本文選題：換流變壓器 + 直流偏磁　； 參考：《沈陽(yáng)工業(yè)大學(xué)》2017年碩士論文

【摘要】：近些年來(lái),我國(guó)高壓直流輸電工程的發(fā)展達(dá)到了前所未有的高度,為了滿足直流輸電的發(fā)展需要,作為高壓直流輸電系統(tǒng)重要設(shè)備的換流變壓器也得到了越來(lái)越多的研究。直流電網(wǎng)和地磁暴等因素引起的直流偏磁現(xiàn)象逐漸增多,加上高壓直流輸電有較大高次諧波的特點(diǎn),所以在運(yùn)行中的換流變壓器必然承受著直流偏磁和諧波對(duì)其的影響。發(fā)生直流偏磁的情況時(shí),換流變壓器將會(huì)出現(xiàn)勵(lì)磁電流波形的嚴(yán)重畸變,而發(fā)生偏磁的電流越大則越容易出現(xiàn)半周期嚴(yán)重飽和的尖頂波電流波形。尖頂波的出現(xiàn)將使得換流變壓器的漏磁增大,由漏磁引起的損耗必然增加,進(jìn)而引起變壓器的局部過(guò)熱。高壓直流輸電中的負(fù)載電流中含有大量的高次諧波分量,諧波分量必然將產(chǎn)生與其對(duì)應(yīng)的漏磁場(chǎng)和損耗�；ㄅc高次諧波產(chǎn)生的損耗將共同作用于換流變壓器的結(jié)構(gòu)件上,損耗的分布一般不是均勻分布的而是集中在結(jié)構(gòu)件的某個(gè)區(qū)域上,損耗過(guò)大將很可能引起變壓器的某一區(qū)域的局部過(guò)熱,進(jìn)而將影響到換流變壓器的正常運(yùn)行狀態(tài)。換流變壓器的局部過(guò)熱又將引起絕緣的老化影響其使用壽命,所以本文對(duì)換流變壓器出現(xiàn)這兩種特殊情況下的溫升進(jìn)行了仿真計(jì)算。本文的主要工作有以下兩點(diǎn):第一,采用實(shí)驗(yàn)的方式對(duì)換流變壓器的鐵心硅鋼片在直流偏磁以及諧波的條件下進(jìn)行了磁特性的測(cè)量。第二,基于有限元仿真原理對(duì)不同直流偏磁及5次、7次諧波條件下的一臺(tái)實(shí)際的換流變壓器溫度進(jìn)行了計(jì)算。對(duì)比分析了兩種情形下的溫度場(chǎng)分布情況:(1)分別使用正常磁特性曲線與直流偏磁磁特性曲線下的溫度場(chǎng)仿真分布情況;(2)分別使用正常磁特性曲線與使用諧波磁特性曲線下的溫度場(chǎng)仿真分布情況。仿真分析了4mm厚的銅屏蔽對(duì)于直流偏磁和諧波條件下漏磁場(chǎng)增大引起的溫度升高的抑制作用。從仿真結(jié)果來(lái)看,換流變壓器在發(fā)生較大直流偏磁以及承受高次諧波時(shí)將會(huì)出現(xiàn)局部過(guò)熱現(xiàn)象,而這種現(xiàn)象必將會(huì)嚴(yán)重影響其使用壽命。本文對(duì)直流偏磁和諧波條件下的換流變壓器溫升進(jìn)行的計(jì)算,為換流變壓器溫升問(wèn)題的進(jìn)一步研究奠定基礎(chǔ)。
[Abstract]:In recent years, the development of HVDC power transmission project in China has reached an unprecedented height. In order to meet the needs of the development of HVDC transmission, the converter transformer, which is an important equipment for HVDC transmission system, has also been more and more studied. The phenomenon of DC bias caused by DC power grid and geomagnetic storms is increasing gradually, and higher The HVDC power transmission has the characteristics of higher harmonics, so the converter transformer in operation is bound to bear the influence of DC bias and harmonic wave on it. When the DC bias magnetic field occurs, the converter transformer will have serious distortion of the excitation current waveform, and the larger the magnetic current is, the more likely it will be half cycle and serious saturation. The emergence of the spike wave will increase the flux leakage of the converter transformer. The loss caused by magnetic flux leakage will inevitably increase and cause the local overheating of the transformer. The load current in HVDC transmission contains a large number of high order harmonic components, and the harmonic components will inevitably produce its corresponding leakage magnetic field and loss. The loss caused by high order harmonics will work together on the structure parts of the converter transformer. The loss distribution is generally not uniformly distributed but concentrated in some region of the structural parts. Excessive loss will probably cause local overheating in a certain area of the transformer, and will affect the normal running state of the converter transformer. The partial overheating of the device will cause the aging of the insulation to affect its service life, so this paper has simulated the temperature rise of the converter transformer under these two special circumstances. The main work of this paper is the following two points: first, the iron core silicon steel sheet of the converter transformer is under the condition of DC bias and harmonic. The measurement of magnetic properties is carried out. Second, based on the finite element simulation principle, the temperature of a practical converter transformer under different DC bias and 5 times and 7 harmonic conditions is calculated. The temperature field distribution in two cases is compared and analyzed. (1) the temperature under the normal magnetic characteristic curve and the DC bias magnetic characteristic curve are used respectively. The distribution of field simulation, (2) the simulation distribution of the temperature field under the normal magnetic characteristic curve and the harmonic magnetic characteristic curve is used respectively. The simulation and analysis of the inhibition effect of the 4mm thick copper shielding on the increase of the temperature caused by the leakage magnetic field increases under the condition of direct current bias and magnetic resonance. In this paper, the calculation of the temperature rise of the converter transformer under the condition of DC bias and harmonic wave will lay a foundation for the further research on the temperature rise of the converter transformer.

【學(xué)位授予單位】：沈陽(yáng)工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM721.1;TM41

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 蘇小平;陳偉根;胡啟元;陳W，

本文編號(hào)：1812807