Prof. Dr. Ruy Alberto Pisani Altafim, presenting a collaborative work with the University of São Paulo at the 2017 Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), in Fort Worth Texas/USA. The work Detection of acoustic emissions from partial discharges in distribution transformers with piezoelectret transducers, discuss the possibility of detecting partial discharges inside distribution transformers filled with oil using piezoelectret-based sensors. The advantages of the proposed transducer is their reduced cost compared to regular acustic systems.