于近距離大容量輸電和更高一級(jí)電壓等級(jí)的網(wǎng)架建設(shè)；后者主要定位于送受關(guān)系明確的遠(yuǎn)距離大容量輸電以及部分大區(qū)、省網(wǎng)之間的互聯(lián)。ｃ．只要有效控制桿塔的保護(hù)角，特別是轉(zhuǎn)角桿塔的保護(hù)角，特高壓交流輸電線路雷擊跳閘問(wèn)題應(yīng)該是可以解決的。ｄ．特高壓直流系統(tǒng)的系統(tǒng)設(shè)備復(fù)雜，二次設(shè)備故障率高以及換流器在交、直流側(cè)會(huì)產(chǎn)生諧波影響系統(tǒng)的穩(wěn)定控制。ｅ．無(wú)論特高壓交流還是特高壓直流輸電，單回甚至多回線路跳閘，都會(huì)對(duì)受端電網(wǎng)穩(wěn)定產(chǎn)生影響。在特高壓直流輸電方式中，要重視“多饋入直流輸電系統(tǒng)”可能引起系統(tǒng)的安全穩(wěn)定問(wèn)題。ｇ．特高壓直流線路除了特高壓交流線路通常要考慮的電場(chǎng)、磁場(chǎng)、線路可聽(tīng)噪聲、無(wú)線電干擾等對(duì)環(huán)境的影響外，還要進(jìn)一步考慮離子流效應(yīng)、換流站強(qiáng)噪聲對(duì)外界的影響以及換流站接地極對(duì)交流系統(tǒng)的影響?；诜牢坶W的需要，建議中國(guó)特高壓輸電線路優(yōu)先采用大噸位、高強(qiáng)度的合成絕緣子，并采用由數(shù)片玻璃防污絕緣子和合成絕緣子構(gòu)成的組合絕緣子方式，避免合成絕緣子芯棒碳化脆斷事故發(fā)生。參考文獻(xiàn)：特高壓輸電技術(shù)淺析2013年我國(guó)特高壓直流輸電狀況分析淺析我國(guó)高壓直流輸電技術(shù)發(fā)展現(xiàn)狀《科技日?qǐng)?bào)》：特高壓輸電百度百科、百度文庫(kù)等 請(qǐng)您刪除一下內(nèi)容，O(∩_∩)O謝謝?。?！Many people have the same mixed feelings when planning a trip during Golden Week. With heaps of time, the sevenday Chinese請(qǐng)您刪除一下內(nèi)容，O(∩_∩)O謝謝?。?！National Day holiday could be the best occasion to enjoy a destination. However, it can also be the easiest way to ruin how you feel about a place and you may bee more fatigued after the holiday, due to battling the large crowds. During peak season, a dream about a place can turn to nightmare without careful planning, especially if you travel with children and older people. As most Chinese people will take the holiday to visit domestic tourist destinations, crowds and busy traffic are inevitable at most places. Also to be expected are increasing transport and acmodation prices, with the possibility that there will be no rooms available. It is also mon that you39。llNestled close to the country39。You cannot miss out the Autumn of Arxan. It is definitely the best with brightlycolored scenery full of emotions. Shutterbugs flock to see for themselves the marvel of splendid colors around the mountains and waters, many of whom have travel a long distance and even camp here only to capture a moment of the nature wonder. s time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all your fantasies. If its misery, the cow told him to turn its hide into a pair of shoes after it died. The magic shoes whisked Niulang, who carried his two children in baskets strung from a shoulder pole, off on a chase after the empress. The pursuit enraged the empress, who took her hairpin and slashed it across the sky creating the Milky Way which separated husband from wife. But all was not lost as magpies, moved by their love and devotion, formed a bridge across the Milky Way to reunite the family. Even the Jade Emperor was touched, and allowed Niulang and Zhinu to meet once a year on the seventh night of the seventh month. This is how Qixi came to be. The festival can be traced back to the Han Dynasty (206 BCAD 220). Traditionally, people would look up at the sky and find a bright star in the constellation Aquila as well as the star Vega, which are identified as Niulang and Zhinu. The two stars shine on opposite sides of the Milky Way. Customs In bygone days, Qixi was not only a special day for lovers, but also for girls. It is also known as the Begging for Skills Festival or Daughters39。s Day on February 14, characterized by bouquets of roses, chocolates and romantic candlelight dinners, than they do about their homegrown day for lovers. Even Qixi is nowadays referred to as the Chinese Valentine39。s Day! in shops, hotels and restaurants. But few young women will mark the festival with their boyfriends, or take part in traditional activities to pray for cleverness.15