Study of AC contactors during voltage sags

This paper proposes a model for the dynamic analysis of AC contactors. The model equations are presented and the implementation of the calculation algorithm is discussed. The high calculation speed of the implemented algorithm allows an extensive set of voltage sags to be studied, and their impact on the contactor performance to be analyzed. The contactor sensitivity CBEMA curves are obtained for different initial voltage phases at the voltage drop point. In particular, the CBEMA curve for 90° of initial voltage phase (i.e. when the voltage at the start of the sag is zero) is studied and justified.