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,俗稱電度表、火表、千瓦小時表。
電能(neng)(neng)表(biao)(biao)是采樣技(ji)術(shu)、微處理(li)技(ji)術(shu)、設計(ji)技(ji)術(shu)和經驗相結合的(de)(de)產物(wu),是跨學科的(de)(de)高技(ji)術(shu)產品。電能(neng)(neng)表(biao)(biao)制造商根據(ju)自身(shen)設計(ji)的(de)(de)理(li)解(jie)和應用技(ji)巧,實(shi)現電能(neng)(neng)表(biao)(biao)的(de)(de)各項功(gong)能(neng)(neng)。電能(neng)(neng)表(biao)(biao)產品上(shang),目前已經具備(bei)了多(duo)功(gong)能(neng)(neng)、網(wang)絡化、智(zhi)能(neng)(neng)化、數字化的(de)(de)需求(qiu),能(neng)(neng)夠(gou)滿足當前各種計(ji)量(liang)的(de)(de)要求(qiu),如有功(gong)計(ji)量(liang)、無功(gong)計(ji)量(liang)、需量(liang)計(ji)算,電網(wang)質量(liang)檢測、電網(wang)事(shi)件記(ji)錄等復(fu)雜功(gong)能(neng)(neng),并能(neng)(neng)夠(gou)作(zuo)為通訊從站(zhan)與中央控(kong)制主站(zhan)進行(xing)數據(ju)交互(hu)。
電能表分類
1、按用途:有功電(dian)(dian)能(neng)(neng)表(biao)(biao)、無功電(dian)(dian)能(neng)(neng)表(biao)(biao)、最大需量表(biao)(biao)、標準電(dian)(dian)能(neng)(neng)表(biao)(biao)、復費率分時電(dian)(dian)能(neng)(neng)表(biao)(biao)、預付(fu)費電(dian)(dian)能(neng)(neng)表(biao)(biao)(分投幣式(shi)(shi)、磁卡式(shi)(shi)、電(dian)(dian)卡式(shi)(shi))、損耗電(dian)(dian)能(neng)(neng)表(biao)(biao)、多功能(neng)(neng)電(dian)(dian)能(neng)(neng)表(biao)(biao)和(he)智能(neng)(neng)電(dian)(dian)能(neng)(neng)表(biao)(biao)。
2、按工(gong)作原(yuan)理:感應式(shi)(機(ji)械式(shi))、靜止(zhi)式(shi)(電(dian)子式(shi))、機(ji)電(dian)一體(ti)式(shi)(混(hun)合式(shi))。
3、按接入電源性質:交流表(biao)、直流表(biao)。
4、按結構(gou):整體式(shi)、分體式(shi)。
5、按接入相(xiang)線:單(dan)相(xiang)、三(san)相(xiang)三(san)線、三(san)相(xiang)四線電能表(biao)。
6、按準確級:普通安裝式電能(neng)表(0.2S、0.5S、0.2.0.5.1.0、2.0級)和攜帶式精密電能表(0.01、0.05、0.2級(ji))。
7、按安裝接(jie)(jie)線方式:直接(jie)(jie)接(jie)(jie)入(ru)式、間(jian)接(jie)(jie)接(jie)(jie)入(ru)式。
電能表型號
目前(qian),電(dian)能(neng)表的形式(shi)及功(gong)(gong)能(neng)是多(duo)種多(duo)樣的,各電(dian)能(neng)表品牌廠家(jia)在型號(hao)命(ming)名上也(ye)不盡完全相(xiang)同,普通(tong)有功(gong)(gong)電(dian)能(neng)表只用兩個(ge)字母(mu)表示其(qi)功(gong)(gong)能(neng)和(he)用途。有特殊功(gong)(gong)能(neng)或電(dian)子式(shi)的電(dian)能(neng)表多(duo)用三個(ge)字母(mu)表示其(qi)功(gong)(gong)能(neng)和(he)用途。舉例如(ru)下。
1、DD28表示單(dan)相電(dian)能表。第(di)一個字(zi)母D表示電(dian)能表,第(di)二個字(zi)母D表示單(dan)相,9Q為設(she)計(ji)序號。
2、DS862表(biao)示三相三線(xian)(xian)有功電(dian)能表(biao)。第一(yi)個字母(mu)(mu)D表(biao)示電(dian)能表(biao),第二個字母(mu)(mu)S表(biao)示三相三線(xian)(xian),86為設計序(xu)號,2為改(gai)進序(xu)號。
3、DT862表(biao)示(shi)三相(xiang)四(si)線有功電能表(biao)。D表(biao)示(shi)電能表(biao),T表(biao)示(shi)三相(xiang)四(si)線,86為(wei)設計(ji)序號,2表(biao)示(shi)改進序號。
4、叨表(biao)示(shi)直(zhi)流電(dian)能表(biao)。D表(biao)示(shi)電(dian)能表(biao),J表(biao)示(shi)直(zhi)流。
5、DB表示(shi)(shi)標準電(dian)能表。D表示(shi)(shi)電(dian)能表,B表示(shi)(shi)標準。
6、DZ表(biao)示(shi)最大需量電能(neng)表(biao)。D表(biao)示(shi)電能(neng)表(biao),z表(biao)示(shi)最大需量。
7、¤禿表示三(san)相三(san)線(xian)標準(zhun)電能表。D表示電能表,B表示標準(zhun),S表示三(san)相三(san)線(xian)。
8、DBT表(biao)(biao)(biao)(biao)示三(san)相四(si)線標準(zhun)電能表(biao)(biao)(biao)(biao)。D表(biao)(biao)(biao)(biao)示電能表(biao)(biao)(biao)(biao),B表(biao)(biao)(biao)(biao)示標準(zhun),T表(biao)(biao)(biao)(biao)示三(san)相四(si)線。
9、DX8表(biao)(biao)示無(wu)(wu)功(gong)電能表(biao)(biao)。D表(biao)(biao)示電能表(biao)(biao),X表(biao)(biao)示無(wu)(wu)功(gong),8為設計序號(hao)。
10、DTM31表(biao)(biao)示三(san)(san)相四(si)線脈(mo)(mo)沖(chong)電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)表(biao)(biao),D表(biao)(biao)示電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)表(biao)(biao),T表(biao)(biao)示三(san)(san)相四(si)線,M表(biao)(biao)示脈(mo)(mo)沖(chong),31為設(she)計(ji)序(xu)號(hao)。設(she)計(ji)序(xu)號(hao)為33的電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)表(biao)(biao)是具有(you)同樣功(gong)能(neng)(neng)(neng)(neng)的無功(gong)電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)表(biao)(biao)。該(gai)電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)表(biao)(biao)可(ke)用于工(gong)礦企業及各類營業單位計(ji)量有(you)功(gong)電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)或無功(gong)電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng)。可(ke)以(yi)遠距離采集(ji)脈(mo)(mo)沖(chong)信(xin)號(hao),編程控制調控電(dian)(dian)(dian)(dian)能(neng)(neng)(neng)(neng),節(jie)省人力,提(ti)高工(gong)作效率。
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)能表接入被(bei)測電(dian)(dian)路時(shi),電(dian)(dian)流(liu)(liu)(liu)線圈和(he)電(dian)(dian)壓(ya)線圈中(zhong)(zhong)就(jiu)有交(jiao)變(bian)(bian)(bian)電(dian)(dian)流(liu)(liu)(liu)流(liu)(liu)(liu)過(guo),這兩個(ge)交(jiao)變(bian)(bian)(bian)電(dian)(dian)流(liu)(liu)(liu)分(fen)別(bie)在它(ta)們的(de)鐵芯中(zhong)(zhong)產生(sheng)交(jiao)變(bian)(bian)(bian)的(de)磁(ci)(ci)通;交(jiao)變(bian)(bian)(bian)磁(ci)(ci)通穿過(guo)鋁(lv)(lv)(lv)(lv)盤(pan),在鋁(lv)(lv)(lv)(lv)盤(pan)中(zhong)(zhong)感(gan)應出渦(wo)流(liu)(liu)(liu);渦(wo)流(liu)(liu)(liu)又在磁(ci)(ci)場中(zhong)(zhong)受(shou)到(dao)力(li)(li)(li)的(de)作(zuo)用,從而(er)使鋁(lv)(lv)(lv)(lv)盤(pan)得到(dao)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)矩(ju)(ju)(主動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju))而(er)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)。負(fu)載(zai)消耗(hao)(hao)的(de)功率(lv)越(yue)(yue)(yue)(yue)大(da)(da),通過(guo)電(dian)(dian)流(liu)(liu)(liu)線圈的(de)電(dian)(dian)流(liu)(liu)(liu)越(yue)(yue)(yue)(yue)大(da)(da),鋁(lv)(lv)(lv)(lv)盤(pan)中(zhong)(zhong)感(gan)應出的(de)渦(wo)流(liu)(liu)(liu)也越(yue)(yue)(yue)(yue)大(da)(da),使鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)的(de)力(li)(li)(li)矩(ju)(ju)就(jiu)越(yue)(yue)(yue)(yue)大(da)(da)。即轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)矩(ju)(ju)的(de)大(da)(da)小(xiao)跟負(fu)載(zai)消耗(hao)(hao)的(de)功率(lv)成正(zheng)比。功率(lv)越(yue)(yue)(yue)(yue)大(da)(da),轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)矩(ju)(ju)也越(yue)(yue)(yue)(yue)大(da)(da),鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)也就(jiu)越(yue)(yue)(yue)(yue)快。鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)時(shi),又受(shou)到(dao)永久磁(ci)(ci)鐵產生(sheng)的(de)制(zhi)(zhi)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)的(de)作(zuo)用,制(zhi)(zhi)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)與(yu)(yu)主動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)方向相反;制(zhi)(zhi)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)的(de)大(da)(da)小(xiao)與(yu)(yu)鋁(lv)(lv)(lv)(lv)盤(pan)的(de)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)速成正(zheng)比,鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)得越(yue)(yue)(yue)(yue)快,制(zhi)(zhi)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)也越(yue)(yue)(yue)(yue)大(da)(da)。當主動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)與(yu)(yu)制(zhi)(zhi)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)力(li)(li)(li)矩(ju)(ju)達到(dao)暫(zan)時(shi)平衡時(shi),鋁(lv)(lv)(lv)(lv)盤(pan)將勻速轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)。負(fu)載(zai)所消耗(hao)(hao)的(de)電(dian)(dian)能與(yu)(yu)鋁(lv)(lv)(lv)(lv)盤(pan)的(de)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)數成正(zheng)比。鋁(lv)(lv)(lv)(lv)盤(pan)轉(zhuan)(zhuan)(zhuan)(zhuan)(zhuan)動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)時(shi),帶動(dong)(dong)(dong)(dong)(dong)(dong)(dong)(dong)計數器(qi),把所消耗(hao)(hao)的(de)電(dian)(dian)能指(zhi)示出來。這就(jiu)是電(dian)(dian)能表工作(zuo)的(de)簡單過(guo)程。
電能表接線圖
三相(xiang)電能表接線(xian)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6次方在數值上表示(shi)功(gong)率1kw的用電器工作1h所消耗的電能)
無功電能表kvar·h
字輪計度器(qi)窗口(液晶顯示窗口):
整數位(wei)和小數位(wei)不(bu)同顏色,中間小數點;各(ge)字輪(lun)有倍乘系數(無(wu)小數點時)多功能表(biao)液晶顯示有整數位(wei)和小數位(wei)兩位(wei)。
準確度等級:
相(xiang)對誤差,用(yong)置于圓圈內的數字表(biao)示
標定電(dian)流和(he)額定最大電(dian)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(shi)三相三線(xian):3×380V
B、直接接入式(shi)三(san)相四(si)線(xian):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(du)表接(jie)線(xian)較復雜,接(jie)線(xian)前必(bi)須分清電(dian)度(du)表的電(dian)壓端子和電(dian)流端子,然后按(an)照說明書對號接(jie)入。
2、電度表只有在(zai)額(e)(e)定(ding)電壓、額(e)(e)定(ding)電流20~120%額(e)(e)定(ding)頻率50赫茲的條件(jian)下工(gong)作,才能保(bao)證準確度。
3、電度表不宜在小于規(gui)定電流(liu)的5%和(he)大約定電流(liu)的150%情況(kuang)下工作。
4、停用半年的電度(du)表應重(zhong)新校準
5、電度(du)表安裝時,要距熱(re)力系統0.5米(mi)以上,距地面0.7~2.0米(mi),并且要力求垂直安裝。
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:取下肢(zhi)術接線蓋后(hou)拉下總閘刀(dao),將(jiang)電源導線全部拆下,重新用刀(dao)將(jiang)線頭殘留物刮干凈,裝入接線柱內(nei),擰緊全部螺絲即可(ke)以(yi)排(pai)除故障(zhang)。
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(di)清除接線(xian)(xian)盒(he)內的油污及更(geng)換導線(xian)(xian)。有時當(dang)用電(dian)(dian)(dian)設備超過(guo)電(dian)(dian)(dian)表(biao)實際安培值時,不(bu)僅接線(xian)(xian)盒(he)會損壞(huai),電(dian)(dian)(dian)表(biao)也有可能被強電(dian)(dian)(dian)流擊(ji)毀(hui),所以當(dang)發現表(biao)的額(e)定電(dian)(dian)(dian)流與(yu)實際所用電(dian)(dian)(dian)器的總負荷相差很大時,應錯開使用時間或更(geng)換電(dian)(dian)(dian)度表(biao),以防電(dian)(dian)(dian)表(biao)被擊(ji)毀(hui)或發生(sheng)電(dian)(dian)(dian)氣(qi)火災。
2、鋁盤停轉或不跳字
電(dian)(dian)度表是(shi)一(yi)種精密計(ji)量儀(yi)表,它在出廠前(qian)都是(shi)經過嚴格(ge)校驗(yan)的,其靈(ling)敏度和可靠性、穩定性應達到(dao)一(yi)定的標(biao)準。當負(fu)荷電(dian)(dian)流小(xiao)于0.025A時(shi),電(dian)(dian)表鋁(lv)盤(pan)不轉(zhuan)動、不跳字屬正(zheng)常范圍,如果在較(jiao)大負(fu)荷時(shi)仍不轉(zhuan)動,很可能(neng)是(shi)鋁(lv)盤(pan)被卡住,鋁(lv)盤(pan)已變形(xing)或電(dian)(dian)磁機構失靈(ling)等(deng)問題,應及時(shi)送檢(jian)。
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(yi)般來(lai)說,當電源電壓為額定值的80%至(zhi)110%時,電表鋁(lv)盤的轉(zhuan)(zhuan)動(dong)不會超過一(yi)圈(quan)屬于正常范圍(即轉(zhuan)(zhuan)盤順時針(zhen)方向轉(zhuan)(zhuan)動(dong)一(yi)圈(quan)),但(dan)若鋁(lv)盤微微轉(zhuan)(zhuan)動(dong)不止(zhi),則說明電表線路有漏(lou)電存在,應(ying)請電工檢查處(chu)理。如果(guo)沒有漏電(dian)(dian)存在,那(nei)就(jiu)是電(dian)(dian)表(biao)自身的故(gu)障,應(ying)及時送電(dian)(dian)力(li)部門檢(jian)修或(huo)換新表(biao)。
4、運行時產生“吱吱”響聲
電(dian)度表在運行(xing)時(shi)(shi),有輕(qing)微的“嗡嗡”聲,屬于正常現象。但如果表內產(chan)生(sheng)不規(gui)則(ze)的雜亂響(xiang)聲,則(ze)是表內部的某些配件(jian)(jian)老化、電(dian)磁(ci)場部分(fen)元件(jian)(jian)松(song)動,或轉動齒輪缺油等原因(yin)所引起。應送電(dian)力部門(men)校驗(yan)并更換易損配件(jian)(jian)。有時(shi)(shi),當(dang)電(dian)表處于嚴重(zhong)超負荷運行(xing)時(shi)(shi),也會產(chan)生(sheng)不規(gui)則(ze)的響(xiang)聲,應及時(shi)(shi)關閉部分(fen)電(dian)器,以防損壞(huai)電(dian)表。