Large induction motors draw starting currents of 5 to 7 times their rated full-load current during direct-on-line (DOL) energisation, producing significant transient voltage depression at the point of common coupling (PCC) that can disrupt adjacent loads, trigger contactor dropout, and in high-impedance networks, cause complete motor stalling. Accurate prediction of this dynamic behaviour is essential for safe and reliable industrial power system design, yet conventional hand calculation methods based on static equivalent circuit models are demonstrably insufficient for capturing the full complexity of the motor starting transient.

This paper presents a comprehensive case study of motor acceleration analysis conducted on the ETAP webinar industrial network using ETAP software version 20.0.1. The study system is based on the 13.8 kV Sub2A/Sub2B network, the 4.16 kV Sub 3 bus, transformers T1 and T2, synchronous motor Syn1 rated at 1250 HP, induction motor Mtr2 rated at 2500 HP and 13.2 kV, and capacitor bank CAP1 rated at 3 x 0.15 Mvar. The analysis uses the real ETAP readings visible in the screenshots, including motor nameplate data, locked-rotor values, voltage dip readings, speed/current plots, transient stability results, and Motor Starting Analyzer output.