雷擊高塔地閃回?fù)綦姶泡椛涮卣餮芯?/H1>
發(fā)布時間：2018-10-20 17:36
【摘要】：高塔更易形成上行先導(dǎo),因此更易成為雷電擊中的目標(biāo),而高塔的暫態(tài)效應(yīng),使得雷擊高塔產(chǎn)生的電磁輻射與雷擊地面的情況存在明顯差異。關(guān)于雷擊高塔的電磁輻射已有大量研究,然而土壤色散效應(yīng)對于雷擊高塔電磁輻射的影響尚未開展。所謂土壤色散效應(yīng),是指在不同頻率條件下,土壤電參數(shù)表現(xiàn)出不同的特征。在低頻條件下,土壤電參數(shù)趨于恒定,可以假定土壤電參數(shù)恒定；而在高頻條件下,土壤電導(dǎo)率會變小。此外,目前雷電回?fù)綦姶艌鲈谥懈邔痈叨鹊难芯?均假定雷電擊中地面,未考慮高塔存在的影響。因此,本文主要研究了土壤色散效應(yīng)對雷電回?fù)綦姶泡椛涞挠绊?以及高塔暫態(tài)效應(yīng)對于中高層高度電磁瞬態(tài)特征的影響。本文通過對不同色散模型的對比分析,選取了相關(guān)性系數(shù)最優(yōu)的色散模型用于雷擊高塔的回?fù)綦姶艌鲇嬎?討論了土壤色散效應(yīng)對雷擊高塔回?fù)綦姶艌龅挠绊憲l件,在此基礎(chǔ)上,對雷擊高塔電流峰值反演因子FCCFs(Field-to-Current Conversion Factors)進(jìn)行了修訂。此外,本文研究了雷擊高塔回?fù)綦姶艌鲈谥懈邔痈叨鹊碾姶艌鏊矐B(tài)變化特征,對比雷擊地面的情況,分析了高塔對中高層瞬態(tài)電磁場的影響。針對以上研究,取得具體成果如下：本文對比了六種色散模型,通過Kramers-Kronig檢驗,計算了各模型的相關(guān)性,選取了相關(guān)性最優(yōu)的Portela模型。研究了雷擊50-300 m高塔時,土壤色散效應(yīng)對雷電電磁場沿地表面?zhèn)鞑r的影響。研究發(fā)現(xiàn),當(dāng)考慮土壤色散效應(yīng)時,雷擊高塔電磁場沿地表傳播時的衰減程度明顯小于電參數(shù)恒定時的結(jié)果。當(dāng)土壤恒定電導(dǎo)率大于0.01 S/m時,土壤色散效應(yīng)的影響可以忽略,而小于0.001S/m時,則需要考慮色散效應(yīng)的影響。比如,當(dāng)土壤恒定電導(dǎo)率等于0.0001 S/m,考慮色散效應(yīng)時,雷擊300 m高塔在100 km處的電磁場峰值是恒定電參數(shù)情況下的2.5倍。利用研究結(jié)果修訂了雷電流反演因子FCCFs,經(jīng)過修訂后的誤差在10%以內(nèi),反演精度顯著提高。本文還模擬了雷電擊中50-300m高塔時中高層的瞬態(tài)電場,研究了高塔存在對中高層瞬態(tài)電場的影響。由于高塔對雷電流的暫態(tài)效應(yīng),對于波頭時間RT在0.2us～2us范圍內(nèi)的繼后回?fù)綦娏鞫?其產(chǎn)生的電場峰值增大,高頻分量也相應(yīng)增多。當(dāng)波頭時間RT減小或塔高增加,電場的峰值則越大。當(dāng)RT為0.2us的雷電流擊中300 m高塔時,在80k m高度、水平距離80 km處產(chǎn)生的輻射場是擊中地面所產(chǎn)生的電場峰值的數(shù)倍；隨著波頭時間RT的增加,擊中高塔的閃電在遠(yuǎn)場上的高塔存在的影響會逐漸變小。
[Abstract]:The tower is easier to form the upward lead, so it is easier to be the target of lightning strike, and the transient effect of the tower makes the electromagnetic radiation produced by the lightning tower is obviously different from that of the lightning strike ground. Much research has been done on the electromagnetic radiation of lightning tower, but the effect of soil dispersion on the electromagnetic radiation of lightning tower has not been carried out. The so-called soil dispersion effect refers to the different characteristics of soil electrical parameters under different frequency conditions. Under the condition of low frequency, the electric parameters of the soil tend to be constant, which can be assumed to be constant, but the conductivity of the soil becomes smaller under the condition of high frequency. In addition, the current research on the height of lightning return stroke electromagnetic field in the middle and high level assumes that the lightning strikes the ground without considering the influence of the tower. Therefore, the influence of soil dispersion effect on electromagnetic radiation of lightning return stroke and the influence of tower transient effect on high electromagnetic transient characteristics of middle and high level are studied in this paper. Based on the comparative analysis of different dispersion models, the optimal dispersion model with correlation coefficient is selected to calculate the electromagnetic field of lightning tower, and the influence of soil dispersion on the electromagnetic field of lightning tower is discussed. On this basis, the inversion factor FCCFs (Field-to-Current Conversion Factors) for the peak current of lightning tower is revised. In addition, this paper studies the transient characteristics of the electromagnetic field of the lightning tower at the height of the middle and high levels, compares the lightning strike on the ground, and analyzes the influence of the tower on the transient electromagnetic field of the middle and high levels. The results are as follows: in this paper, six dispersion models are compared, the correlation of each model is calculated by Kramers-Kronig test, and the optimal Portela model is selected. The effect of soil dispersion on the propagation of lightning electromagnetic field along the ground surface was studied when lightning struck 50-300 m tall tower. It is found that the attenuation degree of electromagnetic field of lightning tower is obviously less than that of constant electric parameters when considering the dispersion effect of soil. When the constant conductivity of soil is greater than 0. 01 S / m, the effect of soil dispersion can be neglected, but when the soil conductivity is less than 0. 01 S / m, the influence of dispersion effect should be considered. For example, when the constant conductivity of the soil is equal to 0.0001 S / m and the dispersion effect is considered, the peak value of the electromagnetic field of the 300m lightning tower at 100 km is 2.5 times higher than that under the constant electrical parameters. Based on the results of the study, the correction error of the lightning current inversion factor (FCCFs,) is less than 10%, and the inversion accuracy is improved significantly. This paper also simulates the transient electric field in the middle and upper layers when lightning strikes 50-300m tall tower, and studies the influence of the tower on the transient electric field in the middle and high layers. Because of the transient effect of tower on lightning current, the peak electric field and the high frequency component of wave head time RT in the range of 0.2us~2us increase. When the RT of the wave head decreases or the tower height increases, the peak value of the electric field increases. When the lightning current with RT of 0.2us hits the 300m tower, the radiation field at 80km height and 80 km horizontal distance is several times the peak value of the electric field generated by hitting the ground, with the increase of the wave head time RT. The impact of lightning striking the tower on the far field becomes smaller.
【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P427.3;O441.4
【參考文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前1條
1 馮建偉;高塔對雷擊電流及其電磁輻射環(huán)境的影響[D];南京信息工程大學(xué);2011年
，
本文編號：2283897
本文鏈接：http://sikaile.net/kejilunwen/dianzigongchenglunwen/2283897.html
[Abstract]:The tower is easier to form the upward lead, so it is easier to be the target of lightning strike, and the transient effect of the tower makes the electromagnetic radiation produced by the lightning tower is obviously different from that of the lightning strike ground. Much research has been done on the electromagnetic radiation of lightning tower, but the effect of soil dispersion on the electromagnetic radiation of lightning tower has not been carried out. The so-called soil dispersion effect refers to the different characteristics of soil electrical parameters under different frequency conditions. Under the condition of low frequency, the electric parameters of the soil tend to be constant, which can be assumed to be constant, but the conductivity of the soil becomes smaller under the condition of high frequency. In addition, the current research on the height of lightning return stroke electromagnetic field in the middle and high level assumes that the lightning strikes the ground without considering the influence of the tower. Therefore, the influence of soil dispersion effect on electromagnetic radiation of lightning return stroke and the influence of tower transient effect on high electromagnetic transient characteristics of middle and high level are studied in this paper. Based on the comparative analysis of different dispersion models, the optimal dispersion model with correlation coefficient is selected to calculate the electromagnetic field of lightning tower, and the influence of soil dispersion on the electromagnetic field of lightning tower is discussed. On this basis, the inversion factor FCCFs (Field-to-Current Conversion Factors) for the peak current of lightning tower is revised. In addition, this paper studies the transient characteristics of the electromagnetic field of the lightning tower at the height of the middle and high levels, compares the lightning strike on the ground, and analyzes the influence of the tower on the transient electromagnetic field of the middle and high levels. The results are as follows: in this paper, six dispersion models are compared, the correlation of each model is calculated by Kramers-Kronig test, and the optimal Portela model is selected. The effect of soil dispersion on the propagation of lightning electromagnetic field along the ground surface was studied when lightning struck 50-300 m tall tower. It is found that the attenuation degree of electromagnetic field of lightning tower is obviously less than that of constant electric parameters when considering the dispersion effect of soil. When the constant conductivity of soil is greater than 0. 01 S / m, the effect of soil dispersion can be neglected, but when the soil conductivity is less than 0. 01 S / m, the influence of dispersion effect should be considered. For example, when the constant conductivity of the soil is equal to 0.0001 S / m and the dispersion effect is considered, the peak value of the electromagnetic field of the 300m lightning tower at 100 km is 2.5 times higher than that under the constant electrical parameters. Based on the results of the study, the correction error of the lightning current inversion factor (FCCFs,) is less than 10%, and the inversion accuracy is improved significantly. This paper also simulates the transient electric field in the middle and upper layers when lightning strikes 50-300m tall tower, and studies the influence of the tower on the transient electric field in the middle and high layers. Because of the transient effect of tower on lightning current, the peak electric field and the high frequency component of wave head time RT in the range of 0.2us~2us increase. When the RT of the wave head decreases or the tower height increases, the peak value of the electric field increases. When the lightning current with RT of 0.2us hits the 300m tower, the radiation field at 80km height and 80 km horizontal distance is several times the peak value of the electric field generated by hitting the ground, with the increase of the wave head time RT. The impact of lightning striking the tower on the far field becomes smaller.
【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P427.3;O441.4
【參考文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前1條
1 馮建偉;高塔對雷擊電流及其電磁輻射環(huán)境的影響[D];南京信息工程大學(xué);2011年
，本文編號：2283897
本文鏈接：http://sikaile.net/kejilunwen/dianzigongchenglunwen/2283897.html
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