0241-某精細(xì)化工廠高配所及全廠配電系統(tǒng)設(shè)計(jì)【全套8張CAD圖】

0241-某精細(xì)化工廠高配所及全廠配電系統(tǒng)設(shè)計(jì)【全套8張CAD圖】,全套8張CAD圖,精細(xì),化工廠,所及,全廠,配電,系統(tǒng),設(shè)計(jì),全套,cad 翻譯文獻(xiàn)（英譯中） 原文: Fault—clearing Protective Relays(1) ??? Overcurrent relaying．Slow—speed relays．The most obvious effect of a fault is to change the current in the faulted conductor from a normal value to an abnormally large one．Therefore it is not surprising that the earliest methods of clearing faults were based on the utilization of that effect(overcurrent)．Early methods included fuses，circuit breakers with ?series trip coils，and slow—speed overcurrent relays． ??? ??? Slow—speed overcurrent relays are mostly of the induction type．To obtain selectivity without unnecessarily long delay，such relays usually have a delay which varies inversely with the current．Both time and current settings are adjustable．Since the fault current decreases，on account of the increased impedance of the line between the fault and the source． as the fault is mo，ved farther from the source of power，it follows that the relay operating time increases as the distance to the fault increases. ??? ???? The time—distance curves change with such conditions as connected generating capacity and the connection or disconnection of other transmission lines，and therefore，to ensure selectivity，curves should be checked for several conditions to ascertain that．under the worst condition，an adequate interval exists between the operating times of relays 1 and 3，and, similarly，between each pair of relays on adjoining line sections．Coordination may be accomplished by judicious choice of both time settings and current settings． ??? ???? If the relay current changes but little with fault location，the curve of relay time versus fault position becomes more like curve a than ike curve b．Such a condition is likely to exist if the impedance of the protected section is small compared with the impedance between the generators and the protected section，as may well be true if the section is short and is fed ?solely or principally from one end．Moreover curve a may hold even though the relay current does change with fault location，if，as is usually true，the relays are operating on the minimum-time part of their time—current characteristic．Curve a represents an undesirable condition when several protected line sections are in cascade，because the relay time of the lines ?near the source of power becomes increasingly long． ??? ???? If a line section is long or has power sources at each end，the relay current will vary considerably with fault location．But，even if the current varies enough to give a curve like b，the operating time of a relay near the generator is usually somewhat longer than that of a relay farther from the generator，though not so much longer as in curve a． ??? ???? By the use of graded time settings，overcurrent relays can always be made to work selectively on a radial transmission or distribution system．With graded settings，and with the addition of directional relays，overcurrent relays can be made to work selectively on a loop system fed from one point．But on a loop fed sometimes from one point and sometimes from another，or on a network more complex than a loop，it is difficuh，if not impossible，to choose settings for overcurrent relays so that the relays will work selectively for all fault locations and for all operating conditions． ? 譯文: 故障切除繼電保護(hù)裝置(1) ??? 現(xiàn)在來(lái)談?wù)勥^(guò)電流繼電保護(hù)裝置，特別是延時(shí)過(guò)電流繼電保護(hù)裝置。故障出現(xiàn)時(shí)，最明顯的變化是故障導(dǎo)體中的電流由正常的電流值變?yōu)榉钦５拇箅娏鳌Ｒ虼?，故障切除所采用的早期方法就是以電流的變化為依?jù)。早期所使用的手段包括熔絲、串聯(lián)跳閘線圈斷路器和延時(shí)過(guò)電流繼電器。 ??? ?? 延時(shí)過(guò)電流繼電器大都是感應(yīng)型，為了滿足選擇性和速動(dòng)性，這種繼電保護(hù)器通常具有反時(shí)限特性。時(shí)間和電流整定都具有可調(diào)性，由于故障電流較小，當(dāng)故障離電源較遠(yuǎn)時(shí)，考慮到故障與電源之間線路的阻抗較大，繼電器的動(dòng)作時(shí)間會(huì)隨著故障距離的增加而延長(zhǎng)。 ??? ?? 時(shí)間與距離曲線是依據(jù)連接的發(fā)電容量與以其它線路連接或中斷的狀態(tài)而變化的。因此，為確保選擇性應(yīng)校驗(yàn)曲線，保證在嚴(yán)重的狀態(tài)下，繼電器#1和#3動(dòng)作時(shí)間之間有適當(dāng)?shù)臅r(shí)間間隔。在相鄰的線路上每一對(duì)繼電器之間也同樣要有時(shí)間間隔，這種配合通過(guò)恰當(dāng)選擇時(shí)間與電流的整定值來(lái)完成。 ??? ?? 假如繼電器中的電流由于故障而改變，但變化不大，那么故障點(diǎn)對(duì)應(yīng)的時(shí)間的曲線變化與a曲線更相像。假如被保護(hù)線路的阻抗與發(fā)電機(jī)和保護(hù)線路之間的阻抗相比較小時(shí)，就能呈現(xiàn)與a曲線相似的這樣一種狀態(tài)。如線路較短，又是單電源供電或主要從一端供電，情況也是如此。此外，即使繼電器中的電流隨故障點(diǎn)變動(dòng)而改變，a曲線仍可能保持不變。如果繼電器進(jìn)行瞬時(shí)動(dòng)作，通常情況也是如此。當(dāng)幾條被保護(hù)線路進(jìn)行串聯(lián)時(shí)，a曲呈現(xiàn)著不理想的狀態(tài)，因?yàn)榭拷娫吹木€路繼電器動(dòng)作時(shí)間相應(yīng)變長(zhǎng)。 ??? ??? 如果一條線路較長(zhǎng)或每一端都有電源，繼電器的電流就會(huì)隨故障點(diǎn)的不同將作相應(yīng)的改變。但即使電流的改變足以像b曲線，靠近發(fā)電機(jī)的繼電器動(dòng)作時(shí)間也比距發(fā)電機(jī)較遠(yuǎn)的繼電器動(dòng)作時(shí)間長(zhǎng)，但不如a曲線的時(shí)間長(zhǎng)。 ??? ??? 通過(guò)采用階段時(shí)間配置，過(guò)電流繼電保護(hù)裝置能在輸電系統(tǒng)或配電系統(tǒng)中有選擇性地工作，使用階段配置并利用方向性繼電器，過(guò)電流繼電器從單電源供電系統(tǒng)中有選擇性地工作，但在單回線從一端或從另一端供電的線路中，或在一個(gè)比一條線路更復(fù)雜的網(wǎng)絡(luò)中，要想使這種繼電裝置對(duì)一切故障和動(dòng)作狀態(tài)進(jìn)行選擇性工作，對(duì)過(guò)電流繼電裝置的整定值的確定，將不是一件容易的事 原文： Fault—clearing Protective Relays(2) ??? High—speed relays．It has already been noted that the relay current during a fault usual． 1y decreases as the distance to the fault location increases．When this location is exactlv at ?the far end of the protected section，the relay current has fl certain value，and，provided that ?other conditions are constant，fl relay current exceeding this value is fl certain indication of a ?fault in the protected section——a condition for which the circuit breaker should be tripped． Tripping may be accomplished under these conditions by the use of fl high—speed overcurrent ?relay having a pick-up current equal to the current produced by fl fault at the distant end of ?the section．In practice，the balance point of the relay·(that is，the fault location that will ?just make the relay pick up)must be somewhat closer than the distant end，for reasons a1一 ready discussed．The contacts of the high—speed relay are connected in parallel with the con— tacts of a slow-speed overcurrent relay so that。either relay can trip the circuit breaker．FauIts ?closer to the relay location than the balance point of the high—speed relay are cleared by this ?relay．Clearing of faults farther away(that is，in the end zone)and back—up protection of the ?next section are accomplished by the slow—speed relay． ??? The chief weakness of high—speed overcurrent relaying is that the balance point varies ?with the type of fault and with conditions outside the protected section，such as the connect— ed generating capacity and the opening or closing of other transmission lines．For example。a three—phase fault usually results in greater fault current than a line—to：line fauIt at the same ?place．Hence，in order to produce equal currents in an overcurrent relay，the three-phase fault must be farther from the relay than the line-to—line fault．In other words，the balance ?point for a three—phase fault is farther from the relay than is the balance point for a line-to— line fault．Again，the additional generating capacity，or the closing of an additional transmis— sion line，may decreasfi the impedance between the sources of power and the fauIt position． thereby increasing the fault current for a given type and location of fault，or，in other words， shifting the balance point farther away from the relay．To assure selective relay action。the ?balance point must never be permitted to move OUt of the protected section under the most ?severe fault conditions．If the high—speed overcurrent relay is set so that this danger is avoid— ed，then the balance point must shift and cover fl considerable distance towards the relav un- der less severe fault conditions，giving a long end zone，in which faults are cleared with de— lay，and a short——perhaps Vanishing——zone in which fauIts are cleared rapidly．It is ap— parent that high—speed overcurrent relays can not be depended upon to clear faults consistent— ly over a large portion of the line unless external conditions are fairly constant．Neverthe— less，the addition of a high～speed overcurrent relay to an existing slow—speed overcurrent re— lay installation will effect more or less improvement in the average speed of clearing faults． ? 譯文： 故障切除繼電保護(hù)裝置（2） 瞬時(shí)電流速斷保護(hù)：繼電器中的電流隨著故障點(diǎn)離保護(hù)裝置外的距離的增加而減小，當(dāng)故障恰好發(fā)生在速斷保護(hù)區(qū)末端時(shí)，繼電器的整定值固定。假設(shè)其他條件不變，如果流過(guò)繼電器的電流超過(guò)這個(gè)整定值，那就表明故障一定在本保護(hù)區(qū)內(nèi)，斷路器應(yīng)跳閘。跳閘動(dòng)作時(shí)通過(guò)瞬時(shí)電流速斷實(shí)現(xiàn)的，即繼電器的整定值與被保護(hù)線路末端的故障電流要相等。實(shí)際上，繼電保護(hù)的動(dòng)作邊界(使繼電器恰好動(dòng)作的故障點(diǎn))必須比末端距離近些。詳細(xì)的原由已作過(guò)論述。瞬時(shí)保護(hù)裝置的觸點(diǎn)是與延時(shí)保護(hù)裝置的觸點(diǎn)并聯(lián)的，為的是任何一段保護(hù)動(dòng)作都能使斷路器跳閘。當(dāng)故障在瞬時(shí)電流速斷保護(hù)區(qū)內(nèi)時(shí)，該故障由瞬時(shí)速斷保護(hù)切除，而對(duì)于遠(yuǎn)距離故障的切除(即末端線路上)和對(duì)下一段線路的后備保護(hù)則是由延時(shí)保護(hù)完成的。 ??? 瞬時(shí)過(guò)電流保護(hù)器的主要缺點(diǎn)，在于動(dòng)作邊界隨故障類型和被保護(hù)線路以外的各種條件 的變化而改變。諸如：機(jī)組并列增加發(fā)電容量和其它輸電線路的打開(kāi)與閉合。例如，三相電故障比在同一地點(diǎn)的相間故障通常導(dǎo)致更大的故障電流。因此，為了使過(guò)電流器中的電流相等，三相故障點(diǎn)必須比相間線路故障點(diǎn)距繼電器的位置要遠(yuǎn)。也就是，三相故障的動(dòng)作邊界比相間故障的動(dòng)作邊界離繼電器遠(yuǎn)。另一方面，增加發(fā)電容量或關(guān)閉附加輸電線路會(huì)減少電源與故障點(diǎn)間的阻抗，因而在給定故障類型和故障點(diǎn)的情況下，增大故障電流。換句話說(shuō)，讓動(dòng)作邊界離繼電器更遠(yuǎn)。為獲得繼電器保護(hù)的選擇性，動(dòng)作邊界在最嚴(yán)重的故障狀態(tài)中進(jìn)行整定，決不允許超出被保護(hù)線路以外。如果安裝瞬時(shí)速斷保護(hù)，這種情況就可以避免(動(dòng)作邊界超出被保護(hù)線路之外)。故障不嚴(yán)重，動(dòng)作邊界相應(yīng)地縮小。在末端很長(zhǎng)范圍內(nèi)的故障要由延時(shí)保護(hù)器切除．在短的(或許已有消失的)范圍內(nèi)，故障可被迅速切除。除非外部條件相當(dāng)穩(wěn)定，顯然不能完全依靠瞬時(shí)過(guò)電流保護(hù)器連續(xù)大范圍地進(jìn)行故障切除。然而，在延時(shí)過(guò)電流繼電器上裝配瞬時(shí)過(guò)電流繼電器將會(huì)相應(yīng)提高故障切除速度。