Islanding detection method of multi‐port photovoltaic DC micro grid based on harmonic impedance measurement. Issue 14 (3rd October 2019)

• Record Type: Journal Article
• Authors: Ke, Jia; Zhengxuan, Zhu; Qijuan, Zhao; Zhe, Yang; Tianshu, Bi
• Is Part Of: IET renewable power generation. Volume 13:Issue 14(2019)
• Page Start: 2604
• Page End: 2611
• Publication Date: 2019-10-03
• Subjects: DC‐DC power convertors -- power system harmonics -- photovoltaic power systems -- reactive power -- power grids -- distributed power generation -- electric impedance measurement -- power system measurement -- synchronisation -- failure analysis -- power generation reliability -- power supply quality; islanding detection method -- multiport photovoltaic DC microgrid -- harmonic impedance measurement -- DC network -- active power injection methods -- multiple photovoltaic sources -- detection failure -- impedance measurement IDM -- power quality -- disturbance intensity -- injection signal synchronization -- DC systems -- PV sources -- DC‐DC converters -- electrical quantities -- transmit reactive power -- harmonic injection -- islanding operation state -- power electronic devices -- high‐frequency impedance model -- multiPV DC microgrid; Renewable energy sources -- Periodicals; 333.79405
• DOI: 10.1049/iet-rpg.2019.0271
• Languages: English
• ISSNs: 1752-1416

Abstract

Abstract : DC Grid does not transmit reactive power, nor does it offer frequency and phase issues. This results in malfunction of conventional islanding detection methods (IDMs) that rely on the above quantities. At present, the DC IDMs proposed in literatures are mostly active power injection methods based on DC/DC converters. However, in a multi‐photovoltaic (PV) DC system, the synchronization of the injection of converters is difficult to guarantee, which may lead to detection failure. This paper proposes an impedance measurement IDM for multi‐PV DC micro grid based on the analysis of high‐frequency impedance model of power electronic devices. The impedance of DC converters is constant at high frequency and the harmonic impedance of the system changes significantly after islanding, so that islanding operation can be accurately detected. The harmonic impedance change directly reflects the structural changes of the system, and its calculation requires less disturbance intensity, which avoids the requirement of synchronous injection. Therefore, the method uses a DC/DC converter for injection, without the need for additional injection equipment. The method has little influence on power quality and theoretically has no none detection zone. Simulation results show that the method can perform accurately islanding detection in multi‐PV DC micro grid.