直流偏磁及谐波条件下换流变压器损耗问题研究
发布时间：2018-07-13 14:08
【摘要】：在高压直流输电系统中,换流站本身的工作性质导致换流变压器中存在大量的谐波及直流偏磁现象。谐波将引起换流变压器损耗增加、电气绝缘破坏及局部过热等问题;同时,直流偏磁将对换流变压器的正常运行带来一系列危害,如励磁电流发生畸变、谐波及损耗增加、振动及噪声加剧、铁心绑带松脱、铁心柱弯曲、铁心片串片等,因此在产品设计过程中准确分析计算直流偏磁及谐波影响下换流变压器的损耗问题,对降低系统谐波及损耗、提高换流变压器稳定性具有重要的意义。由于不同激励对电工钢片磁特性影响不同,准确分析换流变压器的电磁性能离不开对电工钢片磁特性的准确描述,因此本文测量分析了直流偏置激励、非正弦激励及不同温度条件下电工钢片的磁特性,并将测得的数据应用到换流变压器相应运行状态的损耗计算中,对比分析了电工钢片磁特性的变化对计算直流偏磁及谐波条件下换流变压器磁场及损耗的影响,具体工作内容如下:首先,本文介绍了电工钢片磁特性测量的方法,基于德国进口的磁特性测量系统,测量了不同温度的交流磁场、交直流磁场以及谐波磁场作用下硅钢片的磁特性和谐波磁场作用下油箱所用材料Q235B钢的磁特性,包括B-H曲线、B-P曲线以及磁滞回线。进而具体分析了温度变化、直流偏磁电流变化、谐波次数变化及谐波含量变化对电工钢片磁特性的影响。其次,根据特变电工股份有限公司提供的产品级模型数据,运用MagNet有限元软件建立了该换流变压器的三维主磁场仿真模型。为了研究硅钢片磁特性变化对不同直流偏磁工作状态的换流变压器主磁场及铁心损耗的影响,基于本文第二章所测得的硅钢片磁特性数据,本部分采用场路耦合的方法在瞬态场中考虑了无直流偏磁室温(20℃)条件下与不同直流偏磁工作温度(80℃)条件下硅钢片的磁特性。最终将上述结果与试验值进行了对比,证明了本文所提出改进计算方法的可靠性。最后,根据特变电工股份有限公司提供的产品级模型数据,运用MagNet有限元软件建立了该换流变压器的三维漏磁场仿真模型。为了研究硅钢片、Q235B钢磁特性变化对谐波作用下换流变压器漏磁场及结构件杂散损耗的影响,基于本文第二章所测得的电工钢片磁特性数据,本部分采用场路耦合的方法在瞬态场中考虑了无谐波工作温度(80℃)条件下和含有谐波工作温度(80℃)条件下硅钢片、Q235B钢磁特性。然后运用IEC 61378-2标准计算了谐波条件下换流变压器的结构件杂散损耗,并给出了以上方法计算结果与试验值的对比,验证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，
本文编号：2119635
[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，
本文编号：2119635
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