【摘要】：大型電力變壓器中結構件的雜散損耗主要由漏磁場及其分布決定，分布集中的漏磁場會引起局部過熱，導致絕緣材料熱老化等問題，，從而影響變壓器運行的可靠性和壽命。為降低漏磁通所引起的損耗和溫升，在變壓器油箱、鐵心拉板等金屬部件上會廣泛分布磁、電屏蔽。普遍應用的磁屏蔽和電磁屏蔽均采用高導磁性能的取向硅鋼片疊積而成，故對其硅鋼片材料的電磁性能研究尤為重要。 本文首先研究了磁屏蔽材料，即硅鋼片的磁性能。通過對硅鋼試片進行愛潑斯坦方圈磁性能測量實驗，考察了等效磁路長度的影響因素（頻率，取樣角度，環(huán)境溫度）。由三維仿真計算，證明了雙愛潑斯坦方圈法的前提條件。為考慮其各部分對等效磁路長度的影響，提出了三方圈一級加權方法和二級加權處理法，確定25cm愛潑斯坦方圈的有效磁路長度，設計了功率分析儀WT3000和愛潑斯坦方圈組合測量激磁功率的實驗，并測量了不同平均磁密、取樣角度，不同的頻率、環(huán)境溫度的比總損耗及激磁功率。通過與雙方圈法的比較分析結果，體現(xiàn)出其優(yōu)越性。實驗結果與分析結論對進一步研究大型電力變壓器鐵心與磁屏蔽的磁性能具有工業(yè)應用價值。 其次，針對硅鋼片材料的應用，即磁屏蔽進行考察研究。然而屏蔽損耗難于直接測得，故需從所測得總損耗中將其分離出來。本文介紹了鏡像測量方法，可將漏磁通進行補償，以便能夠有效分離磁屏蔽的損耗，將鏡像模型進行二維建模與仿真分析，驗證鏡像測量法的合理性。根據(jù)保定天威集團電工技術研發(fā)中心進行改進的變壓器產(chǎn)品模型屏蔽損耗與磁密測量的實驗平臺，共進行了針對五種模型的實驗（立式磁屏蔽，平板式磁屏蔽，立式磁屏蔽與導磁鋼板組合模型，平板式磁屏蔽與導磁鋼板組合模型及電屏蔽與導磁鋼板組合模型）。 最后，用電磁場分析軟件MagNet V7.2對其進行三維建模和仿真，將激勵繞組進行均勻化處理，并考慮硅鋼片的磁各向異性與非線性，在不同激勵工況下，將模型的磁密與損耗詳細對比分析并進行有效的基準化模型實驗驗證，為實際產(chǎn)品應用提供了一定的參考價值。
[Abstract]:The stray loss of structural parts in large power transformers is mainly determined by the leakage magnetic field and its distribution. The concentrated leakage magnetic field will cause local overheating and lead to thermal aging of insulation materials, thus affecting the reliability and life of transformer operation. In order to reduce the loss and temperature rise caused by magnetic flux leakage, magnetic and electric shielding will be widely distributed in transformer fuel tank, iron core drawing plate and other metal parts. Both magnetic shielding and electromagnetic shielding are composed of oriented silicon steel sheets with high magnetic conductivity, so it is particularly important to study the electromagnetic properties of silicon steel sheet materials. In this paper, the magnetic properties of magnetic shielding material, that is, silicon steel sheet, are studied. The factors affecting the length of equivalent magnetic circuit (frequency, sampling angle, ambient temperature) were investigated by measuring the magnetic properties of Epstein square ring on silicon steel specimen. The precondition of double Epstein square circle method is proved by three dimensional simulation. In order to consider the influence of each part on the equivalent magnetic circuit length, the first-order weighting method and the second-order weighted processing method of the three-square ring are proposed to determine the effective magnetic circuit length of the 25cm Epstein square loop. The experiment of measuring the excitation power by the combination of the power analyzer WT3000 and the Epstein square ring is designed, and the specific total loss and excitation power of different average magnetic density, sampling angle, different frequency, environmental temperature and magnetic power are measured. Through the comparison and analysis with the double circle method, it shows its superiority. The experimental results and analysis results are of industrial application value for the further study of the magnetic energy of core and magnetic shield of large power transformers. Secondly, the application of silicon steel sheet material, that is, magnetic shielding, is investigated and studied. However, the shielding loss is difficult to be measured directly, so it needs to be separated from the measured total loss. In this paper, the mirror image measurement method is introduced, which can compensate the magnetic leakage flux so that the loss of magnetic shield can be separated effectively. The mirror model is modeled and simulated in two dimensions to verify the rationality of the mirror image measurement method. According to the improved experimental platform of transformer product model shielding loss and magnetic density measurement carried out by Baoding Tianwei Group Electrical Technology Research and Development Center, a total of experiments were carried out for five models (vertical magnetic shielding, flat plate magnetic shielding, vertical magnetic shielding and magnetic conductive plate combination model, flat plate magnetic shielding and magnetic conductive plate combination model and electric shielding and magnetic conductive steel plate combination model). Finally, the three-dimensional modeling and simulation of the electric magnetic field analysis software MagNet V7.2 is carried out, the excitation winding is homogenized, and the magnetic anisotropy and nonlinear of silicon steel sheet are considered. under different excitation conditions, the magnetic density and loss of the model are compared and analyzed in detail and verified by effective reference model experiments, which provides a certain reference value for the application of practical products.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM41;TM275

【參考文獻】

相關期刊論文 前1條

1 程志光,高生,胡啟凡,劉志光,吳明訓,劉玉仙;鋼中渦流和磁滯損耗問題[J];變壓器;1999年09期

本文編號：2497931