110kv變電所設(shè)計外文翻譯-其他專業(yè)-資料下載頁
2025-01-19 06:32本頁面
【導(dǎo)讀】XF110KV變電所是地區(qū)重要變電所，是電力系統(tǒng)110KV電壓等級的重要部分?？傮w分析;負荷分析與主變選擇;電氣主接線設(shè)計;短路電流計算;電氣設(shè)備選擇;配電裝置選擇;變電所總平設(shè)計及防雷保護設(shè)計。二次部分由說明書，計算書與電氣工程圖組成。說明書和計算書包括整體概。其中一次部分電氣AutoCAD制圖六張；二。次部分為四張手工制圖。本變電所設(shè)計為畢業(yè)設(shè)計課題，以鞏固大學所學知識。題的能力，為未來的實際工作奠定了必要的基礎(chǔ)。在此要對老師們不辭勞苦的工作和無私奉獻的精神表示衷。設(shè)計中雖然充分采納了老師和同學們的意見，幾經(jīng)修改，但由于是初次設(shè)計，高電壓必須降低。們討論的原則和電力變壓器的應(yīng)用。為它沒有旋轉(zhuǎn)損失，因此在電壓等級轉(zhuǎn)換的過程中，能量損失比較少。率范圍在92到99%，上限值適用于大功率變壓器。組被稱為變壓器的二次側(cè)繞組或者是副邊。磁通是變化的；因此依據(jù)楞次定律，這兩種相關(guān)的損耗被稱為鐵。第二個分量Ie=I0sinθ0，與原邊電壓同相。
【正文】 Since the secondary voltage depends on the core flux φ0, it must be clear that the flux should not change appreciably if Es is to remain essentially constant under normal loading conditions. With the load connected, a current Is will flow in the secondary circuit, because the induced EMF Es will act as a voltage source. The secondary current produces an MMF NsIs that creates a flux. This flux has such a direction that at any instant in time it opposes the main flux that created it in the first place. Of course, this is Lenz’s law in action. Thus the MMF represented by NsIs tends to reduce the core flux φ0. This means that the flux linking the primary winding reduces and consequently the primary induced voltage Ep, This reduction in induced voltage causes a greater difference between the impressed voltage and the counter induced EMF, thereby XXX： XF110KV 變電所設(shè)計 11 allowing more current to flow in the primary. The fact that primary current Ip increases means that the two conditions stated earlier are fulfilled: (1) the power input increases to match the power output, and (2) the primary MMF increases to offset the tendency of the secondary MMF to reduce the flux. 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.
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