Study of the 34,5 kV Network Voltage Quality During the Parallel Operation of an Electric Arc Furnace and Rolling Mill Electric Drives

The work carried out research on the frequency response of the 34.5 kV network of the metallurgical plant MMK Metalurji, Iskenderun, Turkey during the parallel operation of the rolling and electric steel-making complexes. A comprehensive simulation model of an arc steelmaking furnace, electric drives of a rolling mill and an in-plant network of 34,5 kV has been developed. In the simulation, the experimentally obtained instantaneous values of the currents consumed by the equipment of the electric steel-making and rolling complexes were used. The results of modeling the frequency response of a 34,5 kV network with parallel operation of two complexes were presented. The problem of the influence of resonance phenomena in the frequency response of the 34,5 kV network on the voltage quality during the parallel operation of the electric steel-making and rolling complexes was revealed. A method was proposed for shifting the resonance to the safe region of the frequency response, where there are no significant harmonics generated by active rectifiers. Thanks to the application of this method, an improvement in the harmonic composition of the voltage across the 34,5 kV busbar section is achieved.