光伏系统直流故障电弧特性与检测装置研究

Research on DC Arc Fault Characteristics and Detection Device in Photovoltaic System

为避免故障电弧造成的危害,概述了国内外直流故障电弧相关标准及检测方法、产品,并分析方法及产品优缺点。讨论了光伏阵列时变性、逆变器开关噪声等系统因素对故障电弧检测的干扰,基于MATLAB仿真平台研究了故障电弧特性,利用时频变换方法提取特征,获取特征量。最终以研制的一款工程样机在额定电压375 V场景中进行测试。为明确检测算法是否能避免开关噪声的干扰,在DC/DC故障电弧、逆变器负载故障电弧、逆变器负载正常启动3种条件下进行测试,结果表明所研制样机具有快速、准确切除故障的良好性能,切断故障所需时间约0.85 s,符合UL 1699B标准。

In order to avoid hazards caused by arc faults,the relevant standards,detection methods and products proposed at home and abroad are overviewed,and the advantages and disadvantages of these detection methods and products are analyzed.The interferences of arc fault detection are discussed,which are caused by the system factors such as the time change property of the PV array and the inverter switch noise.Based on MATLAB simulation platform,the DC arc fault characteristics are discussed.The features are extracted by time-frequency transformation method,and the feature quantities are obtained.Finally,a product prototype is developed,which is tested in the application scenario with 375 V voltage.In order to check whether the designed arc fault detection algorithm can better avoid the interference of switching noise,the test is carried out under three conditions:DC/DC arc fault,inverter load arc fault,and inverter load normal startup.The results show that the developed prototype is able to cut faults accurately and quickly.The time required to cut off the faults is about 0.85 s,which meet UL1699B standard.