發電機逆功率保護學習
      發電(dian)機逆功率保護

  發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)逆(ni)(ni)功(gong)(gong)率(lv)保(bao)(bao)護(hu)又稱功(gong)(gong)率(lv)方向(xiang)(xiang)保(bao)(bao)護(hu)。一(yi)般而(er)言，發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)的(de)功(gong)(gong)率(lv)方向(xiang)(xiang)應該為(wei)由發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)流向(xiang)(xiang)母線，但是當(dang)發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)失磁或其(qi)他(ta)某(mou)種原因，發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)有可能變為(wei)電(dian)動(dong)機(ji)(ji)運行，即從系統中(zhong)吸取有功(gong)(gong)功(gong)(gong)率(lv)。這就是逆(ni)(ni)功(gong)(gong)率(lv)。當(dang)逆(ni)(ni)功(gong)(gong)率(lv)達到(dao)一(yi)定值時，發(fa)(fa)(fa)(fa)電(dian)機(ji)(ji)的(de)保(bao)(bao)護(hu)動(dong)作(zuo)，或動(dong)作(zuo)于發(fa)(fa)(fa)(fa)信(xin)號或動(dong)作(zuo)于跳閘。

  1、概述(shu)說明

  并(bing)網運行(xing)(xing)的汽輪(lun)(lun)發電(dian)機(ji)(ji)(ji)，在汽輪(lun)(lun)機(ji)(ji)(ji)的主汽門關閉之(zhi)后，便(bian)作為(wei)同步電(dian)動(dong)機(ji)(ji)(ji)運行(xing)(xing)：吸收有功(gong)(gong)功(gong)(gong)率(lv)(lv)而拖著汽輪(lun)(lun)機(ji)(ji)(ji)轉動(dong)，可向系統發出無功(gong)(gong)功(gong)(gong)率(lv)(lv)。由于汽輪(lun)(lun)機(ji)(ji)(ji)主汽門已關閉，汽機(ji)(ji)(ji)尾部葉片(pian)與殘留蒸(zheng)汽產生摩擦(ca)而形(xing)成(cheng)鼓風損耗，長期運行(xing)(xing)過熱(re)而損壞。燃氣輪(lun)(lun)機(ji)(ji)(ji)和(he)水輪(lun)(lun)機(ji)(ji)(ji)也主要是對原動(dong)機(ji)(ji)(ji)的損害。發電(dian)機(ji)(ji)(ji)逆功(gong)(gong)率(lv)(lv)保護(hu)主要保護(hu)汽輪(lun)(lun)機(ji)(ji)(ji)不受損害。

  對汽(qi)輪(lun)機(ji)逆功(gong)率保護的整定計算，就是(shi)要確定該保護的動(dong)作功(gong)率Pdz及動(dong)作延時t。

  1、動(dong)作(zuo)(zuo)(zuo)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)Pdz的整(zheng)定 汽(qi)輪(lun)發電(dian)(dian)(dian)機(ji)(ji)(ji)逆功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)保(bao)護的動(dong)作(zuo)(zuo)(zuo)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)可(ke)按(an)下式計算：Pdz=(Krel*P1)/η Pdz-逆功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)保(bao)護的動(dong)作(zuo)(zuo)(zuo)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv) Krel-可(ke)靠(kao)系數，取(qu)(qu)0.8 P1-主(zhu)汽(qi)門關閉后，汽(qi)輪(lun)機(ji)(ji)(ji)維持同步(bu)轉速旋轉所(suo)消耗的功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)，該功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)的大小除與汽(qi)輪(lun)機(ji)(ji)(ji)的結(jie)(jie)(jie)構及(ji)容量(liang)有關之外，還與汽(qi)輪(lun)發電(dian)(dian)(dian)機(ji)(ji)(ji)的主(zhu)蒸汽(qi)系統的結(jie)(jie)(jie)構(管(guan)道(dao)結(jie)(jie)(jie)構及(ji)有無旁路(lu)管(guan)道(dao)等(deng))有關，一般取(qu)(qu)額(e)定功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)的1.5~2% η-發電(dian)(dian)(dian)機(ji)(ji)(ji)拖動(dong)汽(qi)輪(lun)發電(dian)(dian)(dian)機(ji)(ji)(ji)旋轉時的效(xiao)率(lv)(lv)(lv)(lv)，取(qu)(qu)0.98~0.99 所(suo)以：Pdz≈(1.2~1.6%)PN PN-發電(dian)(dian)(dian)機(ji)(ji)(ji)的額(e)定功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)。 實際中，Pdz=可(ke)取(qu)(qu)1~1.5%PN。

  2、動(dong)(dong)作(zuo)延時(shi)(shi)發電機(ji)逆功(gong)率保護的動(dong)(dong)作(zuo)延時(shi)(shi)，應按照(zhao)(zhao)汽(qi)輪發電機(ji)主汽(qi)門(men)(men)關閉(bi)后允許運(yun)(yun)(yun)行(xing)的時(shi)(shi)間來整(zheng)定，該允許時(shi)(shi)間一般(ban)為10~15min。計算(suan)及運(yun)(yun)(yun)行(xing)實踐表明，當汽(qi)輪機(ji)蒸(zheng)汽(qi)系統有(you)旁路管(guan)道時(shi)(shi)，允許運(yun)(yun)(yun)行(xing)時(shi)(shi)間還要長(chang)一些。 因此(ci)，若按照(zhao)(zhao)汽(qi)輪機(ji)主汽(qi)門(men)(men)關閉(bi)之后允許運(yun)(yun)(yun)行(xing)的時(shi)(shi)間來整(zheng)定保護的動(dong)(dong)作(zuo)延時(shi)(shi)，可取5~10min。動(dong)(dong)作(zuo)后作(zuo)用(yong)于(yu)解列(lie)滅磁。

  另外，投運的大型汽輪發電(dian)機，多采用逆(ni)功率保護(hu)去啟動程序跳閘回(hui)路，此時，動作時間(jian)通常取1~2s。 對于程控逆(ni)功率保護(hu)，由于動作時間(jian)短，在主汽門點閉后很短的時間(jian)內，由于汽輪機及(ji)發電(dian)機的慣(guan)性(xing)，實際逆(ni)功率可能(neng)很小，因此逆(ni)功率的定值不(bu)應大于1%PN。

  2、原理介紹

  當發電(dian)機(ji)出現逆功(gong)率(lv)(lv)(外部功(gong)率(lv)(lv)指向發電(dian)機(ji)，也就是(shi)發電(dian)機(ji)變(bian)成電(dian)動機(ji)工(gong)況(kuang))，逆功(gong)率(lv)(lv)保護動作斷路器跳閘。需要采集三相電(dian)壓(ya)和(he)二(er)相電(dian)流(liu)信號。

  由(you)于(yu)一(yi)次(ci)能(neng)源形(xing)態的不(bu)同(tong)(tong)，可(ke)(ke)以制成(cheng)不(bu)同(tong)(tong)的發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)。利(li)用(yong)(yong)水(shui)利(li)資(zi)源和(he)(he)水(shui)輪(lun)機(ji)(ji)(ji)(ji)配合(he)，可(ke)(ke)以制成(cheng)水(shui)輪(lun)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji);由(you)于(yu)水(shui)庫容(rong)量(liang)和(he)(he)水(shui)頭落差(cha)高(gao)低(di)不(bu)同(tong)(tong)，可(ke)(ke)以制成(cheng)容(rong)量(liang)和(he)(he)轉速各異的水(shui)輪(lun)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)。利(li)用(yong)(yong)煤、石油(you)等(deng)資(zi)源，和(he)(he)鍋爐，渦輪(lun)蒸汽(qi)機(ji)(ji)(ji)(ji)配合(he)，可(ke)(ke)以制成(cheng)汽(qi)輪(lun)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)，這種發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)多為高(gao)速電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)(3000rpm)。 此外(wai)還有利(li)用(yong)(yong)太(tai)陽能(neng)、風(feng)能(neng)、原子能(neng)、地熱、潮汐、生物能(neng)等(deng)能(neng)量(liang)的各類(lei)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)。 此外(wai)，由(you)于(yu)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)工作原理不(bu)同(tong)(tong)又(you)分作直(zhi)流發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)，異步(bu)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)和(he)(he)同(tong)(tong)步(bu)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)。在廣泛(fan)使用(yong)(yong)的大型(xing)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)都(dou)是同(tong)(tong)步(bu)發(fa)(fa)(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)。

  何為(wei)逆(ni)功率?

  眾所周知，發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)的功(gong)(gong)率方(fang)向(xiang)應該由(you)(you)發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)方(fang)向(xiang)流向(xiang)系統方(fang)向(xiang)。但由(you)(you)于某種原因(yin)，當汽輪(lun)機(ji)(ji)(ji)失去原動(dong)力，而發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)出口(kou)開關又未能跳閘，則功(gong)(gong)率方(fang)向(xiang)變(bian)(bian)為(wei)由(you)(you)系統流向(xiang)發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)，即(ji)發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)變(bian)(bian)為(wei)電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)在運行。此(ci)(ci)時發(fa)(fa)(fa)電(dian)(dian)(dian)機(ji)(ji)(ji)從系統中吸取有功(gong)(gong)功(gong)(gong)率，此(ci)(ci)即(ji)為(wei)逆功(gong)(gong)率。

  逆功率的危害

  發電(dian)機逆(ni)功率(lv)保護是汽(qi)輪機由(you)于某種原因導致(zhi)主汽(qi)門(men)關閉而失去(qu)原動力(li)時，發電(dian)機變為電(dian)動機帶動汽(qi)輪機旋(xuan)轉(zhuan)，汽(qi)輪機葉片在(zai)無(wu)蒸汽(qi)情(qing)況(kuang)下高速旋(xuan)轉(zhuan)會引起(qi)鼓風摩擦(ca)，特別是在(zai)末級葉片可能會引起(qi)過熱(re)，導致(zhi)轉(zhuan)子(zi)葉片的(de)損壞事故。

  所(suo)以說(shuo)逆功(gong)率保(bao)護實則是對汽(qi)輪機無蒸(zheng)汽(qi)運行的保(bao)護。

  發電機的程序逆(ni)功率保護(hu)

  發(fa)(fa)(fa)電(dian)(dian)機(ji)(ji)程(cheng)序逆功率保護(hu)主要是防止發(fa)(fa)(fa)電(dian)(dian)機(ji)(ji)在帶(dai)有一定負荷的(de)情(qing)況(kuang)下，突然跳開發(fa)(fa)(fa)電(dian)(dian)機(ji)(ji)出(chu)口(kou)開關(guan)(guan)而汽(qi)輪(lun)機(ji)(ji)主汽(qi)門(men)(men)又未能全(quan)部(bu)關(guan)(guan)閉(bi)的(de)情(qing)況(kuang)。在此情(qing)況(kuang)下，汽(qi)輪(lun)發(fa)(fa)(fa)電(dian)(dian)機(ji)(ji)組極易(yi)發(fa)(fa)(fa)生超(chao)速，甚(shen)至(zhi)飛車。為(wei)避(bi)免(mian)此種情(qing)況(kuang)，對于非短路故障的(de)某些保護(hu)，動(dong)(dong)作(zuo)信號發(fa)(fa)(fa)出(chu)后，先作(zuo)用于關(guan)(guan)閉(bi)汽(qi)輪(lun)機(ji)(ji)主汽(qi)門(men)(men)，待發(fa)(fa)(fa)電(dian)(dian)機(ji)(ji)逆功率繼電(dian)(dian)器動(dong)(dong)作(zuo)后，與主汽(qi)門(men)(men)關(guan)(guan)閉(bi)的(de)信號組成(cheng)與門(men)(men)，經一短時限組成(cheng)程(cheng)序逆功率保護(hu)，動(dong)(dong)作(zuo)作(zuo)用于全(quan)停(ting)。

  逆功(gong)率保(bao)護(hu)與程序(xu)逆功(gong)率保(bao)護(hu)的區別(bie)

  逆(ni)功率(lv)保護是(shi)為(wei)了防止逆(ni)功率(lv)后，發電機(ji)(ji)變為(wei)電動(dong)(dong)機(ji)(ji)，帶動(dong)(dong)汽輪(lun)機(ji)(ji)旋轉，造成汽輪(lun)機(ji)(ji)的損壞。歸根到底，是(shi)怕原動(dong)(dong)機(ji)(ji)動(dong)(dong)力不足，反被系統帶著(zhu)跑(pao)!

  程序逆功(gong)率保(bao)護是為了防止發電機組(zu)突(tu)然解列后(hou)，主汽門未(wei)完全關閉，導(dao)(dao)致汽輪機超(chao)速，從而利用逆功(gong)率來規避。歸根到(dao)底，是怕原動(dong)機動(dong)力太足導(dao)(dao)致機組(zu)超(chao)速!

  所以說(shuo)嚴格意義上來(lai)說(shuo)，逆功(gong)率保(bao)護(hu)(hu)是發電(dian)機(ji)繼電(dian)保(bao)護(hu)(hu)的(de)一種，但(dan)主要是保(bao)護(hu)(hu)汽輪機(ji)。而(er)程(cheng)序(xu)逆功(gong)率保(bao)護(hu)(hu)不是一種保(bao)護(hu)(hu)而(er)是為了實現程(cheng)序(xu)跳閘而(er)設置的(de)動作過程(cheng)，也叫程(cheng)序(xu)跳閘，一般應用于停機(ji)方式。

  關鍵(jian)的是逆功率只要(yao)定(ding)值(zhi)達到(dao)就會跳閘，而(er)程序逆功率除了定(ding)值(zhi)達到(dao)，還要(yao)求汽(qi)機主汽(qi)門關閉，所以說(shuo)在機組啟動(dong)過程中(zhong)并(bing)網瞬(shun)間，一定(ding)要(yao)避免逆功率動(dong)作。

維曼發電機租賃(lin)