電能表定義
專門用來計量某一時間段電能累計值的儀表叫做電能表,俗稱電度(du)表、火表、千瓦小時表。
電能(neng)表是(shi)采樣技(ji)(ji)術(shu)、微處理技(ji)(ji)術(shu)、設計(ji)技(ji)(ji)術(shu)和經驗相結合的(de)(de)(de)產物,是(shi)跨學科的(de)(de)(de)高技(ji)(ji)術(shu)產品。電能(neng)表制(zhi)造商(shang)根據自身設計(ji)的(de)(de)(de)理解和應用技(ji)(ji)巧,實現電能(neng)表的(de)(de)(de)各項功能(neng)。電能(neng)表產品上(shang),目前(qian)(qian)已經具備了多功能(neng)、網(wang)絡(luo)化、智能(neng)化、數(shu)字(zi)化的(de)(de)(de)需求(qiu),能(neng)夠(gou)滿足(zu)當前(qian)(qian)各種(zhong)計(ji)量的(de)(de)(de)要求(qiu),如有(you)功計(ji)量、無功計(ji)量、需量計(ji)算,電網(wang)質量檢測、電網(wang)事件記錄等(deng)復雜功能(neng),并能(neng)夠(gou)作為通訊從站(zhan)與中央控制(zhi)主站(zhan)進行數(shu)據交互。
電能表分類
1、按用途:有(you)功(gong)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)、無(wu)功(gong)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)、最大需量表(biao)、標準電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)、復費率(lv)分時電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)、預付費電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)(分投幣(bi)式、磁卡式、電(dian)(dian)(dian)(dian)(dian)卡式)、損耗電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)、多功(gong)能(neng)(neng)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)和智(zhi)能(neng)(neng)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)表(biao)。
2、按工作(zuo)原理:感應(ying)式(機械式)、靜止式(電子式)、機電一體式(混合式)。
3、按接入電源性質:交流表、直流表。
4、按結構:整體式(shi)、分體式(shi)。
5、按接入相(xiang)線:單相(xiang)、三(san)(san)相(xiang)三(san)(san)線、三(san)(san)相(xiang)四線電能表。
6、按準確級:普通安裝式電能表(0.2S、0.5S、0.2.0.5.1.0、2.0級)和攜帶(dai)式精密電能表(0.01、0.05、0.2級(ji))。
7、按安裝接(jie)線方式:直接(jie)接(jie)入式、間接(jie)接(jie)入式。
電能表型號
目前,電(dian)能表的形式(shi)及(ji)功(gong)能是多種多樣的,各電(dian)能表品牌(pai)廠家在型(xing)號命(ming)名上也(ye)不盡完全相同,普通有(you)功(gong)電(dian)能表只用兩個字(zi)母(mu)表示其功(gong)能和(he)用途。有(you)特殊功(gong)能或電(dian)子式(shi)的電(dian)能表多用三個字(zi)母(mu)表示其功(gong)能和(he)用途。舉例(li)如下。
1、DD28表(biao)(biao)示(shi)單相電能表(biao)(biao)。第一個(ge)字(zi)母D表(biao)(biao)示(shi)電能表(biao)(biao),第二個(ge)字(zi)母D表(biao)(biao)示(shi)單相,9Q為設計(ji)序號。
2、DS862表(biao)示三相三線有功電(dian)能表(biao)。第(di)一(yi)個字母(mu)(mu)D表(biao)示電(dian)能表(biao),第(di)二個字母(mu)(mu)S表(biao)示三相三線,86為設計序(xu)(xu)號,2為改進序(xu)(xu)號。
3、DT862表(biao)(biao)示三(san)相四線有功電(dian)能表(biao)(biao)。D表(biao)(biao)示電(dian)能表(biao)(biao),T表(biao)(biao)示三(san)相四線,86為設(she)計序號(hao),2表(biao)(biao)示改進序號(hao)。
4、叨表示(shi)直流(liu)電(dian)(dian)能表。D表示(shi)電(dian)(dian)能表,J表示(shi)直流(liu)。
5、DB表(biao)示(shi)標(biao)準電能(neng)表(biao)。D表(biao)示(shi)電能(neng)表(biao),B表(biao)示(shi)標(biao)準。
6、DZ表示(shi)(shi)最大(da)需量電(dian)(dian)能(neng)表。D表示(shi)(shi)電(dian)(dian)能(neng)表,z表示(shi)(shi)最大(da)需量。
7、¤禿表示三(san)相(xiang)三(san)線標準電能表。D表示電能表,B表示標準,S表示三(san)相(xiang)三(san)線。
8、DBT表(biao)(biao)示三相四(si)線(xian)標準電能表(biao)(biao)。D表(biao)(biao)示電能表(biao)(biao),B表(biao)(biao)示標準,T表(biao)(biao)示三相四(si)線(xian)。
9、DX8表(biao)(biao)示(shi)無(wu)功電能表(biao)(biao)。D表(biao)(biao)示(shi)電能表(biao)(biao),X表(biao)(biao)示(shi)無(wu)功,8為(wei)設(she)計(ji)序(xu)號。
10、DTM31表(biao)示(shi)三相四線(xian)脈沖(chong)電(dian)(dian)(dian)能表(biao),D表(biao)示(shi)電(dian)(dian)(dian)能表(biao),T表(biao)示(shi)三相四線(xian),M表(biao)示(shi)脈沖(chong),31為(wei)設(she)計序號(hao)。設(she)計序號(hao)為(wei)33的電(dian)(dian)(dian)能表(biao)是具有(you)同樣功(gong)能的無功(gong)電(dian)(dian)(dian)能表(biao)。該電(dian)(dian)(dian)能表(biao)可用于(yu)工礦企業(ye)及各類營業(ye)單位(wei)計量有(you)功(gong)電(dian)(dian)(dian)能或無功(gong)電(dian)(dian)(dian)能。可以遠距(ju)離采集脈沖(chong)信號(hao),編程控制(zhi)調控電(dian)(dian)(dian)能,節省人力,提高工作(zuo)效率。
11、DTD18表示三相四線有功多功能電能表。D表示電能表,T表示三相四線,D表示多功能,18為設計序號。該表除具有一般計量功能外,還有峰谷、平時分段電能計量及最大需量顯示、需量累計等40多種功能,是工礦企業等用電部門實行多費率、分時計價、合理用電的計量儀表。
電能表原理
當把電(dian)(dian)能(neng)表(biao)接(jie)入被測電(dian)(dian)路(lu)時(shi),電(dian)(dian)流(liu)線(xian)圈(quan)和(he)電(dian)(dian)壓線(xian)圈(quan)中(zhong)(zhong)就(jiu)有(you)交變(bian)(bian)電(dian)(dian)流(liu)流(liu)過(guo)(guo),這兩個(ge)交變(bian)(bian)電(dian)(dian)流(liu)分別在它們的(de)(de)(de)(de)(de)(de)鐵芯中(zhong)(zhong)產生交變(bian)(bian)的(de)(de)(de)(de)(de)(de)磁(ci)(ci)通;交變(bian)(bian)磁(ci)(ci)通穿過(guo)(guo)鋁(lv)(lv)(lv)(lv)盤(pan),在鋁(lv)(lv)(lv)(lv)盤(pan)中(zhong)(zhong)感應出渦流(liu);渦流(liu)又(you)在磁(ci)(ci)場中(zhong)(zhong)受到(dao)力(li)(li)(li)的(de)(de)(de)(de)(de)(de)作用(yong),從而使鋁(lv)(lv)(lv)(lv)盤(pan)得到(dao)轉(zhuan)(zhuan)(zhuan)矩(ju)(ju)(ju)(ju)(ju)(主動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju))而轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)。負(fu)載消耗(hao)的(de)(de)(de)(de)(de)(de)功率越(yue)(yue)大(da),通過(guo)(guo)電(dian)(dian)流(liu)線(xian)圈(quan)的(de)(de)(de)(de)(de)(de)電(dian)(dian)流(liu)越(yue)(yue)大(da),鋁(lv)(lv)(lv)(lv)盤(pan)中(zhong)(zhong)感應出的(de)(de)(de)(de)(de)(de)渦流(liu)也(ye)越(yue)(yue)大(da),使鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)就(jiu)越(yue)(yue)大(da)。即轉(zhuan)(zhuan)(zhuan)矩(ju)(ju)(ju)(ju)(ju)的(de)(de)(de)(de)(de)(de)大(da)小跟負(fu)載消耗(hao)的(de)(de)(de)(de)(de)(de)功率成正比。功率越(yue)(yue)大(da),轉(zhuan)(zhuan)(zhuan)矩(ju)(ju)(ju)(ju)(ju)也(ye)越(yue)(yue)大(da),鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)也(ye)就(jiu)越(yue)(yue)快。鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)時(shi),又(you)受到(dao)永久磁(ci)(ci)鐵產生的(de)(de)(de)(de)(de)(de)制動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)的(de)(de)(de)(de)(de)(de)作用(yong),制動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)與(yu)(yu)主動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)方向(xiang)相反;制動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)的(de)(de)(de)(de)(de)(de)大(da)小與(yu)(yu)鋁(lv)(lv)(lv)(lv)盤(pan)的(de)(de)(de)(de)(de)(de)轉(zhuan)(zhuan)(zhuan)速(su)成正比,鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)得越(yue)(yue)快,制動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)也(ye)越(yue)(yue)大(da)。當主動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)與(yu)(yu)制動(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)(ju)(ju)(ju)達到(dao)暫(zan)時(shi)平衡時(shi),鋁(lv)(lv)(lv)(lv)盤(pan)將勻(yun)速(su)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)。負(fu)載所消耗(hao)的(de)(de)(de)(de)(de)(de)電(dian)(dian)能(neng)與(yu)(yu)鋁(lv)(lv)(lv)(lv)盤(pan)的(de)(de)(de)(de)(de)(de)轉(zhuan)(zhuan)(zhuan)數(shu)成正比。鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)時(shi),帶動(dong)(dong)(dong)(dong)(dong)(dong)計數(shu)器(qi),把所消耗(hao)的(de)(de)(de)(de)(de)(de)電(dian)(dian)能(neng)指示(shi)出來。這就(jiu)是(shi)電(dian)(dian)能(neng)表(biao)工作的(de)(de)(de)(de)(de)(de)簡單過(guo)(guo)程。
電能表接線圖
三相電(dian)能(neng)表接(jie)線圖
電能的計量
電能計量單位
有功電能表kW·h(俗(su)稱度1kw。h=3.6×10的(de)6次(ci)方在數值上(shang)表示功率1kw的用(yong)電器工作(zuo)1h所(suo)消(xiao)耗的(de)電能)
無功電能表kvar·h
字輪計度器窗口(液晶顯示窗口):
整數位(wei)(wei)(wei)和小(xiao)數位(wei)(wei)(wei)不同顏色,中間(jian)小(xiao)數點;各字輪(lun)有倍乘(cheng)系(xi)數(無小(xiao)數點時)多功能(neng)表液晶(jing)顯(xian)示(shi)有整數位(wei)(wei)(wei)和小(xiao)數位(wei)(wei)(wei)兩位(wei)(wei)(wei)。
準確度等級:
相對誤(wu)差,用(yong)置于(yu)圓圈內的數字(zi)表示
標定(ding)電流和額定(ding)最大電流:
標定電流:標明于表上作為計算負載的基數電流值:I b
額定最大電流:電能表能長期正常工作,誤差和溫升完全滿足要求的最大電流值:Imax
額定電壓:單相電能表標注:220V
三相表有三種標注法:
A、直接接入式三(san)相三(san)線:3×380V
B、直接接入式三相四線:3×380/220V
電能表常數:電能表記錄的電能與轉盤轉數或脈沖數之間關系的比例數:r/kWh;imp/kWh
電度表使用時應注意哪些事項
1、電(dian)度表(biao)接(jie)線較復(fu)雜,接(jie)線前必須分清電(dian)度表(biao)的電(dian)壓端子(zi)(zi)和電(dian)流(liu)端子(zi)(zi),然后(hou)按(an)照(zhao)說(shuo)明書對號接(jie)入。
2、電度表只(zhi)有在(zai)額定(ding)電壓、額定(ding)電流20~120%額定(ding)頻(pin)率50赫(he)茲的(de)條件下(xia)工(gong)作,才能保證(zheng)準確度。
3、電(dian)度表不宜在小于(yu)規(gui)定(ding)電(dian)流的5%和大約(yue)定(ding)電(dian)流的150%情(qing)況下工作。
4、停用半年的電度表應(ying)重新(xin)校準
5、電度表安(an)裝(zhuang)時,要距(ju)熱力(li)系統0.5米以上,距(ju)地(di)面(mian)0.7~2.0米,并且(qie)要力(li)求垂直安(an)裝(zhuang)。
電表有哪些常見的故障
1、膠木接線盒內出現燒焦糊味
原因一:是在安裝或更換電路導線時,盒內的固定螺絲未擰緊,當電器用電負荷增大時,螺絲柱因接觸不良發熱,燒壞膠木盒并伴發焦糊味。
解決的方法:取(qu)下肢(zhi)術接(jie)線(xian)蓋后拉下總閘刀(dao),將電源導線(xian)全部拆下,重新用刀(dao)將線(xian)頭殘留物刮(gua)干凈(jing),裝入接(jie)線(xian)柱(zhu)內,擰緊全部螺絲即可以排(pai)除(chu)故障。
原因二:從室內接到電表上的導線質量差,引起銅柱與導線間產生氧化層(特別是安裝在環境潮濕,不通風處的電度表容易產生此類問題),從而增大電阻值使接觸點發熱而損壞接線盒。
解決方法:應徹底清除接(jie)線盒內(nei)的油污及更換(huan)導線。有(you)時(shi)當用(yong)電(dian)(dian)設備(bei)超過電(dian)(dian)表(biao)實際安培值時(shi),不僅(jin)接(jie)線盒會(hui)損壞(huai),電(dian)(dian)表(biao)也(ye)有(you)可能被強電(dian)(dian)流擊毀(hui),所(suo)(suo)以當發現(xian)表(biao)的額定(ding)電(dian)(dian)流與實際所(suo)(suo)用(yong)電(dian)(dian)器的總負(fu)荷(he)相差(cha)很大時(shi),應錯開使用(yong)時(shi)間(jian)或更換(huan)電(dian)(dian)度表(biao),以防電(dian)(dian)表(biao)被擊毀(hui)或發生電(dian)(dian)氣火(huo)災。
2、鋁盤停轉或不跳字
電度表是(shi)一種(zhong)精(jing)密計量儀表,它在出廠(chang)前(qian)都是(shi)經(jing)過嚴(yan)格校驗的,其靈(ling)敏度和可(ke)靠性、穩(wen)定性應達到(dao)一定的標準。當負(fu)荷(he)電流小于0.025A時(shi)(shi)(shi),電表鋁盤不轉動、不跳字(zi)屬正常范圍(wei),如果在較大負(fu)荷(he)時(shi)(shi)(shi)仍不轉動,很(hen)可(ke)能是(shi)鋁盤被卡住,鋁盤已(yi)變形或電磁機構失靈(ling)等(deng)問題,應及時(shi)(shi)(shi)送檢。
3、空載時自行轉動
電表在空載時會自行轉動,即住宅內的所有用電設備及照明燈具都未使用,而表的鋁盤仍在轉動或慢慢爬行。一般(ban)來(lai)說(shuo)(shuo),當電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)為額定值的80%至(zhi)110%時,電(dian)(dian)表(biao)鋁盤(pan)的轉動不會超過一圈屬于正常范圍(即轉盤(pan)順時針方向轉動一圈),但若鋁盤(pan)微微轉動不止,則說(shuo)(shuo)明電(dian)(dian)表(biao)線路有漏電(dian)(dian)存在,應請(qing)電(dian)(dian)工檢查處理。如果沒有(you)漏電(dian)(dian)存(cun)在(zai),那就(jiu)是(shi)電(dian)(dian)表自身的故障,應及時(shi)送電(dian)(dian)力部門檢修或(huo)換新表。
4、運行時產生“吱吱”響聲
電(dian)(dian)度表(biao)在(zai)運行時,有輕微的“嗡(weng)嗡(weng)”聲(sheng),屬(shu)于正常現(xian)象(xiang)。但如果表(biao)內(nei)產(chan)生(sheng)不規(gui)則(ze)的雜亂響(xiang)聲(sheng),則(ze)是表(biao)內(nei)部(bu)的某些配件老化、電(dian)(dian)磁場部(bu)分元件松動(dong),或轉動(dong)齒輪缺油等原因所(suo)引起。應送電(dian)(dian)力部(bu)門校驗并更換易損配件。有時,當電(dian)(dian)表(biao)處于嚴重超負荷(he)運行時,也會產(chan)生(sheng)不規(gui)則(ze)的響(xiang)聲(sheng),應及(ji)時關閉部(bu)分電(dian)(dian)器,以防損壞電(dian)(dian)表(biao)。