繼電保護的基本知識
一、繼電保護的任務和要求
1.繼電保護的任務
為保證供(gong)(gong)配(pei)電(dian)(dian)系統(tong)(tong)的(de)安全運行，避免過(guo)(guo)負荷和短路(lu)(lu)引起(qi)的(de)過(guo)(guo)電(dian)(dian)流(liu)對(dui)系統(tong)(tong)的(de)影響(xiang)，在供(gong)(gong)配(pei)電(dian)(dian)系統(tong)(tong)中(zhong)要裝(zhuang)有(you)不同類(lei)型的(de)過(guo)(guo)電(dian)(dian)流(liu)保護(hu)(hu)(hu)(hu)裝(zhuang)置。常用的(de)過(guo)(guo)電(dian)(dian)流(liu)保護(hu)(hu)(hu)(hu)裝(zhuang)置有(you)熔斷(duan)器(qi)保護(hu)(hu)(hu)(hu)、低壓斷(duan)路(lu)(lu)器(qi)保護(hu)(hu)(hu)(hu)和繼電(dian)(dian)保護(hu)(hu)(hu)(hu)。其中(zhong)繼電(dian)(dian)保護(hu)(hu)(hu)(hu)廣泛應用于高壓供(gong)(gong)配(pei)電(dian)(dian)系統(tong)(tong)中(zhong)，其保護(hu)(hu)(hu)(hu)功能很多，而且是(shi)實現(xian)供(gong)(gong)配(pei)電(dian)(dian)自動化(hua)的(de)基礎。
繼電保護(hu)裝(zhuang)置(zhi)(zhi)是指能反映供配電系統(tong)中(zhong)電氣設備發(fa)生的故障或不正常工作(zuo)狀態(tai)，并能動(dong)作(zuo)于(yu)斷(duan)路器跳(tiao)閘或起動(dong)信(xin)號裝(zhuang)置(zhi)(zhi)發(fa)出預報信(xin)號的一種自動(dong)裝(zhuang)置(zhi)(zhi)。
繼電保護的(de)主要(yao)任(ren)務如下：
（1）自(zi)動、迅速(su)、有選擇性地將故障(zhang)元件從(cong)供(gong)配電(dian)(dian)系統切除，使其(qi)他非(fei)故障(zhang)部分(fen)迅速(su)恢復(fu)正常供(gong)電(dian)(dian)；
（2）能正確反(fan)映電氣設備(bei)的不(bu)正常(chang)運行(xing)狀態(tai)，發出預(yu)報(bao)信(xin)號，以便操作人員采取措施(shi)，恢復電氣設備(bei)正常(chang)工作；
（3）與供配(pei)電(dian)系統的自動裝置(zhi)(zhi)（如自動重(zhong)合(he)閘(zha)裝置(zhi)(zhi)、備用(yong)電(dian)源自動投(tou)入裝置(zhi)(zhi)等）配(pei)合(he)，提高供電(dian)系統的運行(xing)可靠(kao)性。
建(jian)筑供配電系統繼電保護的特點是(shi)簡單(dan)、有(you)效、可靠，且(qie)有(you)較強的抗干擾能力。
2.對繼(ji)電保護(hu)的基(ji)本(ben)要求
繼電保護的(de)(de)設計應以合理的(de)(de)運行方式和可能的(de)(de)故障類型為依據，并應滿足(zu)選擇性、速動性、可靠性、靈敏性四項基(ji)本要(yao)求(qiu)。
(1)選擇性
選擇性(xing)是指(zhi)首(shou)先(xian)由故(gu)(gu)障(zhang)設備或線路本(ben)身的保(bao)護切(qie)除故(gu)(gu)障(zhang)。當(dang)供電系(xi)統發生短路故(gu)(gu)障(zhang)時，繼電保(bao)護裝置(zhi)動作，只切(qie)除故(gu)(gu)障(zhang)元件，并使停電范圍(wei)最(zui)小，以減小故(gu)(gu)障(zhang)停電造成的影響。保(bao)護裝置(zhi)這(zhe)種能挑選故(gu)(gu)障(zhang)元件的能力(li)稱為(wei)保(bao)護的選擇性(xing)。
(2)速動性
為了減(jian)小由于故(gu)障(zhang)(zhang)引(yin)起的(de)(de)(de)(de)損失，減(jian)少用(yong)戶在(zai)故(gu)障(zhang)(zhang)時低電(dian)壓下的(de)(de)(de)(de)工作(zuo)時間，以(yi)及提(ti)高電(dian)力(li)系(xi)統(tong)(tong)運行的(de)(de)(de)(de)穩(wen)定性(xing)，要求繼電(dian)保(bao)護裝置(zhi)在(zai)發生(sheng)故(gu)障(zhang)(zhang)時盡快動作(zuo)并將故(gu)障(zhang)(zhang)切(qie)除。快速地(di)切(qie)除故(gu)障(zhang)(zhang)部分可以(yi)防止(zhi)故(gu)障(zhang)(zhang)擴大，減(jian)輕(qing)故(gu)障(zhang)(zhang)電(dian)流對電(dian)氣(qi)設備的(de)(de)(de)(de)損壞(huai)程度，加(jia)快供(gong)電(dian)系(xi)統(tong)(tong)電(dian)壓的(de)(de)(de)(de)恢復，提(ti)高供(gong)電(dian)系(xi)統(tong)(tong)運行的(de)(de)(de)(de)可靠性(xing)。
(3)可靠性
可(ke)(ke)靠性(xing)是指保護(hu)裝置應該動(dong)作時動(dong)作，不(bu)(bu)應該動(dong)作時不(bu)(bu)動(dong)作。為保證可(ke)(ke)靠性(xing)，宜選(xuan)用盡可(ke)(ke)能(neng)簡(jian)單的保護(hu)方式，采(cai)用可(ke)(ke)靠的元件(jian)和(he)盡可(ke)(ke)能(neng)簡(jian)單的回路構成性(xing)能(neng)良好的裝置，并應有必要的檢測、閉鎖和(he)雙重化等措(cuo)施。保護(hu)裝置應便(bian)于(yu)整定、調試和(he)運行維護(hu)。
(4)靈敏性
靈敏性是指繼電(dian)保(bao)護(hu)(hu)(hu)(hu)在(zai)其保(bao)護(hu)(hu)(hu)(hu)范圍內對發生故障(zhang)或不正常工作(zuo)狀態時的(de)(de)(de)反應(ying)能力。過電(dian)流(liu)保(bao)護(hu)(hu)(hu)(hu)的(de)(de)(de)靈敏度SP用其保(bao)護(hu)(hu)(hu)(hu)區內在(zai)電(dian)力系統(tong)為(wei)最小運行方式時的(de)(de)(de)最小短路電(dian)流(liu)Ik，min與保(bao)護(hu)(hu)(hu)(hu)裝置一(yi)次動(dong)作(zuo)電(dian)流(liu)，即(ji)保(bao)護(hu)(hu)(hu)(hu)裝置動(dong)作(zuo)電(dian)流(liu)換(huan)算到一(yi)次電(dian)路的(de)(de)(de)值，OP，1的(de)(de)(de)比值來表(biao)示，即(ji)SP=Ik，min/IOP，1
對不(bu)同作用(yong)的(de)保(bao)護裝置和被保(bao)護設備，所要求的(de)靈敏度是(shi)不(bu)同的(de)，在《電力裝置的(de)繼電保(bao)護和自動裝置設計技術(shu)規(gui)范(fan)》(GB50062;1992)中都有規(gui)定(ding)。
另(ling)外,上(shang)述介紹的四項基(ji)本(ben)要求對(dui)于一個具(ju)體的保(bao)(bao)護(hu)裝(zhuang)置不一定都是同等重(zhong)要的，而(er)應有所側(ce)重(zhong)。例如，電(dian)力(li)變壓器是供(gong)配電(dian)系統(tong)中最關(guan)鍵的設備，對(dui)其保(bao)(bao)護(hu)裝(zhuang)置的靈敏度要求較(jiao)高；而(er)對(dui)一般電(dian)力(li)線路的保(bao)(bao)護(hu)裝(zhuang)置，就要求其選擇性較(jiao)高。
二、繼電保護的基本原理
電(dian)(dian)(dian)(dian)(dian)力系統發生故障時(shi)會(hui)引起電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的增加、電(dian)(dian)(dian)(dian)(dian)壓(ya)的降低(di)以及電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)與電(dian)(dian)(dian)(dian)(dian)壓(ya)間相位的變化，因此，電(dian)(dian)(dian)(dian)(dian)力系統中(zhong)所(suo)采用的各(ge)種繼電(dian)(dian)(dian)(dian)(dian)保護(hu)大多數是利用故障時(shi)物理量與正常(chang)運行時(shi)物理量的差別(bie)來構成(cheng)的，例如(ru)，反(fan)映電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)增大的過(guo)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)保護(hu)、反(fan)映電(dian)(dian)(dian)(dian)(dian)壓(ya)降低(di)(或升(sheng)高)的低(di)電(dian)(dian)(dian)(dian)(dian)壓(ya)(或過(guo)電(dian)(dian)(dian)(dian)(dian)壓(ya))保護(hu)等。
繼電(dian)(dian)保(bao)護(hu)原理結(jie)構方(fang)框圖如圖1所(suo)示(shi)。它由三部(bu)分(fen)(fen)組(zu)成，（1）測量(liang)(liang)部(bu)分(fen)(fen);;用來測量(liang)(liang)被保(bao)護(hu)設備輸(shu)(shu)入的(de)有關信(xin)(xin)號(電(dian)(dian)流、電(dian)(dian)壓)等，并和已給定的(de)整定值進(jin)行(xing)比較判斷(duan)是否應該起動；（2）邏(luo)(luo)輯(ji)部(bu)分(fen)(fen);;根據(ju)測量(liang)(liang)部(bu)分(fen)(fen)各(ge)輸(shu)(shu)出(chu)量(liang)(liang)的(de)大小、性質及(ji)其組(zu)合(he)或輸(shu)(shu)出(chu)順序(xu)，使保(bao)護(hu)裝(zhuang)置按照(zhao)一(yi)定的(de)邏(luo)(luo)輯(ji)程序(xu)工作(zuo)，并將信(xin)(xin)號傳輸(shu)(shu)給執行(xing)部(bu)分(fen)(fen)；（3）執行(xing)部(bu)分(fen)(fen);;根據(ju)邏(luo)(luo)輯(ji)部(bu)分(fen)(fen)傳輸(shu)(shu)的(de)信(xin)(xin)號，最后完成保(bao)護(hu)裝(zhuang)置所(suo)負擔(dan)的(de)任務，給出(chu)跳閘或信(xin)(xin)號脈沖。
如圖2所示為線(xian)(xian)路(lu)(lu)(lu)(lu)過電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)保(bao)護(hu)基本原(yuan)理(li)示意圖，用(yong)以說明繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)的(de)(de)(de)(de)(de)組成(cheng)和基本原(yuan)理(li)。圖2中(zhong)，KA的(de)(de)(de)(de)(de)線(xian)(xian)圈(quan)接(jie)(jie)于被(bei)保(bao)護(hu)線(xian)(xian)路(lu)(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)互感(gan)器(qi)TA的(de)(de)(de)(de)(de)二次(ci)(ci)回路(lu)(lu)(lu)(lu)，即保(bao)護(hu)的(de)(de)(de)(de)(de)測量回路(lu)(lu)(lu)(lu)，它監視(shi)被(bei)保(bao)護(hu)線(xian)(xian)路(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)運行狀(zhuang)態，測量線(xian)(xian)路(lu)(lu)(lu)(lu)中(zhong)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)(de)(de)(de)大(da)(da)(da)(da)小。在正常(chang)運行情況下，當(dang)(dang)線(xian)(xian)路(lu)(lu)(lu)(lu)中(zhong)通過最大(da)(da)(da)(da)負(fu)荷電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)時，繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)不動作(zuo)；當(dang)(dang)被(bei)保(bao)護(hu)線(xian)(xian)路(lu)(lu)(lu)(lu)K點發生短(duan)(duan)路(lu)(lu)(lu)(lu)時，線(xian)(xian)路(lu)(lu)(lu)(lu)上的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)突(tu)然增(zeng)大(da)(da)(da)(da)，電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)互感(gan)器(qi)TA二次(ci)(ci)側的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)也(ye)按變比相應增(zeng)大(da)(da)(da)(da)，當(dang)(dang)通過電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)KA的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)大(da)(da)(da)(da)于其(qi)整(zheng)定值(zhi)時，繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)立即動作(zuo)，觸點閉合，接(jie)(jie)通邏輯(ji)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)中(zhong)KT的(de)(de)(de)(de)(de)線(xian)(xian)圈(quan)回路(lu)(lu)(lu)(lu)，時間(jian)繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)起動并根據短(duan)(duan)路(lu)(lu)(lu)(lu)故障(zhang)持(chi)續(xu)的(de)(de)(de)(de)(de)時間(jian)作(zuo)出保(bao)護(hu)動作(zuo)的(de)(de)(de)(de)(de)邏輯(ji)判斷(duan)(duan)，時間(jian)繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)KT動作(zuo)，其(qi)延時觸點閉合，接(jie)(jie)通執行回路(lu)(lu)(lu)(lu)中(zhong)的(de)(de)(de)(de)(de)信號繼(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)KS和斷(duan)(duan)路(lu)(lu)(lu)(lu)器(qi)QF的(de)(de)(de)(de)(de)跳閘線(xian)(xian)圈(quan)回路(lu)(lu)(lu)(lu)，使斷(duan)(duan)路(lu)(lu)(lu)(lu)器(qi)跳閘，切除短(duan)(duan)路(lu)(lu)(lu)(lu)故障(zhang)。
三、斷電器的構成和分類
1.繼電器的作用
繼電(dian)器(qi)是一種(zhong)在(zai)其輸(shu)入的物理量(電(dian)氣量或非(fei)電(dian)氣量)達到(dao)規定(ding)值(zhi)時(shi)，其電(dian)氣輸(shu)出電(dian)路被(bei)接通或分(fen)斷的自動電(dian)器(qi)。
繼電器一(yi)般由(you)感(gan)受元(yuan)件、比較元(yuan)件和執行元(yuan)件三個(ge)主要部(bu)分組成。
（1）感受元件將感受到的物理量(如(ru)電流、電壓(ya))的變化(hua)情況綜合(he)后送(song)到比較元件。
（2）比較(jiao)元件(jian)將感受元件(jian)送(song)來(lai)的(de)物(wu)理(li)量與預(yu)先給定的(de)物(wu)理(li)量(整(zheng)定值)相比較(jiao)，根據(ju)比較(jiao)的(de)結果向執行元件(jian)發出指令。
（3）執行元件根(gen)據來自(zi)比較元件的指令自(zi)動完成繼電器(qi)所擔負的任務，例如向斷路器(qi)發出跳閘脈沖或(huo)進行其他操作。
2.繼電器的分類
繼電(dian)器的種類(lei)很多(duo)，目(mu)前一般(ban)分類(lei)方(fang)法(fa)如下(xia)：
（1）按繼(ji)電器(qi)動作和構成原理(li)可分為電磁型(xing)(xing)、感應型(xing)(xing)、整流型(xing)(xing)、極化(hua)型(xing)(xing)、半導(dao)體(ti)型(xing)(xing)、熱力型(xing)(xing)等繼(ji)電器(qi)。
（2）按照繼電器(qi)反(fan)映物理量(liang)的性(xing)質(zhi)可分為(wei)電流(liu)、電壓(ya)、時間(jian)、信號、功(gong)率(lv)、方向、阻抗、頻率(lv)等繼電器(qi)。
繼電(dian)(dian)器(qi)又可分為(wei)反映電(dian)(dian)氣量(liang)增加和(he)反映電(dian)(dian)氣量(liang)減(jian)少兩大類。前者為(wei)過(guo)量(liang)繼電(dian)(dian)器(qi)，如(ru)過(guo)電(dian)(dian)流繼電(dian)(dian)器(qi)等，后(hou)者為(wei)欠量(liang)繼電(dian)(dian)器(qi)，如(ru)欠電(dian)(dian)壓(ya)繼電(dian)(dian)器(qi)等。
除此之外，還有(you)一(yi)類反映非電(dian)氣量參數而動作的(de)繼電(dian)器(qi)(qi)，如氣體，瓦斯，繼電(dian)器(qi)(qi)、溫度繼電(dian)器(qi)(qi)等。
3.繼(ji)電器的表示方法(fa)
我(wo)國繼(ji)電器型號(hao)的編制是以漢語拼音字母表(biao)示(shi)的，由(you)動作(zuo)原理代(dai)號(hao)、主(zhu)要功能(neng)代(dai)號(hao)、設計序號(hao)及主(zhu)要規格(ge)代(dai)號(hao)所組(zu)成(cheng)，其表(biao)示(shi)形式如(ru)下(xia)：
設計(ji)(ji)序(xu)號(hao)(hao)及主要規(gui)格(ge)用(yong)阿拉(la)伯數字表(biao)示(shi)，繼(ji)電(dian)器的(de)主要規(gui)格(ge)代號(hao)(hao)常用(yong)來表(biao)示(shi)觸點的(de)形式及數量。例如，DL-11/10表(biao)示(shi)電(dian)磁型電(dian)流繼(ji)電(dian)器，其(qi)中第一個(ge)數字"1"表(biao)示(shi)設計(ji)(ji)序(xu)號(hao)(hao)(10系列)，第二個(ge)"1"表(biao)示(shi)有一對動(dong)合觸點，
"10"表示(shi)最大動作電(dian)流(liu)為10A。
4.常用繼電器
35kV及以下電(dian)(dian)(dian)力網中的電(dian)(dian)(dian)力線(xian)路和(he)電(dian)(dian)(dian)氣(qi)設備繼電(dian)(dian)(dian)保護裝置(包括供電(dian)(dian)(dian)系(xi)統)，除了(le)日(ri)漸推廣的微機保護外，仍大量采用電(dian)(dian)(dian)磁型和(he)感(gan)應型繼電(dian)(dian)(dian)器。下面重(zhong)點(dian)介紹幾種反映單一電(dian)(dian)(dian)氣(qi)量的電(dian)(dian)(dian)磁型繼電(dian)(dian)(dian)器的結(jie)構(gou)、原理及特(te)性。
（1）電磁式電流繼(ji)電器
電(dian)磁式(shi)電(dian)流(liu)繼(ji)(ji)電(dian)器在繼(ji)(ji)電(dian)保(bao)護裝置中作為(wei)起動(dong)元件，如(ru)圖(tu)3所(suo)示為(wei)DL系列電(dian)磁式(shi)電(dian)流(liu)繼(ji)(ji)電(dian)器的內部結構和(he)內部接線圖(tu)。
電(dian)磁式電(dian)流(liu)繼電(dian)器的工作原理如(ru)下，當線圈2通過(guo)電(dian)流(liu)IKA時(shi)(shi)(shi)，電(dian)磁力(li)矩M1試圖(tu)使(shi)可動(dong)舌片(pian)(pian)3向順時(shi)(shi)(shi)針方向旋轉。在正常工作時(shi)(shi)(shi)，由(you)于IKA較小，其(qi)所產生的電(dian)磁力(li)矩不(bu)足以(yi)克服(fu)彈簧4的反抗力(li)矩M2，故舌片(pian)(pian)3不(bu)會轉動(dong)，不(bu)會帶動(dong)可動(dong)觸(chu)點(dian)(dian)(dian)5與(yu)(yu)靜觸(chu)點(dian)(dian)(dian)6閉(bi)合；在短路故障時(shi)(shi)(shi)，IKA將(jiang)大(da)大(da)增加，M1>M2，使(shi)舌片(pian)(pian)3轉動(dong)，帶動(dong)可動(dong)觸(chu)點(dian)(dian)(dian)5與(yu)(yu)靜觸(chu)點(dian)(dian)(dian)6接觸(chu)而使(shi)其(qi)閉(bi)合。
能使(shi)過電(dian)(dian)(dian)流(liu)繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)剛好(hao)動(dong)(dong)作(zuo)并(bing)使(shi)觸(chu)點(dian)(dian)閉合的(de)(de)電(dian)(dian)(dian)流(liu)IKA值(zhi)稱(cheng)為(wei)該繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)的(de)(de)動(dong)(dong)作(zuo)電(dian)(dian)(dian)流(liu)，用IOP表示。在繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)動(dong)(dong)作(zuo)后，逐漸減小(xiao)IKA。當繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)剛好(hao)返回到原始位置時(shi)所對(dui)應(ying)的(de)(de)IKA值(zhi)稱(cheng)為(wei)返回電(dian)(dian)(dian)流(liu)，用Ire表示。上(shang)述(shu)定義還可以說成，使(shi)繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)常(chang)開接點(dian)(dian)閉合的(de)(de)最小(xiao)電(dian)(dian)(dian)流(liu)稱(cheng)為(wei)動(dong)(dong)作(zuo)電(dian)(dian)(dian)流(liu)IOP；使(shi)繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)閉合的(de)(de)常(chang)開觸(chu)點(dian)(dian)斷(duan)開的(de)(de)最大(da)電(dian)(dian)(dian)流(liu)稱(cheng)為(wei)返回電(dian)(dian)(dian)流(liu)Ire。繼(ji)(ji)電(dian)(dian)(dian)器(qi)(qi)的(de)(de)返回電(dian)(dian)(dian)流(liu)Ire與(yu)其動(dong)(dong)作(zuo)電(dian)(dian)(dian)流(liu)IOP的(de)(de)比(bi)值(zhi)稱(cheng)為(wei)返回系數Kre(其值(zhi)一般小(xiao)于(yu)1)，即Kre=Ire/IO
（2）電(dian)磁(ci)式電(dian)壓繼電(dian)器
電(dian)(dian)(dian)(dian)磁式電(dian)(dian)(dian)(dian)壓繼電(dian)(dian)(dian)(dian)器(qi)的結(jie)構、工作原理(li)與電(dian)(dian)(dian)(dian)磁式電(dian)(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)(dian)器(qi)基本相同。不同之處是，電(dian)(dian)(dian)(dian)壓繼電(dian)(dian)(dian)(dian)器(qi)的線(xian)(xian)圈(quan)(quan)是電(dian)(dian)(dian)(dian)壓線(xian)(xian)圈(quan)(quan)，其(qi)匝數多而(er)線(xian)(xian)徑細，而(er)電(dian)(dian)(dian)(dian)流(liu)繼電(dian)(dian)(dian)(dian)器(qi)的線(xian)(xian)圈(quan)(quan)為(wei)電(dian)(dian)(dian)(dian)流(liu)線(xian)(xian)圈(quan)(quan)，其(qi)匝數少而(er)線(xian)(xian)徑粗(cu)。
電(dian)磁式電(dian)壓繼(ji)電(dian)器有(you)過電(dian)壓和欠電(dian)壓兩大(da)類，其中欠電(dian)壓繼(ji)電(dian)器在工廠(chang)供電(dian)系統應用較多
類似過電(dian)(dian)流繼電(dian)(dian)器(qi)(qi)，欠電(dian)(dian)壓(ya)(ya)(ya)(ya)繼電(dian)(dian)器(qi)(qi)的動作電(dian)(dian)壓(ya)(ya)(ya)(ya)UOP是(shi)使(shi)其(qi)動作的最(zui)大電(dian)(dian)壓(ya)(ya)(ya)(ya)，而(er)它的返(fan)(fan)回(hui)電(dian)(dian)壓(ya)(ya)(ya)(ya)Ure是(shi)使(shi)其(qi)返(fan)(fan)回(hui)的最(zui)小(xiao)電(dian)(dian)壓(ya)(ya)(ya)(ya)，返(fan)(fan)回(hui)系(xi)數Kre=Ure/UOP。由(you)于(yu)欠電(dian)(dian)壓(ya)(ya)(ya)(ya)繼電(dian)(dian)器(qi)(qi)的返(fan)(fan)回(hui)電(dian)(dian)壓(ya)(ya)(ya)(ya)Ure大于(yu)動作電(dian)(dian)壓(ya)(ya)(ya)(ya)UOP，所以其(qi)返(fan)(fan)回(hui)系(xi)數Kre>1，一般為1~1.2。
（3）電磁式時間繼電器
時間繼電器在保護裝置中起延時作(zuo)(zuo)用，以(yi)保證保護裝置動作(zuo)(zuo)的(de)選擇(ze)性。
DS系列電磁式時間(jian)繼電器(qi)的(de)內部結構(gou)(gou)如(ru)圖4所(suo)示，主(zhu)要由(you)電磁機(ji)構(gou)(gou)和鐘表(biao)(biao)延(yan)時機(ji)構(gou)(gou)兩部分組成(cheng)，電磁機(ji)構(gou)(gou)主(zhu)要起鎖住和釋放鐘表(biao)(biao)延(yan)時機(ji)構(gou)(gou)作用(yong)(yong)，鐘表(biao)(biao)延(yan)時機(ji)構(gou)(gou)起準確(que)延(yan)時作用(yong)(yong)。時間(jian)繼電器(qi)的(de)線圈按(an)短時工作設計。
(4)電磁式
中間繼電(dian)器(qi)的作用是為(wei)了擴充(chong)保(bao)護裝(zhuang)(zhuang)置出口繼電(dian)器(qi)的接點數量和容量，也可以使觸點閉(bi)合(he)或斷開時(shi)(shi)帶有不大(da)的延時(shi)(shi)(0.4~0.8s)，或者通過(guo)繼電(dian)器(qi)的自保(bao)持以適(shi)應(ying)保(bao)護裝(zhuang)(zhuang)置的需要(yao)。
中(zhong)(zhong)間繼電(dian)器(qi)(qi)的工作原理一般按(an)電(dian)磁原理構成，如圖5所示為DZ系列電(dian)磁式中(zhong)(zhong)間繼電(dian)器(qi)(qi)結構圖。
(5)電(dian)磁(ci)式信(xin)號(hao)繼電(dian)器
信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)用(yong)于各保(bao)護裝置回路中，作(zuo)為(wei)保(bao)護動(dong)作(zuo)的(de)指示器(qi)(qi)(qi)。信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)一(yi)般按電(dian)(dian)(dian)(dian)(dian)(dian)磁原理構成(cheng)，繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁起動(dong)機(ji)構采用(yong)吸(xi)引銜鐵式，由直流電(dian)(dian)(dian)(dian)(dian)(dian)源供電(dian)(dian)(dian)(dian)(dian)(dian)。DX系(xi)列信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)結構如圖6所示。在正(zheng)常(chang)(chang)情況下，繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)線圈中沒有電(dian)(dian)(dian)(dian)(dian)(dian)流通過，信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)在正(zheng)常(chang)(chang)位置。當(dang)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)線圈中有電(dian)(dian)(dian)(dian)(dian)(dian)流流過時(shi)，信(xin)號(hao)牌(pai)落(luo)下或(huo)凸出，指示信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)掉牌(pai)。為(wei)了便(bian)于分析故障(zhang)的(de)原因，要求信(xin)號(hao)指示不能隨電(dian)(dian)(dian)(dian)(dian)(dian)氣量的(de)消失而消失。因此(ci)，信(xin)號(hao)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)須設計為(wei)手(shou)動(dong)復歸式。
信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi)可分為(wei)串聯信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi)(電(dian)流(liu)信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi))和并聯信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi)(電(dian)壓信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi))，其接線方(fang)式(shi)如圖7所示。實(shi)際使用時，一般采用電(dian)流(liu)型信(xin)(xin)號(hao)繼(ji)電(dian)器(qi)(qi)。
