發(fā)布時間：2018-02-24 19:08

  本文關(guān)鍵詞： 分布式發(fā)電系統(tǒng) 孤島現(xiàn)象 希爾伯特-黃變換 被動檢測法　出處：《哈爾濱理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：孤島(Islanding)現(xiàn)象是指當(dāng)電網(wǎng)系統(tǒng)失去傳統(tǒng)集中供電方式的支撐后，區(qū)域內(nèi)的本地負(fù)載功率由分布式發(fā)電系統(tǒng)供給的獨(dú)立運(yùn)行狀態(tài)。 孤島現(xiàn)象可能會引起二次重合閘，甚至對微電網(wǎng)系統(tǒng)、負(fù)載和供電系統(tǒng)帶來損壞。因此，為保證電力系統(tǒng)安全穩(wěn)定運(yùn)行，確保電能質(zhì)量，需要及時檢測出孤島狀態(tài)，并將分布式發(fā)電系統(tǒng)從公共耦合點(diǎn)(Point of commoncoupling，PCC)斷開或者優(yōu)化分布式發(fā)電系統(tǒng)的組合和供電模式繼續(xù)對負(fù)荷進(jìn)行供電。 微電網(wǎng)孤島現(xiàn)象的檢測是并網(wǎng)逆變器系統(tǒng)的重要功能之一，自動切斷或者重新優(yōu)化分布式發(fā)電系統(tǒng)的過程也是以孤島檢測為前提的，檢測性能的好壞直接影響設(shè)備的安全運(yùn)行以及微電網(wǎng)技術(shù)的推廣與應(yīng)用。本文總結(jié)現(xiàn)有微電網(wǎng)孤島檢測方法的基礎(chǔ)上，把時頻分析方法移植應(yīng)用在孤島檢測課題，提出基于希爾伯特-黃變換(Hilbert-Huang Transform，HHT)算法的被動檢測法。主要原理是通過對公共耦合點(diǎn)處電壓信號進(jìn)行微觀分量(微電網(wǎng)由并網(wǎng)到孤島切換過程中電壓信號高頻諧波分量)的提取和識別。主要依據(jù)是電能質(zhì)量在公共耦合點(diǎn)逆變器端和主網(wǎng)端不相等原理，隨著微電網(wǎng)并網(wǎng)狀態(tài)切換到孤島狀態(tài)的過程，電能質(zhì)量的諧波成分會更加凸顯。 具體方法實(shí)施首先是PPC點(diǎn)電壓信號經(jīng)驗(yàn)?zāi)�態(tài)分解(Empirical ModeDecomposition，EMD)和Hilbert變換，然后是計(jì)算奇異點(diǎn)的位置坐標(biāo)，確定孤島現(xiàn)象產(chǎn)生時刻。應(yīng)用PSCAD/EMTDC和MATLAB/SIMULINK軟件，仿真光伏分布式發(fā)電系統(tǒng)，實(shí)現(xiàn)并網(wǎng)運(yùn)行與孤島運(yùn)行的平滑切換。人為設(shè)定多種試驗(yàn)條件下，例如，電網(wǎng)電壓暫降，多類型負(fù)載運(yùn)行、負(fù)荷的投切等，最終仿真的結(jié)果驗(yàn)證了HHT算法應(yīng)用于微電網(wǎng)孤島檢測問題的有效性與準(zhǔn)確性，，能夠迅速檢測到孤島現(xiàn)象。
[Abstract]:The phenomenon of islanding refers to the independent operation state of the local load power in the region provided by the distributed generation system when the power system loses the support of the traditional centralized power supply mode. The phenomenon of isolated island may cause secondary reclosing, even damage to microgrid system, load and power supply system. Therefore, in order to ensure the safe and stable operation of power system and ensure the power quality, it is necessary to detect the isolated island state in time. The distributed generation system is disconnected or optimized from the point of common coupling point of common coupling PCCs and the power supply mode of the distributed generation system continues to supply the load. The detection of islanding phenomenon in microgrid is one of the important functions of grid-connected inverter system. The process of automatically cutting off or reoptimizing distributed generation system is also based on islanding detection. The detection performance directly affects the safe operation of the equipment and the popularization and application of microgrid technology. Based on the summary of the existing detection methods of isolated islands in microgrid, the time-frequency analysis method is transplanted to the islanding detection subject. A passive detection method based on Hilbert-Huang transform HHT (Hilbert-Huang transform) algorithm is proposed in this paper. The main principle is to carry out the micro-component of voltage signal at common coupling point (high frequency harmonics of voltage signal in the process of switching from grid-connected to islanding in microgrid). Is based on the principle that the power quality is unequal between the inverter and the main network at the common coupling point. The harmonic components of power quality will become more prominent with the process of switching to the isolated island state in the grid-connected state of microgrid. Firstly, empirical mode decomposition (EMD) and Hilbert transform of PPC point voltage signal are implemented, then the position coordinates of singular points are calculated, and the time of island phenomenon is determined. Using PSCAD/EMTDC and MATLAB/SIMULINK software, the distributed photovoltaic generation system is simulated. Realize smooth switching between grid-connected operation and islanding operation. Under a variety of artificial test conditions, such as voltage sag, multi-type load operation, load switching and so on, Finally, the simulation results verify the validity and accuracy of the HHT algorithm applied to the detection of isolated islands in microgrid, and the phenomenon of isolated islands can be detected quickly.
【學(xué)位授予單位】：哈爾濱理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM732

【引證文獻(xiàn)】

相關(guān)期刊論文 前1條

1 何慧云;張春;陳林;;希爾伯特-黃變換在微電網(wǎng)故障定位中的應(yīng)用[J];南陽理工學(xué)院學(xué)報(bào);2016年02期

本文編號：1531369