Voltage Control of Large-Scale Distribution Systems during Wind Speed Transients Using SMES

This paper discusses the application of superconducting magnetic energy storage (SMES) for voltage control of large-scale distribution systems during wind speed transients. The wind turbine adopted in this paper is the squirrel cage induction generator (SCIG) with a parallel connected capacitor bank for reactive power support and the adopted distribution system is the 90-bus radial distribution system. This type of wind turbine is the worst type from the point of view of voltage control and is selected to prove the effectiveness of the proposed control strategy of SMES active and reactive powers on the voltage profile of all buses of the distribution system. Moreover, one of the worst scenarios of wind transient is studied in this paper. Wind energy generation system (WEGS) and SMES are connected at the same bus for better improvement of voltage profile. SMES coil is immersed in a cooling liquid to keep it in the superconducting state, the voltage across the coil is stepped down by transformer and the flow of SMES power is controlled by fuzzy logic controller (FLC). FLC is designed so that SMES can charge/discharge real power depending on the wind speed. Moreover, value of reactive power delivered from the SMES to the distribution system is controlled according to the magnitude of bus voltage. FLC is designed with two inputs; deviation in wind speed and variations in SMES current. The obtained results validated the adopted control technique to improve the voltage profile of all buses of the studied system.