本文選題：電壓源型直流電網(wǎng)　切入點(diǎn)：直流電網(wǎng)控制策略　出處：《華中科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：世界各國已經(jīng)開始了能源結(jié)構(gòu)的調(diào)整,可再生能源相對于傳統(tǒng)能源所具備的優(yōu)勢使其得到快速發(fā)展�？稍偕茉窗l(fā)電技術(shù)的研究和大規(guī)模應(yīng)用給電力系統(tǒng)帶來了新的挑戰(zhàn)和機(jī)遇,如何應(yīng)對大規(guī)�？稍偕茉唇尤腚娏ο到y(tǒng)后遠(yuǎn)距離傳輸以及及時消納等問題,成為學(xué)界熱烈探討的議題。相比于交流輸電技術(shù),直流輸電技術(shù)更適合于非同步交流系統(tǒng)的互聯(lián)、大容量可再生能源遠(yuǎn)距離輸電等應(yīng)用場合。從直流輸電技術(shù)的發(fā)展歷程來看,電壓源型直流電網(wǎng)技術(shù)將會是直流輸電技術(shù)在未來的發(fā)展方向。本文選取了電壓源型直流電網(wǎng)協(xié)調(diào)控制策略和直流故障特性兩個切入點(diǎn),采用PSCAD/EMTDC這一仿真軟件對這兩部分內(nèi)容進(jìn)行研究,完成的研究工作及取得主要研究成果包括:介紹了直流電網(wǎng)建模中使用的兩種電壓源型換流器,研究了能夠模擬穩(wěn)態(tài)特性和故障特性的兩電平電壓源型換流器和模塊化多電平換流器快速模型;比較研究了環(huán)形、輻射型、網(wǎng)狀和混合式等不同拓?fù)渲绷麟娋W(wǎng)的靈活性和經(jīng)濟(jì)性,研究表明,各類拓?fù)渲绷麟娋W(wǎng)均具備其適用的應(yīng)用場景�；诓捎没旌鲜酵�?fù)涞奈宥酥绷麟娋W(wǎng),研究了主從控制、主從備用控制、直流電壓偏差控制和直流電壓下垂控制等直流電網(wǎng)控制策略及其特性;在此基礎(chǔ)上提出了一種主從-下垂協(xié)調(diào)控制策略,五端直流電網(wǎng)算例仿真研究表明,采用主從-下垂協(xié)調(diào)控制策略,在輸入功率波動、換流站功率反向等情況下,能夠精確跟蹤電壓和功率指令值,在主換流站退出運(yùn)行的工況下能夠快速平穩(wěn)地轉(zhuǎn)換至新的控制模式。分別建立了環(huán)形、輻射型和網(wǎng)狀等三種典型拓?fù)渲绷麟娋W(wǎng),仿真研究了不同換流站出口處直流極間短路故障時直流電網(wǎng)短路電流特性。結(jié)果表明,直流電網(wǎng)中短路電流上升速度極快、峰值極大,最大短路電流的分布和峰值大小與直流電網(wǎng)拓?fù)�、故障點(diǎn)位置和線路參數(shù)相關(guān)。建立了混合式高壓直流斷路器詳細(xì)與簡化仿真模型,針對連接交流電壓源、交流負(fù)荷、永磁式直驅(qū)風(fēng)力發(fā)電機(jī)或雙饋式感應(yīng)風(fēng)力發(fā)電機(jī)的單個直流節(jié)點(diǎn)極間短路故障,仿真研究了該類型斷路器開斷故障電流的暫態(tài)過程,驗(yàn)證了其開斷能力。
[Abstract]:Countries around the world have begun to adjust their energy structure. The rapid development of renewable energy is due to its advantages over traditional energy. The research and large-scale application of renewable energy power generation technology bring new challenges and opportunities to the power system. How to deal with the problems of long-distance transmission and timely absorption after large-scale renewable energy access to power systems has become a hot topic in academic circles. Compared with AC transmission technology, DC transmission technology is more suitable for the interconnection of asynchronous AC systems. Large capacity renewable energy long-distance transmission and other applications. From the development of DC transmission technology, Voltage source DC network technology will be the future development direction of HVDC transmission technology. In this paper, the coordinated control strategy and DC fault characteristics of voltage source DC power network are selected. The PSCAD/EMTDC simulation software is used to study these two parts. The research work and the main research results are as follows: two voltage source converters used in DC network modeling are introduced. The fast models of two-level voltage source converter and modularized multilevel converter which can simulate steady and fault characteristics are studied. The flexibility and economy of different topology DC networks, such as mesh network and hybrid DC network, are studied. It is shown that all kinds of topological DC networks have their applicable application scenarios. Based on the five-terminal DC network with hybrid topology, the master-slave control is studied. The main slave backup control, DC voltage deviation control, DC voltage droop control and other DC voltage droop control strategies and their characteristics are proposed, and a master-slave droop coordination control strategy is proposed. By adopting master-slave droop coordinated control strategy, the voltage and power instruction values can be accurately tracked in the case of input power fluctuation and converter station power reverse, etc. When the main converter station is out of operation, it can quickly and smoothly switch to the new control mode. Three typical topology direct current networks, ring, radiation and mesh, are established respectively. The characteristics of short-circuit current in DC network with short-circuit fault between DC poles at the outlet of different converter stations are studied by simulation. The results show that the short-circuit current in DC network is rising very fast and the peak value is very high. The distribution and peak value of maximum short-circuit current are related to DC network topology, fault location and line parameters. A detailed and simplified simulation model for hybrid HVDC circuit breakers is established to connect AC voltage source and AC load. The short-circuit fault between the poles of a single DC node of a permanent magnet direct-drive wind generator or a doubly-fed induction wind generator is studied. The transient process of the on-off fault current of this type of circuit breaker is simulated and its breaking capacity is verified.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM721.1

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本文編號：1580643