Protection Coordination And Anti-Islanding Control Of Grid-Connected PV Systems

The conventional radial power distribution systems were initially not designed to accommodate distribution generation (DG). For an effective penetration of PV systems on a large-scale into the current distribution network, considerable work to investigate the nature of incompatibility problems has been done and research is being carried out to develop successful integration strategies. This paper aims to address the radial networks’ protection system challenges after embedding photovoltaic generation sources, investigation on the impacts of high PV penetrations on protection systems of distribution networks and lastly make modification and implement proper protection coordination of the grid-tied PV systems with some emphasis on anti-islanding protection. To accomplish the above-mentioned objectives, a radial distribution network is modelled, simulated and protection settings validated. The PV generation system is designed and added to specific distribution feeders and steady-state results obtained. The results show that addition of DGs cause the system to lose its radial power flow. There is an increase in fault contribution hence causing maloperation such as protection coordination mismatch. An overall protection scheme is proposed based on the addition of DG’s and an efficient adaptive protection system for the distribution networks with a considerable penetration of dispersed generations implemented. For the islanded mode, relaying considerations are provided and implementation of anti-islanding techniques achieved. The impact study is performed which is compared with the existing protection scheme and necessary modifications done. The entire analysis is simulated on a real-time digital simulator (RTDS) and results displayed in a MATLAB environment.