【摘要】：在高壓直流輸電系統(tǒng)中,換流站本身的工作性質(zhì)導(dǎo)致?lián)Q流變壓器中存在大量的諧波及直流偏磁現(xiàn)象。諧波將引起換流變壓器損耗增加、電氣絕緣破壞及局部過(guò)熱等問(wèn)題;同時(shí),直流偏磁將對(duì)換流變壓器的正常運(yùn)行帶來(lái)一系列危害,如勵(lì)磁電流發(fā)生畸變、諧波及損耗增加、振動(dòng)及噪聲加劇、鐵心綁帶松脫、鐵心柱彎曲、鐵心片串片等,因此在產(chǎn)品設(shè)計(jì)過(guò)程中準(zhǔn)確分析計(jì)算直流偏磁及諧波影響下?lián)Q流變壓器的損耗問(wèn)題,對(duì)降低系統(tǒng)諧波及損耗、提高換流變壓器穩(wěn)定性具有重要的意義。由于不同激勵(lì)對(duì)電工鋼片磁特性影響不同,準(zhǔn)確分析換流變壓器的電磁性能離不開(kāi)對(duì)電工鋼片磁特性的準(zhǔn)確描述,因此本文測(cè)量分析了直流偏置激勵(lì)、非正弦激勵(lì)及不同溫度條件下電工鋼片的磁特性,并將測(cè)得的數(shù)據(jù)應(yīng)用到換流變壓器相應(yīng)運(yùn)行狀態(tài)的損耗計(jì)算中,對(duì)比分析了電工鋼片磁特性的變化對(duì)計(jì)算直流偏磁及諧波條件下?lián)Q流變壓器磁場(chǎng)及損耗的影響,具體工作內(nèi)容如下:首先,本文介紹了電工鋼片磁特性測(cè)量的方法,基于德國(guó)進(jìn)口的磁特性測(cè)量系統(tǒng),測(cè)量了不同溫度的交流磁場(chǎng)、交直流磁場(chǎng)以及諧波磁場(chǎng)作用下硅鋼片的磁特性和諧波磁場(chǎng)作用下油箱所用材料Q235B鋼的磁特性,包括B-H曲線、B-P曲線以及磁滯回線。進(jìn)而具體分析了溫度變化、直流偏磁電流變化、諧波次數(shù)變化及諧波含量變化對(duì)電工鋼片磁特性的影響。其次,根據(jù)特變電工股份有限公司提供的產(chǎn)品級(jí)模型數(shù)據(jù),運(yùn)用MagNet有限元軟件建立了該換流變壓器的三維主磁場(chǎng)仿真模型。為了研究硅鋼片磁特性變化對(duì)不同直流偏磁工作狀態(tài)的換流變壓器主磁場(chǎng)及鐵心損耗的影響,基于本文第二章所測(cè)得的硅鋼片磁特性數(shù)據(jù),本部分采用場(chǎng)路耦合的方法在瞬態(tài)場(chǎng)中考慮了無(wú)直流偏磁室溫(20℃)條件下與不同直流偏磁工作溫度(80℃)條件下硅鋼片的磁特性。最終將上述結(jié)果與試驗(yàn)值進(jìn)行了對(duì)比,證明了本文所提出改進(jìn)計(jì)算方法的可靠性。最后,根據(jù)特變電工股份有限公司提供的產(chǎn)品級(jí)模型數(shù)據(jù),運(yùn)用MagNet有限元軟件建立了該換流變壓器的三維漏磁場(chǎng)仿真模型。為了研究硅鋼片、Q235B鋼磁特性變化對(duì)諧波作用下?lián)Q流變壓器漏磁場(chǎng)及結(jié)構(gòu)件雜散損耗的影響,基于本文第二章所測(cè)得的電工鋼片磁特性數(shù)據(jù),本部分采用場(chǎng)路耦合的方法在瞬態(tài)場(chǎng)中考慮了無(wú)諧波工作溫度(80℃)條件下和含有諧波工作溫度(80℃)條件下硅鋼片、Q235B鋼磁特性。然后運(yùn)用IEC 61378-2標(biāo)準(zhǔn)計(jì)算了諧波條件下?lián)Q流變壓器的結(jié)構(gòu)件雜散損耗,并給出了以上方法計(jì)算結(jié)果與試驗(yàn)值的對(duì)比,驗(yàn)證了本文研究方法的可靠性。
[Abstract]:In HVDC transmission system, the nature of converter station itself leads to a large number of harmonic and DC bias phenomena in converter transformer. At the same time, DC bias will bring a series of harm to the normal operation of converter transformer, such as the distortion of excitation current, the increase of harmonic and loss. In the process of product design, the loss of converter transformer under the influence of DC bias magnetic field and harmonic wave is accurately analyzed and calculated, which can reduce the harmonic and loss of the system. It is very important to improve the stability of converter transformer. Because different excitations have different effects on the magnetic properties of electrical steel sheet, the accurate analysis of electromagnetic properties of converter transformers is inseparable from the accurate description of magnetic characteristics of electrical steel sheets, so the DC bias excitation is measured and analyzed in this paper. The magnetic properties of electrical steel sheet under non-sinusoidal excitation and different temperatures are applied to the calculation of the loss of converter transformer in corresponding operation state. The effect of magnetic characteristics of electrical steel sheet on the calculation of magnetic field and loss of converter transformer under DC bias and harmonic is compared and analyzed. The specific contents are as follows: firstly, this paper introduces the method of measuring magnetic characteristics of electrical steel sheet. Based on the magnetic characteristic measurement system imported from Germany, the magnetic properties of silicon steel sheet under the action of alternating current magnetic field, alternating current magnetic field at different temperature, harmonic magnetic field and Q235B steel used in oil tank under harmonic magnetic field were measured. It includes B H curve and B P curve as well as hysteresis loop. Furthermore, the effects of temperature change, DC bias current change, harmonic frequency change and harmonic content change on the magnetic properties of electrical steel sheet are analyzed in detail. Secondly, according to the product level model data provided by the special transformer electrician co., Ltd., the 3D main magnetic field simulation model of the converter transformer is established by using the Magnet finite element software. In order to study the influence of magnetic characteristics of silicon steel sheet on the main magnetic field and core loss of converter transformer in different DC bias working states, the magnetic characteristic data of silicon steel sheet measured in the second chapter of this paper are presented. In this part, the magnetic properties of silicon steel sheet at room temperature (20 鈩，

本文編號(hào)：2119635