【正文】 常和事故情況下的供送電情況。折舊費(fèi)及大修費(fèi)，日常小修費(fèi)等維護(hù)費(fèi)。6) 6～10kV固定式配電裝置的出線側(cè)，在架空線路或有反饋可能的電纜出線回路中，應(yīng)裝設(shè)線路隔離開(kāi)關(guān)。這種主接線圖兼有內(nèi)外橋式接線的運(yùn)行靈活性的優(yōu)點(diǎn)，但所用高壓開(kāi)關(guān)設(shè)備較多，可供一、二級(jí)負(fù)荷，適用于一、二次側(cè)進(jìn)出線較多的總降壓變電所分段的單母線與不分段的相比較，提高了接線的可靠性和靈活性。這種外橋式適用于電源線路較短而變電所負(fù)荷變動(dòng)較大、適用經(jīng)濟(jì)運(yùn)行需經(jīng)常切換的總降壓變電所。計(jì)算負(fù)荷是一個(gè)假想的持續(xù)性的負(fù)荷，其熱效應(yīng)與同一時(shí)間內(nèi)實(shí)際變動(dòng)負(fù)荷所產(chǎn)生的最大熱效應(yīng)相等。 負(fù)荷計(jì)算的方法負(fù)荷計(jì)算的方法有需要系數(shù)法、利用系數(shù)法及二項(xiàng)式法等幾種。但由于國(guó)內(nèi)對(duì)利用系數(shù)缺乏切實(shí)的工作和數(shù)據(jù)的積累，計(jì)算方法本身也較上述兩種方法復(fù)雜，故尚未得到廣泛采用。3)在設(shè)計(jì)屋外高壓配電裝置時(shí)，需按短路條件校驗(yàn)軟導(dǎo)線相間和相對(duì)地安全距離。在等效電路圖上，只需將被計(jì)算的短路電流所流經(jīng)的一些主要元件表示出來(lái)，并標(biāo)明其序號(hào)和阻抗值，然后將等效電路化簡(jiǎn)。① 變壓器的外部故障常見(jiàn)的是高低壓套管及引線故障，它可能引起變壓器出線端的相間短路或引出線碰接外殼。2) 后備保護(hù)：過(guò)電流保護(hù)（以反應(yīng)變壓器外部相間故障）、過(guò)負(fù)荷保護(hù)（反應(yīng)由于過(guò)負(fù)荷而引起的過(guò)電流）。但實(shí)際上由于變壓器的勵(lì)磁涌流、接線方式及電流互感器誤差等因素的影響，繼電器中存在不平衡電流，變壓器差動(dòng)保護(hù)需解決這些問(wèn)題，方法有：①靠整定值躲過(guò)不平衡電流②采用比例制動(dòng)差動(dòng)保護(hù)。A及以上和并列運(yùn)行的變壓器每臺(tái)容量在6300kV后備保護(hù)不僅可以起到當(dāng)主保護(hù)應(yīng)該動(dòng)作而未動(dòng)作時(shí)的后備，還可以起到當(dāng)主保護(hù)雖已動(dòng)作但最終未能達(dá)到切除故障部分的作用。瓦斯保護(hù)動(dòng)作于跳閘的重瓦斯部分，通常按氣體繼電器的油流速度整定。由于35 kV側(cè)二次電流大，因此以35kV側(cè)為基本側(cè)。代入數(shù)據(jù)得： （） 比較上述（）（）（）式的動(dòng)作電流，取最大值為計(jì)算值， 即： 將兩側(cè)電流互感器分別接于繼電器的兩組平衡線圈，再接入差動(dòng)線圈，使繼電器的實(shí)用匝數(shù)和動(dòng)作電流更接近于計(jì)算值；以二次回路額定電流最大側(cè)作為基本側(cè)，基本側(cè)的繼電器動(dòng)作電流及線圈匝數(shù)計(jì)算如下：基本側(cè)（35kV）繼電器動(dòng)作值 （）代入數(shù)據(jù)得： （）基本側(cè)繼電器差動(dòng)線圈匝數(shù) （）式中：Awo為繼電器動(dòng)作安匝，應(yīng)采用實(shí)際值，本設(shè)計(jì)中采用額定值，取得60安匝。2） 靈敏度按保護(hù)范圍末端短路進(jìn)行校驗(yàn)。 對(duì) 3～10kV 線路裝設(shè)相間短路保護(hù)裝置，應(yīng)符合下列要求： 1) 由電流繼電器構(gòu)成的保護(hù)裝置，應(yīng)接于兩相電流互感器上，同一網(wǎng)絡(luò)的所有線路均應(yīng)裝在相同的兩相上； 2) 后備保護(hù)應(yīng)采用遠(yuǎn)后備方式；3) 當(dāng)線路短路使發(fā)電廠廠用母線或重要用戶母線電壓低于額定電壓的60%時(shí)，以及線 路導(dǎo)線截面過(guò)小,不允許帶時(shí)限切除短路時(shí)，應(yīng)快速切除故障；4) 電流保護(hù)的時(shí)限不大于 ～ 時(shí)，且沒(méi)有第三款所列的情況，或沒(méi)有配合上 的要求時(shí)，可不裝設(shè)瞬動(dòng)的電流速斷保護(hù)。 對(duì) 35～63kV 線路，可按下列要求裝設(shè)相間短路保護(hù)裝置：1) 對(duì)單側(cè)電源線路可采用一段或兩段電流速斷或電流閉鎖電壓速斷作主保護(hù)，并應(yīng)以帶時(shí)限過(guò)電流保護(hù)作后備保護(hù)。2) 10kV線路過(guò)電流保護(hù):是利用短路時(shí)的電流比正常運(yùn)行時(shí)大的特征來(lái)鑒別線路發(fā)生了短路故障，其動(dòng)作的選擇性由過(guò)電流保護(hù)裝置的動(dòng)作具有適當(dāng)?shù)难訒r(shí)來(lái)保證，有定時(shí)限過(guò)電流保護(hù)和反時(shí)限過(guò)電流保護(hù)；本設(shè)計(jì)與電流速斷保護(hù)裝置共用兩組電流互感器，采用二相二繼電器的不完全星形接線方式，選用定時(shí)限過(guò)電流保護(hù)，作為電流速斷保護(hù)的后備保護(hù)，來(lái)切除電流速斷保護(hù)范圍以外的故障，其保護(hù)范圍為本線路全部和下段線路的一部分。3) 第一段的靈敏性通常用保護(hù)范圍的大小來(lái)衡量，根據(jù)本設(shè)計(jì)的數(shù)據(jù)，按線路首端（d1點(diǎn)）短路時(shí)的最小短路電流校驗(yàn)靈敏系數(shù)。作為本線路后備保護(hù)時(shí)的靈敏系數(shù)為： （）靈敏系數(shù)滿足要求。② 煉鐵廠、配電所：1) 躲配變低壓側(cè)母線最大三相短路電流，具體做法是選擇一個(gè)最大容量配變，如有多個(gè)最大容量配變則選擇距出線斷路器最近者。其中：；2) 保護(hù)的動(dòng)作時(shí)限t2應(yīng)與t1配合，即： （），故選用DS111型時(shí)間繼電器，～ s。這次畢業(yè)設(shè)計(jì)由于資料不夠，所以我們多人一組共享資源，這無(wú)意是對(duì)我們的相互協(xié)作能力的考驗(yàn)，在遇到一個(gè)人不能解決的問(wèn)題時(shí)，我們共同商量，找到解決的方法。同時(shí)，也感謝在此次畢業(yè)設(shè)計(jì)中給予我?guī)椭乃腥恕?hence transformer equipment is included.Sectionalizing.─In very long highvoltage large capacity lines, particularly when several circuits are run in parallel, it is often necessary to split the lines into sections, in order that proper protection to the line and service can be obtained. Such a substation is , therefore, helpful in sectionalizing damaged sections of a line, providing continuity of service. Such a substation will generally prise only switching equipment. In long lines it may also serve to supply powerfactorcorrecting equipment.Transmissionline Supply.─It is being more and more mon to install the hightension equipment of a power plant outdoors, the installation being nothing more than a stepup substation receiving its power at generator voltage, then stepping up its voltage and finally sending it out over highvoltage transmission lines. Such a substation is nothing more than an outdoor distributing substation turned around, the voltage being stepped up instead of stepped down.Powerfactor Correction.─The voltage at the end of long lines tends to increase as the load supplied is decreased, while on the other hand it tends to decrease as the load is increased. Owing to the inductance and capacity effects, this variation in voltage is acpanied by a wide variation in power factor of a line, it is necessary to use synchronous condensers at the end of the line. To supply such a machine the transmissionline voltage must be stepped down, hence a powerfactorcorrecting substation will include switching equipment, transformers, and all equipment necessary for the operation of synchronous condensers.Railway.─Substations supplying railways may be generally classified under two heads, namely, as alternating current and as direct current. In the cases of alternatingcurrent substations the problem is generally one of voltage transformation and of supplying singlephase power to the trains. It is, however, possible to supply singlephase to threephase inside the lootive by the use of a phase converter. In the case of directcurrent railways, the substations are generally supplied whit threephase power and converted to direct current by means of rotary converters, motorgenerator sets, or rectifiers.Direct current for Light and Power.─There are still a few sections in some of out large cities, which are supplied with directcurrent threewire systems. Such a supply is invariably obtained from synchronous converters. There are also certain types of motor loads in industrial plants, which require direct current.Because many cities have experience rapid growth, their substations have often reached the limits of their capacity. As a result, downtown distribution systems are often overworked and many need a major, overhaul, overhaul, or expansion. However, space is scarce. Downtown business owners do not want “ugly” new substation marring the area’s appearance, but nor do businesses and residents grid the prospect of grid disturbances.One example of a system capable of integrating equipment monitoring with substation automation is the GE Harris integrated Substation Control System (ISCS). The system can integrate data from both substation system and equipment online monitoring devices into a mon data base. The data can then be processed by an expert system into information on the status and health of monitored equipment using selfdiagnostic programs. This information is then sent to a CMMS for automatic generation and tracking of maintenance work orders leads directly to the significant efficiencies found with conditionbased maintenance programs.ABB Power and its industry partners have bined to develop the ABB Power System software. The system contains a diagnostic and maintenance system that reports necessary maintenance before failure. It allows utilities and industrial