臺灣博碩士論文加值系統

中文摘要

在變壓器的性能中，其外殼內的流場現象具有舉足輕重的影響，因此若是在瞭解與分析變壓器外殼內的流場現象方面有更進一步的發展，將有助於變壓器的設計。變壓器是一可將不同電壓系統之電能作任意有效連結之器械，也是現今工業動力的主要來源。在本研究中所使用來模擬分析一真實變壓器的Icepak計算流體力學程式，是由美國Fluent公司針對電子業模擬分析熱流現象所發展出的一套程式，該程式可用於計算暫態、二維、三維以及含有多種紊流模式之流場。

本研究使用之Icepak計算流體力學程式係以有限體積法進行數值計算，使用強大且快速的Multigrid功能與分離演算法，其提供非結構式網格處理複雜幾何模型，同時亦有操作簡易功能齊全之套裝模組以供使用者建立模型。

本研究計畫探討油浸式電力變壓器於氣冷狀態下內部自然對流之溫度與流場，並與變壓器理論計算及實際試驗佐證比對，以探討Icepak軟體利用於變壓器溫升模擬之合宜性與應用程序及法則。分析結果顯示，模擬個案在變壓器鐵心、繞組等方面均有合理之吻合度，同時推算所得之最高溫位置可做為變壓器溫度感測器設置位置之參考。此外，可進行變壓器散熱器配置方式之進階研究，提前驗得知溫升試驗結果，並減少漫長之實驗時間與降低開發該產品之成本。本文研究所建立之分析程序與法則未來將對油浸、乾式、模鑄、氣體絕緣等各式變壓器之進階研究具實質助益。

Abstract


The flow field inside the tank of a transformer has a major impact on the performance of the transformer. As a result, it is essential for the design of the device to have an in-depth understanding of the flow field. Transformer is an effective electrical device for the connection of tow power systems and a major power source for the industry.

In this study, the computational fluid dynamics (CFD) software Icepak, developed by the Fluent Company, was used to evaluate the thermal management of the various electronic devices. Icepak was based on the finite volume algorithm for the numerical simulation, with the capabilities for determining the transient, 2-D, and 3-D flow fields. It has a number of turbulence models with powerful, multi-grid and parallel numerical processing. In addition, it provides the unstructured grid generation capability to handle the complicated geometrical modeling. Furthermore, it has the easy-to-use modules for the users to choose.

This study investigated the temperature and flow fields of an oil-cooled power transformer with internally natural convection as the cooling means. The study used theoretical calculations and the numerical simulations; their respective results were compared with the experimental results. The purpose for this study was to evaluate the adequacy of the methodology and procedure by using the Icepak software package to determine the thermal management of a power transformer. The results obtained from the Icepak calculations indicated that the peak temperatures obtained for the core and the winding of transformer were in reasonable agreement with those obtained from the experimental results. In addition, the location for the peak temperature obtained from the Icepak calculations could be used for pinpointing the location of the temperature sensing devices. Furthermore, in-depth study of the arrangement of the cooling device used for the power transformer could predict valuable information of the temperature rise for the configuration under the tests. This could cut down the time and cost required for the development of the new product for the transformer.

The methodology and procedure established by this study can certainly be extended to determine the temperature and flow fields for a number of other power transformers different from the one studied in this thesis.

目 錄

中文摘要……………………………………………………………Ⅰ
英文摘要……………………………………………………………Ⅱ
致 謝 …………………………………………………………………III
目 錄…………………………………………………………………IV
表目錄…………………………………………………………………VI
圖目錄………………………………………………………………VII
符號說明……………………………………………………………IX
第一章 緒論…………………………………………………………1
1-1 引言………………………………………………………1
1-2 文獻回顧…………………………………………………5
第二章 變壓器介紹…………………………………………………11
2-1 變壓器理論……………………………………………11
2-2 變壓器分類……………………………………………11
2-3 變壓器主要構造…………………………………………13
2-3.1 變壓器之鐵心………………………………………13
2-3.2 變壓器之繞組………………………………………15
2-3.3 變壓器之散熱………………………………………17
2-4 變壓器之損失……………………………………………18
2-5 變壓器損失之計算………………………………………19
2-6 變壓器溫度之計算………………………………………20
2-7 壓器溫度之規範………………………….……………23
第三章 數值方法…………………………………………………25
3-1 Icepak簡介…………………………………………………25
3-2 統御方程式…………………………………………………26
3-3 Zero-Equation紊流模式…………………………………27
3-4 平均雷諾數………………………………………………28
3-5 邊界條件…………………………………….……….……29
3-6 不可壓縮法則………………………………………………30
3-7 Buoyancy-Driven Flows與自然對流(Natural Convection)31
3-8 輻射………………………………………………………32
3-9 連續方程式…………………………………………………34
3-10 求解邏輯………………………………………………37
第四章 研究方法…………………………………………………38
4-1問題描述……………………………………………..39 4-2 基本假設…………………………………………..…39
4-3 網格建立…………………………………………..…41
4-4 數值計算…………………………………………..…43
4-5 設定參數…………………………………………..…44
4-6 理論計算…………………………………………..…44
4-7 實物驗證…………………………………………..…44
第五章 結果與討論……………………………………………51
5-1 模擬個案敘述……………………………………………51
5-2變壓器內流場現象說明…………………………………52
5-3變壓器內溫度場現象說明…………………………………53
5-4參數分析………………………………………………….…58
5-4.1 尺寸………………………………………………58
5-3.2 熱量………………………………………………60
5-3.3 材質與特性……………………………………61
5-5數值結果………..…………………………………62
5-6理論結果………..……………………………….…63
5-7實際試驗結果………..……………………………63
5-8結果比較………..…………………………………64
第六章 結論與未來展望…………………………………………84
6-1 結論……………………………………………………84
6-2 未來展望………………………………………………86
參考文獻……………………………………………………………87







表目錄

表2-1變壓器之分類…………………………………………………12
表2-2常用鐵心矽鋼帶特性表……….………………………………13
表2-3冷卻媒體基準溫度比較表……………………………………23
表2-4 各國規範溫升限制比較表……………………………………24
表4-1 變壓器原始條件表..…………………………………………38
表5-1周溫30℃鐵心數值溫度表…………………………………54
表5-2周溫30℃低壓繞組數值溫度表……………………………54
表5-3周溫30℃高壓繞組數值溫度表……………………………55
表5-4周溫30℃絕緣油上部油溫數值溫度表……………………56
表5-5周溫40℃數值結果溫度表…………………………………57
表5-6模型尺寸參數表…………..…………………………………60
表5-7模型熱量參數表…………..…………………………………61
表5-8材料特性參數表…………..…………………………………62
表5-9數值結果溫度簡表………..…………………………………63
表5-10理論結果溫度簡表...………..…………………………………63
表5-11實際試驗結果溫度簡表…….…………………………………64
表5-12結果溫度比較表…………….…………………………………64









圖目錄

圖1-1台灣電力公司供電系統簡圖(大同公司提供)..………..………10
圖2-1 變壓器理論簡圖………………………………………..………11
圖2-2 三相內鐵型變壓器之疊積鐵心圖…..…………………………14
圖2-3 變壓器實際鐵心疊積成形圖…………………..………………14
圖2-4 變壓器繞組外形圖………………………………..……………15
圖2-5 變壓器繞組與鐵心關係示意圖…..……………………………16
圖2-6變壓器心體圖…………..………………………………………17
圖2-7油浸自冷式變壓器內部油循環示意圖…………………..……17
圖2-8外殼加裝散熱片結構圖…..……………………………………18
圖3-1 有限體積非結構式網格圖…………..…………………………35
圖3-2 Icepak數值求解一覽圖………………..………………………37
圖4-1網格外觀外形立體圖……………………..……………………48
圖4-2周溫30℃網格數82500之計算結果曲線圖…….…………48
圖4-3周溫30℃網格數117000之計算結果曲線圖……...………49
圖4-4周溫30℃網格數197000之計算結果曲線圖……………..49
圖4-5變壓器2D之Auto-Cad三視圖………………..…………..50
圖5-1 X軸剖面流場Z方向視圖……………………………….…66
圖5-2 Y軸剖面流場Z方向視圖……………………….…………66
圖5-3 Z軸剖面流場Y方向視圖.…………………………………67
圖5-4 Z軸剖面流場速度圖…………………………...……………67
圖5-5繞組上端部Y軸剖面流場速度圖…………………..………68
圖5-6變壓器Y軸剖面軸向視圖…………………………….………68
圖5-7心體外之Z軸剖面流場速度圖……………………….………69
圖5-8周溫30℃之第一相腳鐵溫度場圖……………………………69
圖5-9周溫30℃之第二相腳鐵溫度場圖……………………………70
圖5-10周溫30℃之第三相腳鐵溫度場圖……………………………70
圖5-11周溫30℃之上部軛鐵溫度場圖………………………………71
圖5-12周溫30℃之下部軛鐵溫度場圖………………………………71
圖5-13周溫30℃之第一相低壓繞組溫度場圖………………………72
圖5-14周溫30℃之第二相低壓繞組溫度場圖………………………72
圖5-15周溫30℃之第三相低壓繞組溫度場圖………………………73
圖5-16周溫30℃之第一相高壓繞組溫度場圖………………………73
圖5-17周溫30℃之第二相高壓繞組溫度場圖………………………74
圖5-18周溫30℃之第三相高壓繞組溫度場圖………………………74
圖5-19周溫30℃之變壓器上部溫度場圖……………………………75
圖5-20周溫30℃之變壓器上部速度場向量圖………………………75
圖5-21周溫30℃之變壓器上部質量流率等量圖…………….….…76
圖5-22周溫40℃網格數117000之計算結果曲線圖……..…………76
圖5-23周溫40℃之第一相腳鐵溫度場圖……….…………….……77
圖5-24周溫40℃之第二相腳鐵溫度場圖.……………………………77
圖5-25周溫40℃之第三相腳鐵溫度場圖…………………….………78
圖5-26周溫40℃之上部軛鐵溫度場圖………….……….…………78
圖5-27周溫40℃之下部軛鐵溫度場圖…….…………….…………79
圖5-28周溫40℃之第一相低壓繞組溫度場圖…………………..…79
圖5-29周溫40℃之第二相低壓繞組溫度場圖…………..…………80
圖5-30周溫40℃之第三相低壓繞組溫度場圖…………..…………80
圖5-31周溫40℃之第一相高壓繞組溫度場圖…………..…………81
圖5-32周溫40℃之第二相高壓繞組溫度場圖…………..…………81
圖5-33周溫40℃之第三相高壓繞組溫度場圖….……..…………….82
圖5-34周溫40℃之變壓器上部溫度場圖….………..………………82
圖5-35周溫40℃之變壓器上部速度場向量圖….……..…………….83
圖5-36周溫40℃之變壓器上部質量流率等量圖….…..…………….83

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