Power quality assessment of large motor starting and loading for the integrated steel-making cogeneration facility

This paper presents the power quality assessment of large synchronous motor starting and loading in the integrated steel-making cogeneration facility. To execute the transient stability analysis, the proper mathematical models and the accurate parameters of the cogeneration units, excitation systems, governor systems, load and static VAr compensators (SVC) are investigated in detail. Four study cases with or without considering the connection of the power grid, the installation of autotransformer starter and SVC are performed to demonstrate the dynamic responses of system frequency, voltage and cogeneration units due to motor starting and loading. Also, the voltage sag ride-through curve of sensitivity load has been included and a power quality index (PQI) due to voltage variation in the assessment period has been proposed to find the impact of motor starting and loading on the power quality of the cogeneration system. It is concluded that the system dynamic responses and PQI values have better performances if the autotransformer starter is applied with either the regulation of SVC system or connecting to the bulk power grid.