Aggregation of multiple inverter-based harmonic sources within a renewable energy generation plant

This paper provides an overview of the work undertaken investigating the aggregation of multiple identical harmonic sources within a single renewable energy generator (REG) plant. Common practice when undertaking harmonic analysis of REG plants in Australia is to assume that the harmonic emissions of identical equipment, e.g. wind/solar PV inverters, have no significant diversity between sources for all harmonic orders, i.e. the emissions at each harmonic order add arithmetically. The results presented in this paper suggest significant diversity to exist across all harmonic orders within a large wind-based REG plant for significant periods of time. This was determined through analysis of measurements captured within a large wind farm operating in the Australian power system. Such outcomes are important as overly pessimistic assumptions in relation to the aggregation of harmonic sources are capable of increasing the likelihood of mitigation being required. This is also capable of impacting the design process of the mitigation solution.