Modelling and experimentation of grid-forming inverters for standalone hybrid wind-battery systems

This paper presents a methodology to model and develop a standalone hybrid wind-battery system in the laboratory environment to reduce experimentation cost, which would otherwise be costly in the field. A full-scale system is established using off-the-shelf components. The development time is expedited using this approach. In addition, it is believed that a full-scale system in the laboratory presents a more controlled test environment and its performance is close to the real system. The steady-state and dynamic analysis of a standalone hybrid wind-battery system are presented, from both a modelling and an experimental perspective. Three single-phase grid-forming inverters and a fixed speed wind turbine are used as a platform for case studies. The grid-forming inverters adopt droop control method which allows parallel operation of several grid-forming sources. Droop control-based inverters are known as independent and autonomous due to the elimination of intercommunication links among distributed converters. Moreover, the adopted fixed speed wind turbine employs a squirrel cage induction generator which is well known for its robustness, high reliability, simple operation and low maintenance. The simplicity and robustness of these selected components minimise the problems faced by the remote communities where technical assistance is limited. The results show a good correlation between the modelling, the experimental measurements, and the field tested results.