技術分享|高海拔地區電氣設備設計注意事項
摘(zhai)要:本文(wen)是針對高海拔地(di)區(qu)空(kong)氣(qi)密(mi)度低、氣(qi)壓低、氣(qi)溫(wen)低的(de)(de)自(zi)然(ran)條件,依據我公(gong)(gong)司(si)在那曲地(di)區(qu)納木措金圓建材有(you)限公(gong)(gong)司(si)年產(chan)60萬噸水泥粉(fen)磨(mo)生產(chan)線項目,所(suo)提出的(de)(de)有(you)關低壓電器在高海拔地(di)區(qu)使用與選型時的(de)(de)選擇建議。
關鍵詞(ci):高(gao)海拔、生(sheng)產線(xian)、選型、建議
引言:
眾所周(zhou)知我(wo)國國土遼闊(kuo),土地(di)(di)(di)資源(yuan)豐(feng)富,而(er)海拔超(chao)過(guo)2000米的(de)(de)(de)地(di)(di)(di)區(qu)大(da)約占了(le)國土總(zong)面(mian)積(ji)的(de)(de)(de)35%。而(er)高海拔地(di)(di)(di)區(qu)目前(qian)有(you)著(zhu)良好的(de)(de)(de)發(fa)展(zhan)前(qian)景(jing),這便需要大(da)量的(de)(de)(de)電(dian)氣(qi)(qi)(qi)設(she)備。由于海拔升高會導致氣(qi)(qi)(qi)壓(ya)(ya)、溫(wen)度(du)等一系(xi)列問(wen)題,使得常規的(de)(de)(de)低(di)(di)壓(ya)(ya)電(dian)氣(qi)(qi)(qi)設(she)備無法滿足現場需求(qiu),所以低(di)(di)壓(ya)(ya)電(dian)氣(qi)(qi)(qi)設(she)備如何在(zai)高海拔地(di)(di)(di)區(qu)安全運行(xing),是特別需要注意(yi)的(de)(de)(de)問(wen)題。本(ben)文(wen)依據我(wo)公(gong)司(si)在(zai)那曲(qu)地(di)(di)(di)區(qu)納(na)木措(cuo)金(jin)圓建材有(you)限(xian)公(gong)司(si)年產(chan)60萬噸水泥(ni)粉磨(mo)生(sheng)產(chan)線項目,經過(guo)反復的(de)(de)(de)測試和總(zong)結,針對(dui)高海拔地(di)(di)(di)區(qu)空(kong)氣(qi)(qi)(qi)密度(du)低(di)(di)、氣(qi)(qi)(qi)壓(ya)(ya)低(di)(di)、氣(qi)(qi)(qi)溫(wen)低(di)(di)的(de)(de)(de)自(zi)然條件,提出了(le)低(di)(di)壓(ya)(ya)電(dian)器在(zai)高海拔地(di)(di)(di)區(qu)使用時的(de)(de)(de)選擇(ze)建議。
1 、高海拔地區的特征:
一般(ban)來說(shuo),對(dui)于低壓(ya)配電系統海拔(ba)在2000m以上,高(gao)壓(ya)配電系統海拔(ba)在1000m以上的地區統稱為(wei)高(gao)海拔(ba)地區。據(ju)測算(suan),我國高(gao)海拔(ba)地區面(mian)積(ji)約占全球(qiu)總面(mian)積(ji)65%。高(gao)海拔(ba)地區具有的自(zi)然氣候條(tiao)件較惡(e)劣(lie),其特征(zheng)為(wei):
(1) 空(kong)氣密度及氣壓較低。
(2) 空(kong)氣(qi)溫(wen)度較低(di),溫(wen)度變化較大。
(3) 空氣(qi)絕對濕(shi)度小。
(4) 太陽輻射強度較高。
(5) 降水量較少。
(6) 大風日多。
(7) 土壤溫度較低,且凍結期長。
因(yin)此高海拔地區的開(kai)關柜(ju)在(zai)設計時,需要考慮以上(shang)種種環境因(yin)素(su)。
2、高海拔(ba)地(di)區(qu)對開關(guan)柜的設計要求:
(1)高(gao)海拔對絕緣耐壓(ya)的影響及(ji)應對方案(an)
常用斷(duan)路(lu)(lu)器(qi)的(de)(de)介(jie)質為(wei)空(kong)(kong)氣(qi)(qi),即我們常說的(de)(de)空(kong)(kong)氣(qi)(qi)斷(duan)路(lu)(lu)器(qi),空(kong)(kong)氣(qi)(qi)的(de)(de)介(jie)質絕(jue)緣(yuan)強度是(shi)隨(sui)著氣(qi)(qi)壓的(de)(de)升(sheng)高(gao)而(er)增(zeng)加,在(zai)空(kong)(kong)氣(qi)(qi)稀薄或(huo)真空(kong)(kong)狀(zhuang)態下又隨(sui)著真空(kong)(kong)度的(de)(de)提高(gao)而(er)增(zeng)加。試驗(yan)表(biao)明,海(hai)拔(ba)(ba)每升(sheng)高(gao)1000 m,平(ping)均氣(qi)(qi)壓則(ze)降(jiang)低(di)(di)7.7~10.5 kPa,外絕(jue)緣(yuan)強度降(jiang)低(di)(di)8%~13%,因此(ci)在(zai)電氣(qi)(qi)間(jian)隙(xi)和爬電距離(li)(li)不(bu)改(gai)變的(de)(de)條件下,產品的(de)(de)額定絕(jue)緣(yuan)電壓和額定工作電壓都要降(jiang)低(di)(di)。例:正(zheng)常家(jia)用普(pu)通微型(xing)斷(duan)路(lu)(lu)器(qi)的(de)(de)絕(jue)緣(yuan)耐(nai)壓等(deng)(deng)級為(wei)400V,我想在(zai)高(gao)海(hai)拔(ba)(ba)地區使(shi)用,由于我不(bu)可能改(gai)變其電氣(qi)(qi)間(jian)隙(xi)和爬電距離(li)(li),所以我只能選用絕(jue)緣(yuan)耐(nai)壓等(deng)(deng)級較高(gao)的(de)(de)微型(xing)斷(duan)路(lu)(lu)器(qi)。
加大電(dian)(dian)氣(qi)距離及(ji)爬電(dian)(dian)距離,根據(ju)國家標準:GB/T 16935.1-1997《低壓(ya)系統內設備絕緣配合》中表A2的海拔修(xiu)正系數表,對所在海拔高度的低壓(ya)柜內電(dian)(dian)氣(qi)間隙(xi)(xi)進行驗證。相(xiang)應的電(dian)(dian)氣(qi)間隙(xi)(xi)和爬電(dian)(dian)距離見下表:
海拔高度(m) | <=2000 | 3000 | 4000 | 5000 |
電氣間隙倍增系數 | 1.0 | 1.14 | 1.29 | 1.48 |
電氣間隙 | 10 | 11.4 | 12.9 | 14.8 |
爬電距離 | 12 | 13.7 | 15.5 | 17.8 |
因(yin)此本項(xiang)目設計、加工時,電(dian)(dian)氣間隙按≥16mm;爬電(dian)(dian)距離按≥20mm設計制作(zuo),并且所有(you)母排套(tao)黃、綠、紅熱縮套(tao)管。
(2)高海(hai)拔對分段能力的影(ying)響
分(fen)斷(duan)(duan)能(neng)力(li)(li)是(shi)指斷(duan)(duan)路(lu)器(qi)開關的(de)(de)一種(zhong)特(te)殊功能(neng)。目(mu)前(qian)有(you)36KA、50KA等(deng)規格,斷(duan)(duan)路(lu)器(qi)的(de)(de)分(fen)斷(duan)(duan)能(neng)力(li)(li)是(shi)指該斷(duan)(duan)路(lu)器(qi)安全切斷(duan)(duan)故障(zhang)電流(liu)(liu)的(de)(de)能(neng)力(li)(li),常規的(de)(de)空氣(qi)斷(duan)(duan)路(lu)器(qi)在(zai)選型(xing)時(shi)(shi)會有(you)不同的(de)(de)分(fen)段(duan)能(neng)力(li)(li)供我(wo)們選擇,例如框(kuang)架(jia)斷(duan)(duan)路(lu)器(qi)在(zai)選型(xing)時(shi)(shi)有(you):N型(xing),S型(xing),H型(xing)等(deng)。但由于海(hai)拔(ba)增(zeng)高,空氣(qi)密度的(de)(de)降低(di)(di),大氣(qi)壓力(li)(li)也隨(sui)之(zhi)降低(di)(di),觸(chu)(chu)(chu)頭材料(liao)的(de)(de)熔點(dian)與沸點(dian)也隨(sui)之(zhi)降低(di)(di),在(zai)電弧電流(liu)(liu)高溫的(de)(de)作用(yong)下,觸(chu)(chu)(chu)頭材料(liao)的(de)(de)升華比(bi)低(di)(di)海(hai)拔(ba)時(shi)(shi)快(kuai),觸(chu)(chu)(chu)頭材料(liao)損失嚴重,因此在(zai)高海(hai)拔(ba)地(di)區,電器(qi)的(de)(de)分(fen)斷(duan)(duan)能(neng)力(li)(li)降低(di)(di)。我(wo)們在(zai)選型(xing)時(shi)(shi)則需要選擇高分(fen)斷(duan)(duan)能(neng)力(li)(li)的(de)(de)斷(duan)(duan)路(lu)器(qi)。對(dui)于接觸(chu)(chu)(chu)器(qi)而言,其分(fen)斷(duan)(duan)能(neng)力(li)(li)由使(shi)用(yong)類(lei)別和額(e)定工作電流(liu)(liu)的(de)(de)倍數(shu)來決定,因此在(zai)高海(hai)拔(ba)地(di)區,接觸(chu)(chu)(chu)器(qi)的(de)(de)工作電流(liu)(liu)降為KiIe,其分(fen)斷(duan)(duan)能(neng)力(li)(li)的(de)(de)降低(di)(di)也應(ying)(ying)為NKiIe(N為相應(ying)(ying)使(shi)用(yong)類(lei)別所要求(qiu)的(de)(de)倍數(shu))。
(3)常用(yong)元器件的降容
現(xian)有(you)一般低壓(ya)(ya)電(dian)(dian)(dian)器(qi)(qi)(qi)產品,使(shi)用(yong)于(yu)(yu)高(gao)(gao)原地(di)區時(shi),其(qi)動、靜觸頭和導電(dian)(dian)(dian)體以(yi)及線圈(quan)等部分的溫(wen)度隨海(hai)拔(ba)高(gao)(gao)度的增(zeng)(zeng)(zeng)加而遞(di)增(zeng)(zeng)(zeng)。其(qi)溫(wen)升(sheng)遞(di)增(zeng)(zeng)(zeng)率為海(hai)拔(ba)每升(sheng)高(gao)(gao)100m,溫(wen)升(sheng)增(zeng)(zeng)(zeng)加0.1-0.5K,但大多(duo)數(shu)產品均小于(yu)(yu)0.4K。而高(gao)(gao)原地(di)區氣溫(wen)隨海(hai)拔(ba)高(gao)(gao)度的增(zeng)(zeng)(zeng)加而降(jiang)(jiang)(jiang)低,其(qi)遞(di)減(jian)率為海(hai)拔(ba)每升(sheng)高(gao)(gao)100m,氣溫(wen)降(jiang)(jiang)(jiang)低足夠補償由海(hai)拔(ba)升(sheng)高(gao)(gao)對(dui)(dui)(dui)電(dian)(dian)(dian)器(qi)(qi)(qi)溫(wen)升(sheng)的影響。因(yin)此,對(dui)(dui)(dui)于(yu)(yu)使(shi)用(yong)說明(ming)書沒(mei)有(you)高(gao)(gao)海(hai)拔(ba)降(jiang)(jiang)(jiang)容說明(ming)的低壓(ya)(ya)電(dian)(dian)(dian)器(qi)(qi)(qi)的額定電(dian)(dian)(dian)流值可以(yi)保持不變,對(dui)(dui)(dui)于(yu)(yu)連續工作的大發(fa)熱量電(dian)(dian)(dian)器(qi)(qi)(qi),可適當降(jiang)(jiang)(jiang)低電(dian)(dian)(dian)源等級使(shi)用(yong)。對(dui)(dui)(dui)于(yu)(yu)在使(shi)用(yong)說明(ming)書中有(you)明(ming)確說明(ming)的,按說明(ming)書降(jiang)(jiang)(jiang)容選用(yong)。
ABB公司(si)所產(chan)空氣斷路器降容說明如下:
海拔高度(m) | <=2000 | 3000 | 4000 | 5000 |
額定工作電壓(V) | 690 | 600 | 500 | 440 |
額定電流(In) | In | 0.98In | 0.93In | 0.9In |
對于變頻(pin)器(qi)類(lei)特殊(shu)產品(pin),像ABB等公司在(zai)說明書(shu)中都(dou)有(you)(you)明確指出:如果(guo)海(hai)拔高度(du)在(zai) 1000 ~ 4000 m (3300 ~ 13123 ft) 之(zhi)間,每升高 100 m (328 ft),電流額定值(zhi)減少 1 %。所以(yi)說當遇到超過海(hai)拔4000m的項(xiang)目時,在(zai)變頻(pin)器(qi)上要做特殊(shu)注意(yi),根據現場(chang)設備類(lei)型(xing)與變頻(pin)器(qi)廠(chang)家(jia)進行溝(gou)通,由(you)變頻(pin)器(qi)廠(chang)家(jia)提(ti)供具體選型(xing)資(zi)料。注:由(you)于大多(duo)數變頻(pin)廠(chang)家(jia)可(ke)能不曾在(zai)該高度(du)做過針對性實驗,故提(ti)供不出具體參(can)數資(zi)料,所以(yi)在(zai)選型(xing)時需格外注意(yi)。本次那曲項(xiang)目由(you)我公司技術(shu)(shu)部,多(duo)次與北京ABB電氣傳(chuan)動系(xi)(xi)統(tong)有(you)(you)限公司技術(shu)(shu)負(fu)責(ze)人(ren)溝(gou)通,針對該項(xiang)目地點的環境、溫度(du)、污穢等級(ji)、等一(yi)系(xi)(xi)列現場(chang)情況共(gong)同探討,制定出一(yi)個合理的方案。
對于軟啟(qi)(qi)動(dong)器的(de)降(jiang)(jiang)(jiang)容來說,因(yin)為軟啟(qi)(qi)的(de)工作特(te)性(xing),使得(de)它的(de)降(jiang)(jiang)(jiang)容曲線相較(jiao)變頻來說較(jiao)為平緩,ABB的(de)說明書中當海(hai)拔(ba)高(gao)度(du)在1000米(mi)至4000米(mi)之間時,需要按(an)照(zhao)下(xia)述計算公式降(jiang)(jiang)(jiang)容使用:占Ie的(de)百分比=100- (x-1000)/100 ,x=軟啟(qi)(qi)動(dong)器的(de)實際海(hai)拔(ba)高(gao)度(du)。在我們的(de)咨詢過程中西門子(zi)的(de)軟啟(qi)(qi)動(dong)器官方(fang)給定的(de)最(zui)大安(an)裝高(gao)度(du)為5000m。其(qi)中降(jiang)(jiang)(jiang)容曲線如下(xia)所(suo)示:
(5)電容(rong)器件的選型使用
眾所周知,電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器是(shi)由(you)正(zheng)(zheng)極、負(fu)極和電(dian)(dian)(dian)(dian)解質組成,當(dang)(dang)正(zheng)(zheng)負(fu)極直接(jie)加上一(yi)個(ge)電(dian)(dian)(dian)(dian)壓時(shi)電(dian)(dian)(dian)(dian)極即可儲存電(dian)(dian)(dian)(dian)荷(he),兩(liang)板分別(bie)帶等量(liang)異種電(dian)(dian)(dian)(dian)荷(he),每個(ge)極板帶電(dian)(dian)(dian)(dian)量(liang)的(de)(de)(de)絕對值叫(jiao)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器的(de)(de)(de)帶電(dian)(dian)(dian)(dian)量(liang)。當(dang)(dang)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器兩(liang)極正(zheng)(zheng)負(fu)電(dian)(dian)(dian)(dian)荷(he)通過導線(xian)(xian)中(zhong)和。在(zai)放(fang)電(dian)(dian)(dian)(dian)過程中(zhong)導線(xian)(xian)上有短暫(zan)的(de)(de)(de)電(dian)(dian)(dian)(dian)流產生。這(zhe)就(jiu)是(shi)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器正(zheng)(zheng)常的(de)(de)(de)工作(zuo)示(shi)意,即充電(dian)(dian)(dian)(dian)和放(fang)電(dian)(dian)(dian)(dian),起(qi)到(dao)一(yi)個(ge)儲能(neng)(neng)元件的(de)(de)(de)作(zuo)用(yong)。電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)在(zai)實(shi)際(ji)使(shi)(shi)(shi)用(yong)中(zhong)起(qi)到(dao)調節電(dian)(dian)(dian)(dian)網(wang)質量(liang)的(de)(de)(de)作(zuo)用(yong)。在(zai)那曲(qu)項目剛啟動時(shi),關于電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器,我(wo)們咨(zi)詢(xun)了很多廠家,因為自愈式并聯(lian)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器在(zai)制作(zuo)工藝上的(de)(de)(de)問題,且受困于材料本身的(de)(de)(de)影響,要想將常規電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器使(shi)(shi)(shi)用(yong)在(zai)高海拔(ba)地區它(ta)的(de)(de)(de)絕緣(yuan)強(qiang)度和電(dian)(dian)(dian)(dian)氣(qi)間隙不能(neng)(neng)滿足(zu)實(shi)際(ji)需求。經(jing)過我(wo)們不斷與電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)廠家相互(hu)探討,電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)廠家為我(wo)們特(te)制一(yi)款高原型的(de)(de)(de)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器,該(gai)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器采用(yong)拉(la)大電(dian)(dian)(dian)(dian)氣(qi)間隙和更換絕緣(yuan)介質的(de)(de)(de)方法,來增加電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器的(de)(de)(de)絕緣(yuan)強(qiang)度和電(dian)(dian)(dian)(dian)氣(qi)間隙,使(shi)(shi)(shi)的(de)(de)(de)該(gai)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)器可以(yi)在(zai)海拔(ba)4600米上的(de)(de)(de)工程流水(shui)線(xian)(xian)上正(zheng)(zheng)常工作(zuo)。
(6)高海拔對普通二次元(yuan)器件的影響
高海拔(ba)對低壓(ya)二次元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)的(de)影響,主要方面也(ye)是電氣間隙和元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)本身材料上(shang),因(yin)為高海拔(ba)地區(qu)平(ping)均(jun)氣溫較(jiao)低,冬天的(de)時候平(ping)均(jun)氣溫會(hui)低于部分元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)的(de)貯藏溫度(du),因(yin)此(ci)可能會(hui)導(dao)致元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)還未經(jing)使用(yong),就(jiu)已(yi)出現(xian)(xian)損壞(huai)現(xian)(xian)象(xiang),這些在(zai)互感器(qi)(qi)(qi)、多功能表(biao)、指示燈等(deng)元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)上(shang)表(biao)現(xian)(xian)的(de)較(jiao)為明顯,故而(er)該類產品在(zai)使用(yong)時需要特(te)殊處(chu)理,以(yi)增加元(yuan)器(qi)(qi)(qi)件(jian)(jian)(jian)(jian)的(de)耐腐蝕度(du)。
(7)高海拔對柜體的(de)影響(xiang)
該項目我們選用的是ABB 的MNS2.0低壓抽出式開(kai)關柜,但(dan)是在傳統(tong)的(de)開(kai)關柜上我(wo)們做(zuo)了(le)更加詳細特(te)殊的(de)絕緣處理。
a):在(zai)封閉式垂直母線通道上(shang),我們將垂直排與柜體(ti)之間的間隙加大(da),以保證母排與殼體(ti)的最(zui)小間隙大(da)于安全間隙;
b):抽屜柜的安全位置是由(you)一個(ge)微斷開關(guan)在把手(shou)的作用下調節至我們所需(xu)要的點位,但由(you)于(yu)抽屜實驗(yan)位置的插件(jian)間隙較小(xiao),所以我們想方法在插件(jian)的線頭上套一個(ge)透明(ming)的保(bao)護套,以此來增加他(ta)的絕緣強(qiang)度;
c):在所(suo)有的(de)元器(qi)件(jian)與固(gu)定板(ban)之間(jian)增加一塊絕緣板(ban),以(yi)此增加相間(jian)對地的(de)保(bao)護,例(li)如在熔斷器(qi)后增加一塊絕緣板(ban),使得熔斷器(qi)的(de)螺絲與安裝板(ban)隔開;
d):當潤(run)滑油進(jin)入低溫(wen)后(hou),蠟(la)質結(jie)晶(jing)會析出(chu)、結(jie)晶(jing)從而(er)導致粘度增大,溫(wen)度升高(gao)后(hou)蠟(la)質結(jie)晶(jing)受到破壞,回(hui)復原始粘度,從而(er)失去潤(run)滑的效果。因此本項目我(wo)們采用特制(zhi)潤(run)滑油,該(gai)潤(run)滑油可(ke)(ke)以(yi)保證在低溫(wen)下可(ke)(ke)以(yi)正常(chang)使用,不會出(chu)現(xian)粘度會變大等(deng)現(xian)象(xiang);
e):正(zheng)常抽屜柜所使用(yong)的(de)二次(ci)插(cha)件(jian)之(zhi)間的(de)距離不能滿(man)足現場(chang)需求, 對此我們采用(yong)了(le)用(yong)一拆一的(de)方法,每相鄰兩個(ge)插(cha)件(jian)中間隔(ge)開一個(ge)空格(ge)插(cha)件(jian),拆除該插(cha)件(jian)上的(de)金屬(shu)片(pian),以此增加插(cha)件(jian)之(zhi)間的(de)電氣間隙。
3、結束語
目(mu)前(qian),我國在高(gao)(gao)(gao)(gao)海(hai)拔地(di)區(qu)(qu)的(de)(de)發(fa)(fa)展還(huan)處于起步階(jie)段(duan),現(xian)階(jie)段(duan)關于高(gao)(gao)(gao)(gao)低壓電(dian)(dian)(dian)氣(qi)如何在高(gao)(gao)(gao)(gao)海(hai)拔地(di)區(qu)(qu)應(ying)用(yong)(yong)還(huan)需要做(zuo)更多的(de)(de)驗證和(he)實(shi)(shi)踐,而低壓電(dian)(dian)(dian)氣(qi)應(ying)用(yong)(yong)于高(gao)(gao)(gao)(gao)海(hai)拔地(di)區(qu)(qu)勢(shi)在必行(xing)。此(ci)次,我公(gong)司的(de)(de)經典案例,為低壓電(dian)(dian)(dian)氣(qi)在高(gao)(gao)(gao)(gao)海(hai)拔地(di)區(qu)(qu)的(de)(de)應(ying)用(yong)(yong)提供有利的(de)(de)經驗和(he)保(bao)證,為我公(gong)司在高(gao)(gao)(gao)(gao)海(hai)拔領(ling)域的(de)(de)發(fa)(fa)展打下堅實(shi)(shi)的(de)(de)基礎。
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