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大電網(wǎng)地磁感應電流影響因素及建模方法研究

發(fā)布時間:2019-05-19 12:11
【摘要】:地磁感應電流(GIC)可能對電網(wǎng)安全運行產(chǎn)生不利的影響。隨著特高壓電網(wǎng)的建設,我國已成為世界上電網(wǎng)規(guī)模最大、電壓等級最多的國家,結(jié)合我國緯度(磁緯)跨度大、大地電性構(gòu)造復雜多樣等實際情況,我國電網(wǎng)可能存在較高的GIC災害風險。因此,探明中低緯地區(qū)GIC的各種影響因素及其作用機理與影響程度,建立適合中低緯電網(wǎng)以及我國大地條件的GIC計算模型及方法是必要和緊迫的任務;谥械途旼IC準確計算的重大需求,本論文從空間、大地、電網(wǎng)三方面的影響因素入手,圍繞電網(wǎng)GIC的建模開展了研究,主要工作及成果如下: 針對電離層空間電流源對GMD感應地電場的影響差異,定義了“大小源電流”兩種典型極限電流源模型。根據(jù)電磁感應理論及快速漢克分解等解析方法,從場源水平距離、垂直距離和電流頻率三方面對“大小源電流”模型下的地表阻抗特性進行了數(shù)值模擬和解析證明。研究結(jié)果表明“線電流模型計算出的感應地電場總小于面電流模型的計算結(jié)果”的說法不準確,并針對中低緯地區(qū)感應地電場計算提出了采用“大源電流”模型的計算思路與方法。 以“萬圣節(jié)GMD事件”為例,從頻域和時域兩方面定量分析了不同緯度及大地電導率模型對感應地電場的影響。結(jié)果表明對于中低緯地區(qū)的電網(wǎng),雖然地磁擾動強度相對較低,但大地電性構(gòu)造的差異可能會使感應地電場相差4-10倍,提出了利用"GIC-Benchmark"算例模型分析大地因素對電網(wǎng)GIC影響的方法,證明了由于大地電導率的影響中低緯地區(qū)的GIC可能高于高緯地區(qū)。 結(jié)合電網(wǎng)實際參數(shù)和特點,研究了輸電線路長度、電網(wǎng)拓撲結(jié)構(gòu)以及變壓器結(jié)構(gòu)對GIC的影響。結(jié)果表明:輸電線路較短時,GIC水平與線路長度呈近似線性關(guān)系,當線路達到一定長度時,GIC水平與線路長度無關(guān),趨于飽和值;對變電站的GIC計算要考慮與其相連的所有輸電線路的共同作用;另外,變電站的GIC受“拐點效應”影響,終端變電站的GIC更大;考慮變壓器類型、結(jié)構(gòu)等因素的影響,給出了自耦變壓器和普通單相變壓器的GIC有效值的計算方法。 根據(jù)變壓器繞組聯(lián)結(jié)方式和不同類型變壓器組合模式,結(jié)合節(jié)點導納矩陣算法,提出了多電壓等級電網(wǎng)GIC的建模技術(shù)與計算方法,解決了由不同電壓等級輸電線路GIC相互作用引起的變電站GIC的準確計算問題。在此基礎(chǔ)上,建立了三華電網(wǎng)全節(jié)點GIC計算模型,研究了500kV電網(wǎng)和1000kV特高壓電網(wǎng)之間GIC的相互影響,發(fā)現(xiàn)當接入1000kV變電站的500kV線路關(guān)于電場方向不對稱時,500kV線路GIC對1000kV變電站GIC影響較大。 本論文綜合考慮了空間、大地和電網(wǎng)三方面因素的影響,提出了多電壓等級大電網(wǎng)GIC的建模和計算方法,揭示了不同電壓等級電網(wǎng)GIC相互作用的特征規(guī)律,并利用2015年三華規(guī)劃電網(wǎng)參數(shù)完成了建模理論與方法的實證研究。三華電網(wǎng)在實際地磁擾動作用下GIC水平的計算結(jié)果表明,受次級電網(wǎng)GIC的影響特高壓電網(wǎng)可能存在較高的GIC災害風險。因此本論文提出了特高壓電網(wǎng)防御磁暴災害的技術(shù)方案,對我國下一步重大的電網(wǎng)工程建設和安全運行具有實際意義。
[Abstract]:Geomagnetic induced current (GIC) may have an adverse effect on the safe operation of the power grid. With the construction of the extra-high voltage power network, China has become the largest and most voltage-grade country in the world, and in combination with the actual conditions of the latitude (magnetic pick-up) span of China and the complex and diverse earth's electrical structure, China's power grid may have a high risk of GIC disaster. Therefore, it is necessary and urgent to establish the GIC calculation model and method suitable for the low-latitude and low-latitude grid and the ground conditions in China. Based on the important demand of the accurate calculation of the mid-and low-latitude GICs, this paper starts with the influence factors of the space, the earth and the power grid, and studies the modeling of the power grid GIC. The main work and results are as follows: The influence of the ionospheric space current source on the electric field induced by GMD In this paper, two typical limiting current source modes of the "size source current" are defined Based on the analytical methods of the electromagnetic induction theory and the rapid Hanks decomposition, the surface impedance characteristics under the "size source current" model are simulated and analyzed from the field source horizontal distance, the vertical distance and the current frequency. The results show that the formula of the induced ground electric field is less accurate than that of the surface current model, and the calculation method and the method of using the large-source current model are proposed for the calculation of the induced ground electric field in the middle and low latitude regions. By taking the "Halloween GMD Events" as an example, the electric field induced by the different latitude and the ground conductivity model is quantitatively analyzed from the frequency domain and the time domain The results show that, for the power grid in the mid-low latitude area, although the geomagnetic disturbance intensity is relatively low, the difference of the ground electrical structure may cause the induced electric field to differ by 4-10 times, and the influence of the ground factors on the GIC of the power grid is analyzed by using the "GIC-Benchmark" example model. The method has proved that the GIC in the low-latitude area may be higher than the high-latitude area due to the influence of the earth's electrical conductivity Based on the actual parameters and characteristics of the power grid, the length of the transmission line, the topological structure of the power grid and the structure of the transformer are studied. The results show that, when the transmission line is short, the GIC level is approximately linear with the length of the line, and when the line reaches a certain length, the GIC level is independent of the line length and tends to be saturated. The GIC calculation of the substation shall consider the joint of all the power transmission lines connected with it. In addition, the GIC of the substation is affected by the "inflection point effect", and the GIC of the terminal substation is larger; considering the influence of the transformer type, structure and other factors, the GIC effective value of the self-coupling transformer and the common single-phase transformer is given According to the method of transformer winding and the combination mode of different types of transformer and the algorithm of node admittance matrix, the modeling of a multi-voltage-grade grid GIC is put forward. The technology and the calculation method solve the GIC of the substation caused by the interaction of the GICs of the power transmission lines with different voltage levels. On the basis of this, the whole node GIC calculation model of the three-China power network is established, and the interaction of the GICs between the 500 kV power grid and the 1000kV UHV power grid is studied. It is found that when the 500kV line of the 1000kV substation is not symmetrical with respect to the direction of the electric field, the 500kV line GIC is used for the 1000kV transformer substation. The influence of the three factors of space, earth and power grid is considered in this paper. The modeling and calculation method of the large power grid GIC with multiple voltage levels is put forward, and the GICs of different voltage levels are revealed. The characteristic law of the interaction is realized, and the modeling method is completed by using the parameters of the three-China planned power grid in 2015. The results of the calculation of the GIC level under the effect of the actual geomagnetic disturbance of the three-China power grid show that the influence of the secondary grid GIC on the UHV power grid may be more Therefore, this paper puts forward the technical scheme of the high-voltage power network to prevent the magnetic storm disaster, and has made a great contribution to the construction and safety of the next major grid engineering in our country.
【學位授予單位】:華北電力大學
【學位級別】:博士
【學位授予年份】:2014
【分類號】:TM711

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