發(fā)布時(shí)間：2018-06-05 21:34

  本文選題：有源配電網(wǎng) + 逆變型分布式電源　； 參考：《華北電力大學(xué)》2017年碩士論文

【摘要】：全世界范圍內(nèi)能源問(wèn)題和環(huán)境污染問(wèn)題日益嚴(yán)峻,傳統(tǒng)電網(wǎng)的集中發(fā)電遠(yuǎn)距離輸電模式又存在著電能損耗大、供電穩(wěn)定性較差等問(wèn)題,分布式電源(Distributed Generation,DG)因其清潔、靈活、可調(diào)性等優(yōu)點(diǎn)在配電網(wǎng)中應(yīng)用越來(lái)越廣泛。分布式電源的接入改變了配電網(wǎng)的單向電源供電模式,對(duì)傳統(tǒng)配電網(wǎng)的三段式電流保護(hù)產(chǎn)生了影響。本文通過(guò)對(duì)分布式電源的工作原理進(jìn)行分析,提出了廣泛應(yīng)用的逆變型分布式電源(Inverter-interfaced Distribution Generation,IIDG)的等值模型。建立了有源配電網(wǎng)的短路故障模型,對(duì)分布式電源接入對(duì)三段式電流的影響進(jìn)行定量分析,最終實(shí)現(xiàn)有源配電網(wǎng)的繼電保護(hù)的改進(jìn)方案,為配電網(wǎng)的可靠運(yùn)行提供保障。首先,詳細(xì)介紹了有源配電網(wǎng)的相關(guān)概念,并根據(jù)按并網(wǎng)方式將分布式電源分為逆變型、同步電機(jī)型和異步電機(jī)型電源。逆變型電源以良好控制及轉(zhuǎn)換電能的能力得到廣泛應(yīng)用,成為分布式電源最主要的電源形式。逆變型分布式電源的短路電流和逆變器的控制方式有關(guān),對(duì)配電網(wǎng)的影響分析更為復(fù)雜。分別對(duì)不同類型的分布式電源進(jìn)行了短路電流分析。其次,在我國(guó)并網(wǎng)規(guī)程對(duì)分布式電源低壓穿越功能的要求下,為了實(shí)現(xiàn)逆變型分布式電源的最優(yōu)工作效率,通過(guò)增加電壓跌落門檻值實(shí)現(xiàn)輸出有功電流的優(yōu)化,提出了基于無(wú)功電流支撐的低電壓控制策略。分析了采用該策略時(shí)逆變型分布式電源的故障特性,在此基礎(chǔ)上建立了含IIDG的配電網(wǎng)短路計(jì)算模型。DIGSILENT仿真表明該低電壓穿越策略在電壓跌落時(shí)可實(shí)現(xiàn)IIDG的并網(wǎng)運(yùn)行和最大的有功輸出。含IIDG的配電網(wǎng)短路計(jì)算模型考慮了低壓穿越策略,為大規(guī)模分布式電源并網(wǎng)的繼電保護(hù)方案提供參考。然后,分析了分布式電源接入后對(duì)配電網(wǎng)的影響,從DG容量和故障點(diǎn)位置等因素分別對(duì)流過(guò)保護(hù)的電流進(jìn)行分析比較。利用上文提出的基于低電壓穿越策略的IIDG故障等值模型,對(duì)有源配電網(wǎng)的瞬時(shí)電流速斷保護(hù)和限時(shí)電流速斷保護(hù)的整定方法進(jìn)行了改進(jìn)。針對(duì)過(guò)電流保護(hù)中逆變型分布式電源的短路電流較小不易識(shí)別的問(wèn)題,提出了基于電壓加速因子的過(guò)電流保護(hù)方案。此外,分析討論了環(huán)網(wǎng)運(yùn)行中過(guò)電流保護(hù)在近電源端延時(shí)過(guò)長(zhǎng),不利于系統(tǒng)穩(wěn)定的問(wèn)題,提出了故障線路兩端保護(hù)配合的加速動(dòng)作保護(hù)方案。在高滲透率的有源配電網(wǎng)仿真中證明上述保護(hù)方案能解決分布式電源接入后對(duì)配電網(wǎng)保護(hù)帶來(lái)的一系列問(wèn)題。
[Abstract]:The problem of energy and environmental pollution is becoming more and more serious all over the world. The traditional mode of centralized generation and long-distance transmission of power network has many problems, such as large power loss and poor stability of power supply. Distributed Generation (DGG) is characterized by its cleanness and flexibility. Tunability and other advantages are more and more widely used in distribution network. The access of distributed generation changes the unidirectional power supply mode of distribution network and influences the three-segment current protection of traditional distribution network. Based on the analysis of the working principle of distributed power generation, the equivalent model of Inverter-interfaced Distribution Generation (IIDG), which is widely used in inverters, is proposed in this paper. The short-circuit fault model of active distribution network is established, and the influence of distributed power supply access on three-section current is quantitatively analyzed. Finally, the improved scheme of relay protection of active distribution network is realized, which provides a guarantee for the reliable operation of distribution network. Firstly, the concept of active distribution network is introduced in detail, and the distributed power supply is divided into three types: inverter, synchronous motor and asynchronous motor according to the grid-connected mode. Inverter power supply is widely used for its ability to control and convert electric energy. It becomes the main power supply form of distributed power supply. The short circuit current of the inverter is related to the control mode of the inverter, and the analysis of the influence on the distribution network is more complicated. The short circuit current analysis of different types of distributed power supply is carried out. Secondly, under the requirement of the low voltage traversing function of the distributed power supply in our country, in order to realize the optimal working efficiency of the inverter distributed power supply, the output active power current is optimized by increasing the voltage drop threshold. A low voltage control strategy based on reactive current support is proposed. The fault characteristics of inverter distributed power supply with this strategy are analyzed. On this basis, the short circuit calculation model of distribution network with IIDG. DIGSILENT simulation shows that the low voltage traversing strategy can realize the grid-connected operation and the maximum active power output of IIDG when the voltage drops. Low-voltage traversing strategy is considered in the short-circuit calculation model of distribution network with IIDG, which provides a reference for large-scale distributed power generation relay protection scheme. Then, the influence of DG on distribution network is analyzed, and the current of protection is analyzed and compared from DG capacity and fault point location. Using the IIDG fault equivalent model based on low voltage traversing strategy proposed above, the tuning methods of instantaneous current quick break protection and limited time current quick break protection for active distribution network are improved. In order to solve the problem that the short-circuit current of inverter distributed power supply is small and difficult to identify in over-current protection, an overcurrent protection scheme based on voltage acceleration factor is proposed. In addition, this paper analyzes and discusses the problem that the over-current protection delay is too long in the near power source during the operation of the ring network, which is not conducive to the stability of the system, and puts forward the accelerated action protection scheme for the cooperation of the protection at both ends of the fault line. In the simulation of the active distribution network with high permeability, it is proved that the above protection scheme can solve a series of problems caused by the distribution network protection after the distributed power supply is connected.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM77

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本文編號(hào)：1983473