Development of improved direct current based saturated core fault current limiter in DFIG system for enhancing the low voltage ride-through capability

With the increase of electrical energy consumption and associated power grid expansion the complexity in the grid network increases which tends to increase the fault occurrence possibilities. Low voltage ride-through capability helps the system to achieve the standard of grid code by remaining connected with the grid during fault occurrence. Direct current-based saturated core fault current limiter (DC-SCFCL) is a type of fault current limiter with superior influence in fault ride-through (FRT) capability. It has an arrangement of embedded alternating current coil and direct current (DC) coil across the side and centre of the core limb. However, being more effective in FRT, the ideal DC-SCFCL has some of its drawback such as development of high voltage across the DC coil and more current difference during fault occurrence. To limit these drawbacks a modified DC-SCFCL with shorted ring and also working with the coil below its critical temperature has been proposed in this study. The voltage profile, as well as the current profile, has been analysed which comprises its behaviour in all conditions. The proposed technique is applied to DFIG-based wind energy system to restrict the fault current and enhance the FRT capability.