Effects review on transformer and line impedance by X/R ratio in power system

Impedance on transformers and transmission lines (T/L) in power system has different values per rated voltage and capacity, and in general, grid operators and plant designer have used reference data in the IEEE C37.010 standard or design specification data of designer. Therefore impedance values (zero, positive and negative impedance) of transformer and T/L have been obtaining by maker's data sheet per voltages and capacity, and power grid setup using calculated X/R value may help to economic operation of power system using data, which related to voltage regulation, and power loss, and optimum power system. This paper proposed to the proper impedance, these results may help to ensure reliability of power quality in smart grid and plant.