【正文】 切斷容量（MVA）RN1101040250200熔斷器的額定電流=250A= 所用變的選擇對于110kV終端變電所，從可靠性角度來說，應(yīng)選擇一臺(tái)所用變。實(shí)際上正常運(yùn)行時(shí)變電所的所用負(fù)荷是很小的，只有十幾千瓦，最大負(fù)荷也只有幾十千瓦。在考慮全站檢修和特殊情況下的用電，選擇所用變的容量為50kVA較好。對于110kV的終端變電站的所用變，接在10kV母線上。[4]10kV所用變的選擇由所用變的容量和所用變壓器的特點(diǎn)選擇S950/10型少油變壓器技術(shù)數(shù)據(jù)見表228所示。S950/10系列610KV級(jí)銅繞組配電變壓器技術(shù)數(shù)據(jù)[8]表228型號(hào)額定電壓（KV）損耗（KW）阻抗電壓（%）空載電流（%）S950/10高壓低壓空載短路4103 設(shè)計(jì)和校驗(yàn)?zāi)妇€系統(tǒng) 110kV側(cè)選擇圓形截面，能有效防止電暈，因?yàn)閳A形母線消除了電場集中的現(xiàn)象,35KV屋外配電裝置、10KV的屋內(nèi)配電裝置，選擇矩形截面母線，其原因是：同樣截面的矩形母線周長比圓形母線的周長要長，散熱面積大，冷卻條件好；其次，由于集膚效應(yīng)的影響，矩形母線的電阻比圓形的小，因而，在同一允許工作電流下，矩形母線截面要比圓形母線的截面積小，用金屬量少[4]。因此，屋內(nèi)配電裝置中采用矩形截面母線比圓形截面母線優(yōu)越。導(dǎo)線的選擇：（1）、選擇母線的形式：由于鋼芯鋁絞線的耐張性能比單股鋁母線好，在允許電流相同時(shí)，其直徑比單股母線直徑大，其表面附近的電場強(qiáng)度小于單股母線，機(jī)械強(qiáng)度較大，集膚效應(yīng)大，可以防止電暈的產(chǎn)生，并且起可以使變電站的屋外配電裝置簡單、投資少、比較經(jīng)濟(jì)，所以可采用鋼芯鋁絞線。（2）、放置形式：水平放置 相間距離： a= l= (3)、 按經(jīng)濟(jì)電流密度法來選擇母線截面積 110kV側(cè)母線選擇（1）、按經(jīng)濟(jì)電流密度選擇母線截面： 式中： 經(jīng)濟(jì)截面 ，：正常工作情況下電路中的最大長期工作電流A J：經(jīng)濟(jì)電流密度 ，A/最大長期工用電流=====(A)因?yàn)樽畲罄眯r(shí)數(shù)：(h/a)4000h/a取J=106A/mm2=== (mm2)查有關(guān)手冊： (mm2)，LGJ185鋼芯鋁絞線 。其技術(shù)數(shù)據(jù)見表229所示。 LGJ185型鋼芯鋁絞線參數(shù)表[1]表229標(biāo)稱截面（mm2）結(jié)構(gòu)尺寸（mm）計(jì)算截面（mm2）計(jì)算外徑（mm）鋁股鋼芯鋁股鋼芯電線鋼芯185287（2）、校驗(yàn)?zāi)妇€的熱穩(wěn)定性：最小允許截面積 =有以上斷路器計(jì)算可得，短路全電流熱效應(yīng)= =(mm2)1280(mm2),所以鋼芯鋁絞線LGJ185滿足熱穩(wěn)定性的要求 35kV側(cè)母線選擇(1)、 ===(A)因?yàn)樽畲罄眯r(shí)數(shù)：(h/a)4000h/a取J=106A/mm2=== (mm2)35kV校驗(yàn)與110kV母線校驗(yàn)相同。查有關(guān)手冊：,其技術(shù)數(shù)據(jù)見表230所示。 LGJ型鋼芯鋁絞線參數(shù)表[1]表230標(biāo)稱截面（mm2）結(jié)構(gòu)尺寸（mm）計(jì)算截面（mm2）計(jì)算外徑（mm）鋁股鋼芯鋁股鋼芯電線鋼芯4002819室溫下母線允許最大電流 =800A實(shí)際環(huán)境溫度為35℃時(shí)母線允許的電流=K=800=校驗(yàn)同110kV側(cè)母線校驗(yàn)相同= ==19所以鋼芯鋁絞線LGJ400滿足熱穩(wěn)定性的要求 10kV母線選擇及校驗(yàn)(1)、 ===(A)因?yàn)樽畲罄眯r(shí)數(shù)：(h/a)3000h/a取J=106A/mm2=== (mm2)查有關(guān)手冊：選擇2(808)(mm2)=1280mm2的鋁母線=1858A溫度修正系數(shù)為：同理：校驗(yàn)與110kV校驗(yàn)相同(2) 有以上斷路器計(jì)算可得，短路全電流熱效應(yīng)= =(mm2)1280(mm2),滿足熱穩(wěn)定性的要求（3）、動(dòng)穩(wěn)定校驗(yàn)(計(jì)算同上),不考慮母線共振。a== ， N/m=106 Pa 68,故滿足動(dòng)穩(wěn)定。參 考 文 獻(xiàn)[1] 馮金光 ， 第三版，221238[2] 孫國凱 霍利民 柴玉華. 電力系統(tǒng)繼電保護(hù)原理. 中國水利水電出版社，1985， [3] 戈東方 ，1989年12月，第一版[4] 丁毓山. ，2000年，第一版，85109[5] 何仰贊. ，1984年，第一版，65135[6] 國家電網(wǎng)公司戰(zhàn)略規(guī)劃部 . ELECTRICITY . 2003年1月第1期，[7] . 中國水利水電出版社，[8] 雄信銀 ，2004年8月， 第三版，107114附 錄英文原文Development and Prospect of China Power Grids Development course of China power gridsChina power networks have been growing with the development of the Chinese power industry. Up to the end of 2002, the total generating capacity of China power systems has GW with yearly generation TWh, the total length of the transmission lines above 220 kV is188,000 km, and the substation capacity is 520,000 MVA. The main 500 kV and330 kV framework have formed in Northeast China, North China, East China, Central China, Northwest China and South China power grids. Among the above grids, even the smallest one has an installed generating capacity over 27,000 MW. And the generating capacity of East China Power Grid has reached 76,000 MW.Decades of years, China power grids experienced a long process of development. However , the real breakthrough happened thirty years ago . The developing process of China power grids could be divided into three stages.The stage of forming local power gridsThis stage continued till the end of1960s and the beginning of the period, 220 kV transmission lines gradually connected the distribution power networks of large and middle cities. The local power grids have formed, which only covered individual provinces and the 220 kV lines were used as the main transmission network backbone.Before 1970, the transmission capacity of each power grid was relatively small. The highest operation voltages of many power grids were only 110 kV except for Northeast China, East China, and BeijingTianjinTangshan power system. Without interconnection, all the power systems could hardly resist faults and accidents happened frequently. Power system reliability and power quality could not be guaranteed.The stage of forming acrossprovincial power systems The period, from 1970 to 1980,was a special developing stage. During this period, the power grid of each province was perfected. At the same time, neighboring provincial power grids started to connect each other.After 1970, as the development going on, many isolated 110 kV and220 kV power grids are connected and formed into 220 kV or 330 kV power grids came into being, long distance transmission lines and relatively larger power supply area made stability problems more significant than ever. Up to 1980, China had suffered from power shortage for nearly 20years. Because the development of power sources couldn39。t keep up with the power demands, most investment had been put to construct power plants, so that the situation that the development of power networks did not match the development of power sources, which was caused by the thought regarding power generation more important than power transmission, weakened the operation security of power systems. In addition, this misunderstanding greatly affected the power system design, layout, capital construction and operation management of this time. As a result, 210accidents related to stability totally occurred in China power systems during 1970~1980, averaging 19accidents per year. At that time, power system security and stability were the main concern in power system operation. To aleviate the crisis, the former Ministry of Electric Power adopted powerful measures. It stressed that leaders of all evels should regard power network management as an important work. The goal of what al leaders were pursuing was not only to achieve better management of a power plant or a utility pany but also to achieve better management of the whole power network. After that, the Operation Guide for Power System Security and Stability was constituted and put into effect on and after September 16, departments concerned enhanced management of power networks. Under the direction of the Operation Guide, power system design, layout, capital construction and o