The main aim of this paper reviews the issue of an energy-efficiency improvement of an industrial grid via reversible medium voltage AC drives based on three level neutral point clamped (3L-NPC) active front-end (AFE) rectifiers. 18-pulse connection circuit of the reversible AC drive has been considered. 18-pulse circuit comprises three power transformers connecting in parallel with the secondary winding voltages phase shifts. Pulse width modulation selective harmonic elimination (PWMSHE) method was used for the 3L-NPC AFE rectifiers. Mathematical descriptions for a 3L-NPC converter, the PWMSHE method with eliminating of the 17th, 19th and 17th, 19th, 35th, 37th harmonics, and a system "Reversible medium voltage AC drives based on 3L-NPC AFE rectifiers - industrial grid" are provided. Twelvemegawatt AC main electric drive of a plate mill rolling stand was used as a study object. Mathematical research of the energy-efficiency improvement of the industrial grid by the electric drive have been simulated using Matlab/Simulink program. Experimental research of operating conditionals of the main electric drive were carried out at the difficult-to-form steel grade in the range of a roughing and a finish rolling. It has allowed us to calculate the magnitudes of active, reactive, and apparent power magnitudes and determine a possibility of power factor correction in industrial grid via at the roughing.