| 引用本文: | 吕干云,吴启宇,吴晨媛,程浩忠,时翔.基于双向谐波电压变动的光伏并网孤岛检测[J].电力自动化设备,2019,39(3): |
| Lü Ganyun,WU Qiyu,WU Chenyuan,CHENG Haozhong,SHI Xiang.Islanding detection of grid-connected PV system based on bi-direction voltage harmonic variation[J].Electric Power Automation Equipment,2019,39(3): |
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| 摘要: |
| 针对传统的被动式光伏并网孤岛检测存在的检测死区问题，提出一种基于双向谐波电压变化量的光伏并网孤岛检测方法。通过分析孤岛前后谐波电压的变动及传统谐波电压检测法的失效机理，提出基于双向谐波电压的孤岛检测策略。利用加窗傅里叶变换同步计算光伏集中并网发电系统送出线路电流及所接母线电压的谐波，从而获得各次谐波功率；由并网运行时谐波功率的正负极性判断各次谐波源方向，并根据正、负最大谐波功率值选择系统侧、光伏侧谐波的特征频次；利用滑动加窗傅里叶变换分析这2个频次的母线谐波电压变化量，建立孤岛检测判据，若系统侧谐波电压减小量和光伏侧谐波电压增加量均满足判据，则发生孤岛。仿真结果验证了所提方法的有效性。该方法不影响并网逆变器输出的电能质量，且能在较严重背景谐波下有效检测孤岛，检测死区较小。 |
| 关键词: 光伏并网系统 孤岛检测 双向谐波 谐波电压变动 |
| DOI：10.16081/j.issn.1006-6047.2019.03.031 |
| 分类号:TM615 |
| 基金项目:国家自然科学基金资助项目(51577086)；电力传输与功率变换控制教育部重点实验室开放课题(2016AA02)；江苏“六大人才高峰”项目；江苏高校“青蓝工程”项目 |
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| Islanding detection of grid-connected PV system based on bi-direction voltage harmonic variation |
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Lü Ganyun1, WU Qiyu1, WU Chenyuan1, CHENG Haozhong2, SHI Xiang3
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1.School of Electric Power Engineering, Nanjing Institute of Technology, Nanjing 211167, China;2.Key Laboratory of Control of Power Transmission and Conversion, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China;3.State Grid Qingdao Power Supply Company, Qingdao 266002, China
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| Abstract: |
| Aiming at the non-detection zone problem of traditional passive islanding detection for grid-connected PV(PhotoVoltaic) system, a detection method based on bi-direction voltage harmonic variation is proposed. With the analysis of voltage harmonic variation before and after islanding and failure mechanism of traditional voltage harmonic detection method, an islanding detection strategy based on bi-direction voltage harmonic is proposed. The windowed Fourier transform is used to calculate the harmonics of outgoing line current and bus voltage in centralized grid-connected PV system, and thus the harmonic power is obtained. The direction of each harmonic source is determined by the positive or negative polarity of harmonic power in grid-connected operation, and the characteristic orders of harmonic at system side and PV side are selected according to the maximum positive and negative harmonic power values. The sliding windowed Fourier transform is adopted to analyze bus voltage harmonic variation of the two orders, and the islanding detection criteria is established. If the reduction of voltage harmonic at system side and the increment at PV side both meet the criteria, there is an island. Simulative results verify the effectiveness of the proposed method. The method does not affect the output power quality of grid-connected inverters, and can effectively detect islands under serious background harmonics with a small non-detection zone. |
| Key words: grid-connected PV system islanding detection bi-direction harmonic voltage harmonic variation |
