Development of a Model for Calculation of Energy Absorbed by a ZnO Surge Arrester During Transients

Several models were successfully developed to reproduce the dynamic behavior of ZnO surge arrester, but the accuracy and reliability of these models are only evaluated for residual voltage calculations. This paper presents a model developed with the specific goal of achieving reliable and accurate modeling of the energy absorbed by a ZnO surge arrester during impulsive transients. To develop and test the model, an experimental database was built, composed of responses of ZnO varistors to current impulses. The database contains the response of varistors of different classes and manufacturers, subjected to current impulses with different waveforms and amplitudes. Then, using system identification techniques, a mathematical model was proposed and validated. The proposed model was successfully tested on the same circumstances that traditional models are used and its performance was compared with the most relevant existing ZnO model. The results indicate that the developed model is an overall valid model for ZnO surge arresters and that energy calculations performed with it are more accurate and reliable.