電氣專(zhuān)業(yè)畢業(yè)設(shè)計(jì)外文翻譯--變壓器-電氣類(lèi)-資料下載頁(yè)
2025-05-11 20:26本頁(yè)面
【導(dǎo)讀】對(duì)供電電源進(jìn)行電壓等級(jí)變換，應(yīng)對(duì)電能進(jìn)行。重新分配的場(chǎng)所稱(chēng)為變電所。建筑變電所是供配電系統(tǒng)的樞紐，供電電源由電網(wǎng)引到變電所，在。要從遠(yuǎn)端發(fā)電廠送出電能，必須應(yīng)用高壓輸電。變壓器能使電力系統(tǒng)各個(gè)部分運(yùn)行在電壓不同的等級(jí)。原則和電力變壓器的應(yīng)用。變壓器的最簡(jiǎn)單形式包括兩個(gè)磁通相互耦合的固定線圈。兩個(gè)線圈之所以相互耦。它沒(méi)有旋轉(zhuǎn)損失，因此在電壓等級(jí)轉(zhuǎn)換的過(guò)程中，能量損失比較少。從交流電源流入電流的一側(cè)被稱(chēng)為變壓器的一次側(cè)繞組或者是原邊。磁通連接的第二個(gè)繞組被稱(chēng)。磁通是變化的；因此依據(jù)楞次定律，電磁感應(yīng)在。當(dāng)二次側(cè)電路開(kāi)路是，即使原邊被施以正弦電壓Vp，也是沒(méi)有能量轉(zhuǎn)移的。這兩種相關(guān)的損耗被稱(chēng)為鐵芯損耗。應(yīng)注意的是空載電流是畸變和非正弦形的。這種情況是非線性鐵芯材料造成的。電壓Es可以表示出來(lái)。相對(duì)于滿載電流是極其小的。
【正文】 by the “dotmaking” convention. The dots near the upper ends of the windings have the same meaning as in circuit theory。 the marked terminals have the same polarity. Thus when a load is connected to the secondary, the instantaneous load current is in the direction shown. In other words, the polarity markings signify that when positive current enters both windings at the marked terminals, the MMFs of the two windings add. In general, it will be found that the transformer reacts almost instantaneously to keep the resultant core flux essentially constant. Moreover, the core flux φ0 drops very slightly between n o load and full load (about 1 to 3%), a necessary condition if Ep is to fall sufficiently to allow an increase in Ip. On the primary side, Ip’ is the current that flows in the primary to balance the demagizing effect of Is. Its MMF NpIp’ sets up a flux linking the primary only. Since the core flux φ0 remains constant. I0 must be the same current that energizes the transformer at no load. The primary current Ip is therefore the sum of the current Ip’ and I0. Because the noload current is relatively small, it is correct to assume that the primary ampereturns equal the secondary ampereturns, since it is under this condition that the core flux is essentially constant. Thus we will assume that I0 is negligible, as it is only a small ponent of the fullload current. When a current flows in the secondary winding, the resulting MMF (NsIs) creates a separate flux, apart from the flux φ0 produced by I0, which links the secondary winding only. This flux does no link with the primary winding and is therefore not a mutual flux. In addition, the load current that flows through the primary winding creates a flux that links with the primary winding only。 it is called the primary leakage flux. The secondary leakage flux gives rise to an induced voltage that is not counter balanced by an equivalent induced voltage in the primary. Similarly, the voltage induced in the primary is not counterbalanced in the secondary winding. Consequently, these two induced voltages behave like voltage drops, generally called leakage reactance voltage drops. Furthermore, each winding has some resistance, which produces a resistive voltage drop. When taken into account, these additional voltage drops would plete the equivalent circuit diagram of a practical transformer. Note that the magizing branch is shown in this circuit, which for our purposes will be disregarded. This follows our earlier assumption that the noload current is assumed negligible in our calculations. This is further justified in that it is rarely necessary to predict transformer performance to such accuracies. Since the voltage drops are all directly proportional to the load current, it means that at noload conditions there will be no voltage drops in either winding. WonCheol Yun ， Zhong Xiang Zhang Electric power grid interconnection in Northeast Asia Energy Policy 34 (2020) 2298– 2309
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