Steady-state analysis of electric spring for smart grid

This paper provides an analyses on the steady-state of electric spring (ES) for stabilizing future smart grid with intermittent renewable energy sources. The objectives of this work are to reveal the working principle of ES for providing voltage support to the power grid, and to provide theoretical basis for the design of ES. This work is focused on the steady-state characteristics of ES. With respect to the phase angle of non-critical load current changing from -90° to 90°, the effective operating range, change of power factor, and variation of phase angle δ used in δ control implement, are analyzed in detail basing on the vector diagram model of ES. Lastly, three studies are carried out to validate the voltage boosting and reduction functions of ES in stabilizing the fluctuant voltage, as well as the effective operating range of ES. The analysis provides guidelines for the distributions of ESs in the distributed systems.