【摘要】：電纜的轉(zhuǎn)移阻抗是評(píng)估外界的電磁場(chǎng)能量通過(guò)電纜的屏蔽層的參數(shù)。測(cè)量電纜轉(zhuǎn)移阻抗是衡量電纜屏蔽效能的主要方法,其理論模型在很早以前已經(jīng)提出,之后也不斷有依據(jù)各種簡(jiǎn)化的假設(shè)條件并加以改進(jìn)的模型。如需要獲得比較準(zhǔn)確的參數(shù),應(yīng)對(duì)轉(zhuǎn)移阻抗作實(shí)際測(cè)量。線(xiàn)注入法、吸收鉗法以及三同軸法是目前主要的測(cè)量方法。本文選擇三同軸法。三同軸法顧名思義,是將被測(cè)電纜芯線(xiàn)、被測(cè)電纜屏蔽層以及外回流圓管固定在同一軸線(xiàn)上,形成三同軸結(jié)構(gòu)。測(cè)量電流的波形采用8/20μs波形。根據(jù)電纜屏蔽層性質(zhì)的不同,對(duì)屏蔽層為編織帶型的電纜注入1千安、2千安、3千安的電流,對(duì)屏蔽層為鋼鎧型的電纜注入1千安、5千安、10千安的電流,分別測(cè)量了一些不同型號(hào)電纜的轉(zhuǎn)移阻抗。測(cè)量過(guò)程中還考慮了不同的分流方法,分別采用了無(wú)分流、銅帶分流、扁鋼分流以及銅帶扁鋼共同分流的方式。由所得數(shù)據(jù)分析,低頻下,電纜屏蔽層的擴(kuò)散對(duì)于電纜的轉(zhuǎn)移阻抗起到?jīng)Q定性的作用,使其更接近于直流電阻;高頻下,轉(zhuǎn)移阻抗隨著頻率的增大而迅速增大,主要原因是由于外界的電磁場(chǎng)能量通過(guò)電纜屏蔽層上的孔洞與電纜的芯線(xiàn)發(fā)生耦合作用所致。此外,還根據(jù)理論公式作電纜轉(zhuǎn)移阻抗的理論值計(jì)算。對(duì)實(shí)際測(cè)量的結(jié)果和理論計(jì)算的結(jié)果作對(duì)比,分析誤差產(chǎn)生的原因。引入了套穿編織帶的方法,與這種注入電流的方法作對(duì)比,分別測(cè)量了一些不同型號(hào)電纜的轉(zhuǎn)移阻抗,在共有頻段內(nèi),兩種測(cè)試方法所得數(shù)據(jù)比較一致。
[Abstract]:The transfer impedance of the cable is the parameter to evaluate the external electromagnetic field energy passing through the shield layer of the cable. Measuring cable transfer impedance is the main method to measure cable shielding effectiveness. Its theoretical model has been put forward a long time ago, and then there are constantly improved models according to various simplified assumptions. If more accurate parameters are needed, the transfer impedance should be measured in practice. Line injection method, absorption clamp method and triaxial method are the main measurement methods at present. In this paper, the triaxial method is selected. The triaxial method, as the name implies, is to fix the measured cable core line, the shielding layer of the measured cable and the external reflux pipe on the same axis to form a triaxial structure. The waveform of measuring current is 8 / 20 渭 s waveform. According to the different properties of the cable shield layer, the cable with braided belt type is injected with 1, 2, 3, 3, 000, 1, 5, 10, 000, respectively. The transfer impedance of some different types of cables was measured. Different shunt methods are also considered in the measurement process, including no shunt, copper strip shunt, flat steel shunt and common shunt of copper strip flat steel. From the analysis of the obtained data, the diffusion of the cable shield plays a decisive role in the transfer impedance of the cable at low frequency, which makes it closer to the DC resistance. At high frequency, the transfer impedance increases rapidly with the increase of frequency, which is mainly due to the coupling of external electromagnetic field energy through holes in the shielding layer of the cable with the core of the cable. In addition, the theoretical value of cable transfer impedance is calculated according to the theoretical formula. The results of practical measurement are compared with those of theoretical calculation, and the causes of errors are analyzed. In this paper, the method of piercing braided belt is introduced, and compared with this method of injecting current, the transfer impedance of some different types of cables is measured respectively. in the common frequency band, the data obtained by the two methods are consistent.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TM75

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本文編號(hào)：2491583