Case studies on large PV plants: Harmonic distortion, unbalance and their effects

Some case studies on PV systems are reported with reference to harmonic distortion, unbalance and their effects on protection systems. The experiences are related to: i) laboratory experiments made on commercial LV inverters aimed to study their harmonic impact; ii) harmonics produced by an existing PV plant both at lower and higher frequencies; iii) voltage unbalances caused by high penetration of single-phase connected PV sources; and, finally, iv) untimely tripping of protection systems of overhead lines fed by large PV plants.