發(fā)布時間：2018-02-03 02:55

  本文關(guān)鍵詞： 電力電纜 暫態(tài)熱路模型 熱阻動態(tài)特性 絕緣層優(yōu)化分析 采樣頻率　出處：《華南理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：電力電纜導(dǎo)體溫度的在線監(jiān)測是確切掌握電纜運行狀態(tài)的重要手段，也是指導(dǎo)線路負荷調(diào)度、運行維護及提高線路利用率的有效方法。本文在廣州供電局有限公司重點科技項目的支持下，開展了用于單芯電纜導(dǎo)體溫度在線監(jiān)測的暫態(tài)熱路模型研究，主要工作如下： 1.電纜各層材料熱阻的動態(tài)特性研究。提出了鋁護套至導(dǎo)體間的熱阻物理模型，分析了溫度對熱阻的影響，通過電纜載流溫升實驗得到實驗熱阻值隨溫度的變化曲線，定量分析了其變化規(guī)律，并對比熱阻的理論計算值和實驗值，為電纜載流量的計算和導(dǎo)體溫度在線監(jiān)測提供了依據(jù)。 2.電纜暫態(tài)熱路模型的優(yōu)化建模研究。詳細論證了電纜暫態(tài)熱路模型的構(gòu)建及模型本身的誤差，通過引入熱擴散率得到電纜各層對傳熱的影響，然后重點針對絕緣層的建模進行優(yōu)化分析，，構(gòu)建了絕緣層按照等厚度、厚度比、等熱容、熱容比四種方法建模的暫態(tài)熱路模型，編輯Matlab程序?qū)崿F(xiàn)絕緣層在四種建模方法下的任意分層，并結(jié)合電纜載流溫升實驗，定量分析了絕緣層分層數(shù)對模型誤差的影響規(guī)律，得到實驗電纜的最優(yōu)暫態(tài)熱路模型。 3.采樣頻率和模型結(jié)構(gòu)對誤差的共同影響。在分析電纜熱時間常數(shù)的基礎(chǔ)上，通過實驗得到不同采樣頻率下電纜導(dǎo)體溫度的變化速率，論證了電纜暫態(tài)熱路模型可以由積分解變換為差分解，并在上述四種暫態(tài)熱路模型的基礎(chǔ)上，重點研究工程應(yīng)用中極其重要的采樣頻率對模型誤差的影響，結(jié)合電纜載流溫升實驗得到采樣頻率和模型結(jié)構(gòu)對誤差的共同影響，為電纜暫態(tài)熱路模型的工程應(yīng)用打下基礎(chǔ)。
[Abstract]:On-line monitoring of the conductor temperature of power cable is an important means to master the operating state of the cable, and it is also an important means to guide the load dispatching of the line. Under the support of the key science and technology project of Guangzhou Power supply Bureau Ltd, the transient heat path model for the on-line monitoring of conductor temperature of single core cable is studied in this paper. The main tasks are as follows: 1. Research on the dynamic characteristics of thermal resistance of different layers of cable. A physical model of thermal resistance between aluminum sheath and conductor is proposed, and the influence of temperature on thermal resistance is analyzed. The curves of experimental heat resistance with temperature are obtained by the experiment of cable current temperature rise. The variation law of thermal resistance is quantitatively analyzed, and the theoretical and experimental values of thermal resistance are compared. It provides the basis for the calculation of cable load current and the on-line monitoring of conductor temperature. 2. Research on the optimal modeling of cable transient thermal circuit model. The construction of cable transient thermal circuit model and the error of the model itself are demonstrated in detail, and the influence of each layer of cable on heat transfer is obtained by introducing thermal diffusivity. Then the optimization analysis is focused on the insulation layer modeling, and the transient heat path model is built according to the constant thickness, thickness ratio, equal heat capacity and heat capacity ratio. The arbitrary stratification of insulation layer under four modeling methods is realized by editing Matlab program, and the influence of insulation layer number on model error is quantitatively analyzed in combination with the experiment of cable current carrying temperature rise. The optimal transient thermal circuit model of experimental cable is obtained. 3. The influence of sampling frequency and model structure on the error. Based on the analysis of cable thermal time constant, the temperature change rate of cable conductor at different sampling frequencies is obtained by experiments. It is demonstrated that the cable transient thermal circuit model can be transformed from integral solution to differential decomposition. On the basis of the above four transient heat path models, the influence of sampling frequency on the model error is studied. The influence of sampling frequency and model structure on the error is obtained by combining the current carrying temperature rise experiment of cable, which lays a foundation for the engineering application of cable transient thermal circuit model.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM247

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本文編號：1486211