本文選題：電力變壓器 + 鐵心��； 參考：《華北電力大學(xué)》2017年碩士論文

【摘要】：大型電力變壓器鐵心磁路內(nèi)的剩磁問題是普遍存在的,隨著電力系統(tǒng)的大力發(fā)展,電力變壓器的容量越來越大,電壓等級(jí)越來越高,大型電力變壓器鐵心內(nèi)的剩磁問題也越來越嚴(yán)重,尤其是發(fā)電站的升壓變壓器、用于直流輸電的換流變壓器、變電站的主變,其鐵心剩磁的問題表現(xiàn)的最為嚴(yán)重。剩磁問題具體表現(xiàn)為增大變壓器的空載有功損耗;增大變壓器鐵心的震動(dòng);增大變壓器噪音水平,形成噪音污染;當(dāng)電力變壓器鐵心剩磁非常嚴(yán)重時(shí),對(duì)變壓器的現(xiàn)場(chǎng)空載合閘試驗(yàn)非常不利,造成變壓器空載合閘勵(lì)磁涌流過大,出現(xiàn)繼電器保護(hù)動(dòng)作跳閘現(xiàn)象;跳閘產(chǎn)生的操作沖擊過電壓會(huì)高于變壓器的額定電壓,這可能造成變壓器的絕緣損傷;勵(lì)磁涌流過大會(huì)使得鐵心磁通高度飽和,鐵心出現(xiàn)局部過熱現(xiàn)象,對(duì)鐵心造成損傷;溫度過高會(huì)使絕緣老化加快,變壓器油裂解,從而影響變壓器的運(yùn)行壽命,嚴(yán)重影響了電力系統(tǒng)的安全穩(wěn)定運(yùn)行。因此判斷變壓器鐵心內(nèi)是否有剩磁、如何消除鐵心剩磁已成為人們?nèi)找骊P(guān)注的重點(diǎn)問題。通過分析大型電力變壓器的工作原理、結(jié)構(gòu)特點(diǎn),發(fā)現(xiàn)大型變壓器均為油浸式,其鐵心磁路本身是封閉回路,并且鐵心和繞組完全被變壓器油箱密封屏蔽起來,因此采用常規(guī)的磁場(chǎng)測(cè)量方法不能實(shí)現(xiàn)對(duì)變壓器鐵心內(nèi)的磁場(chǎng)測(cè)量。本文中采用的測(cè)量鐵心磁場(chǎng)的方法是利用繞組本身作為測(cè)量線圈,根據(jù)鐵心的勵(lì)磁曲線的特性(飽和磁通和剩余磁通等特性),通過測(cè)量變壓器繞組首尾兩端電壓,并對(duì)電壓曲線進(jìn)行積分計(jì)算來準(zhǔn)確測(cè)量出鐵心內(nèi)的磁通變化量,準(zhǔn)確計(jì)算出鐵心的最大飽和磁通量、飽和剩磁量和鐵心的初始剩余磁通量;并根據(jù)以上的鐵心磁通測(cè)量方法研究出新型退磁的方法:利用直流電源對(duì)鐵心施加與其剩余磁通量反方向的且等值的磁通量。通過對(duì)不同類型的電力變壓器進(jìn)行退磁,驗(yàn)證了利用此方法去除鐵心剩磁是十分有效的。
[Abstract]:The problem of remanence in the core magnetic circuit of large power transformer is widespread. With the development of power system, the capacity of power transformer becomes larger and larger, and the voltage grade becomes higher and higher. The problem of remanence in the core of large power transformer is more and more serious, especially in the booster transformer of power station, the converter transformer used for DC transmission, the main transformer of substation, the problem of core remanence is the most serious. The problem of remanent magnetism is to increase the no-load active power loss of the transformer; to increase the vibration of the transformer core; to increase the noise level of the transformer; to form noise pollution; when the remanence of the core of the power transformer is very serious, It is very unfavorable to the field no-load closing test of the transformer, which causes the inrush current of the transformer's no-load closing excitation to be too large, the phenomenon of relay protection action tripping occurs, and the operation impulse overvoltage produced by the tripping is higher than the rated voltage of the transformer. This may cause insulation damage to transformers; excessive excitation inrush current causes high saturation of magnetic flux in the core, local overheating of the iron core, and damage to the iron core; excessive temperature will speed up insulation aging and the transformer oil will break up. Therefore, the operation life of transformer is affected, and the safe and stable operation of power system is seriously affected. Therefore, how to determine whether there is remanence in the core of transformer and how to eliminate the remanence of the core has become an increasingly important issue that people pay more and more attention to. By analyzing the working principle and structural characteristics of large power transformers, it is found that the large transformers are oil-immersed, the core magnetic circuit itself is a closed loop, and the core and winding are completely sealed off by the oil tank of the transformer. Therefore, the conventional magnetic field measurement method can not be used to measure the magnetic field in the transformer core. In this paper, the method of measuring the core magnetic field is to use the winding itself as the measuring coil. According to the characteristics of the excitation curve of the core (saturation flux and remanent flux, etc.), the voltage between the two ends of the transformer winding is measured. The integral calculation of the voltage curve is carried out to accurately measure the flux variation in the core and calculate the maximum saturated magnetic flux, saturated remanent magnetic flux and initial residual flux of the core accurately. A new method of demagnetization is developed according to the above methods of core flux measurement: the DC power source is used to apply the equivalent magnetic flux in the opposite direction to the iron core in the direction of its remanent magnetic flux. Through demagnetization of different types of power transformers, it is proved that this method is very effective in removing core remanence.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM41

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 戈文祺;汪友華;陳學(xué)廣;肖樹欣;楊曉光;呂殿利;;電力變壓器鐵心剩磁的測(cè)量與削弱方法[J];電工技術(shù)學(xué)報(bào);2015年16期

2 連杰;;變壓器直流電阻測(cè)試產(chǎn)生的剩磁的影響[J];電力安全技術(shù);2013年11期

3 梁漢城;陳向勝;蘇全;;降低大型變壓器鐵心剩磁的方法和相關(guān)測(cè)試[J];電世界;2013年06期

4 郁光;陳剛;周勇;姜薇;;向家壩水電廠發(fā)變組零起升壓操作淺析[J];水電站機(jī)電技術(shù);2012年05期

5 余克光;;電力變壓器鐵心剩磁檢測(cè)及消除[J];自動(dòng)化應(yīng)用;2012年03期

6 孫飛;田麗華;司秉千;;變壓器剩磁對(duì)發(fā)變組突加電壓保護(hù)的影響及對(duì)策[J];吉林電力;2011年02期

7 儲(chǔ)朝暉;傅正財(cái);;單相變壓器直流偏磁的仿真與試驗(yàn)分析[J];電氣技術(shù);2011年04期

8 陳文臣;劉帆;陳顥;李子湞;;電力變壓器鐵心剩磁檢測(cè)方法研究[J];陜西電力;2009年10期

9 馮遠(yuǎn)程;張浩;鄭龍瑋;;變壓器剩磁對(duì)設(shè)備運(yùn)行的影響與防范[J];上海電力;2009年03期

10 郭滿生;梅桂華;劉東升;劉艷村;程志光;張喜樂;;直流偏磁條件下電力變壓器鐵心B-H曲線及非對(duì)稱勵(lì)磁電流[J];電工技術(shù)學(xué)報(bào);2009年05期

相關(guān)博士學(xué)位論文 前1條

1 姚纓英;大型電力變壓器直流偏磁現(xiàn)象的研究[D];沈陽工業(yè)大學(xué);2000年

相關(guān)碩士學(xué)位論文 前1條

1 高文娟;數(shù)字示波器高級(jí)數(shù)學(xué)運(yùn)算功能設(shè)計(jì)[D];電子科技大學(xué);2013年

，

本文編號(hào)：2099659