Control and analysis of anti-islanding protection techniques for grid-connected photovoltaic systems

Abstract

This thesis presents a comparative study of anti-islanding detection techniques for Photovoltaic (PV) systems which also includes energy policy review and the related standards. The studied anti-islanding detection includes passive, active and a proposed hybrid technique. The proposed hybrid anti-islanding detection technique combines both active and passive detection techniques, namely Voltage Frequency Protection (VFP) and Active Frequency Drift (AFD). The passive technique is used as a primary protection, whereas the active technique is activated when an islanding situation is suspected by the passive technique. The studied anti-islanding techniques are simulated using MATLAB/Simulink simulation package. The results of simulation show that the proposed hybrid anti-islanding detection technique is able to achieve higher detection efficiency as compared to the single detection technique. The proposed technique is able to detect without having the problem as occurred to the VFP while it gains at least 50% improvement of total harmonics distortion (THD) than the AFD. In addition to that, other improvements such as, a narrower non-detected zone (NDZ), faster response time and better power quality are achieved compared to single detection technique. Besides that, the standard compliance of grid-connected PV system is reviewed as it is significant for the PV grid interconnection and distribution generation. The PV grid interconnection standards specify the criteria in utility interface and islanding prevention, in order to fulfil the requirement of MS IEC 61727:2010 and MS IEC 62116:2010 in Malaysia. Lastly, the Malaysian government's efforts in reconstructing the energy policies to promote PV are also reviewed. This study reveals that proper execution and support from local community to international level, financial aids or subsidies, technical support after installation, and PV policies and promotion plans are essential in making the PV systems development a success.