Practical tables for tolerance assessment of adjustable speed drives under voltage sag

The tolerance of adjustable speed drive (ASD) under voltage sag is important for users to select equipment and take mitigation methods. However, it is not easy for users to obtain the tolerance information of ASD. To address this issue, this paper proposes practical tables for tolerance assessment of ASD under voltage sag, providing a simpler and faster way for an approximate understanding of the tolerance of ASD. First, this paper proposes a calculation method for three trip characteristics to describe the tolerance of ASD. Second, this paper presents a voltage tolerance curve (VTC) assessment model based on the three trip characteristics, and the coordinate of the "knee point" of VTC can be assessed straightforwardly. Furthermore, the practical tables for tolerance assessment of ASD are formed based on the studies mentioned above. Users can obtain the tolerance of ASDs by looking up the table when they know several key parameters. Simulations tests verify the effectiveness of the calculation method and practical tables.