Enhancing LVRT of DFIG by Using a Superconducting Current Limiter on Rotor Circuit

Abstract

This paper have studied the dynamic of a 2.0 MW Doubly Fed Induction Generator (DFIG) during a severe voltage sag. Using the dynamic model of a DFIG, it was possible to determine the current, Electromagnetic Force and flux behavior during three-phase symmetrical voltage dip. Among the technologies of wind turbines the DFIG is widely employed; however, this machine is extremely susceptible to disturbances from the grid. In order to improve DFIG Low Voltage Ride-Through (LVRT), it is proposed a novel solution, using Superconducting Current Limiter (SCL) in two arrangements: one, the SCL is placed between the machine rotor and the rotor side converter (RSC), and another placed in the RSC DC-link. The proposal is validated through simulation using PSCAD TM /EMTDC TM and according to requirements of specific regulations. The analysis ensure that both SCL arrangements behave likewise, and are effective in decrement the rotor currents during the disturbance.

Technical Evaluation of Superconducting Fault Current Limiters Used in a Micro-Grid by Considering the Fault Characteristics of Distributed Generation, Energy Storage and Power Loads

“…Since the SFCL parameters are respectively set as L 1 = 50 mH and R sc = 10 Ω, L 1 = 70 mH and R sc = 30 Ω, L 1 = 90 mH and R sc = 50 Ω, the fault current's peak value can be respectively suppressed to 180 A, 117 A, 89 A, and the current-limiting ratio is about 75.7%, 84.2%, 88%. Figures [16][17][18][19] show the DG voltage, exchange power and frequency fluctuations of the micro-grid system under the internal fault. From these figures, the positive effects of the two SFCLs can be observed.…”

“…Since the power Load 1 is shorted, the decrease of the exchange power and the full utilization of the local DG units can help to achieve the power balance. In addition, taking the enhancement of the micro-grid's frequency stability as an example, employing the SFCLs can make Figures [16][17][18][19] show the DG voltage, exchange power and frequency fluctuations of the micro-grid system under the internal fault. From these figures, the positive effects of the two SFCLs can be observed.…”

“…There are many remarkable merits, including: sub-cycle operation in response to faults; reduced damage at the point of fault; and critical protection of relevant power equipment [14][15][16][17][18][19]. Currently, some basic research works have been done to promote the application of one or more SFCLs in a micro-grid.…”

Transient behavior representation, contribution to fault current assessment, and transient response improvement in DFIG-based wind turbines assisted with crowbar hardware

“…Approaches proposed in literatures for the LVRT capability enhancement of DFIGs are divided into 2 main groups: LVRT improvement by adding external hardware [5][6][7][8][9][10][11][12][13][14][15][16][17] and LVRT enhancement by using advanced control methods and modifying the DFIG converter control. [18][19][20][21][22][23][24][25][26] The first group of LVRT approaches uses external passive and active equipments and hardware.…”

Passivity-Based Control of a Doubly Fed Induction Generator System under Unbalanced Grid Voltage Conditions

“…Among these technologies, the doubly fed induction generator (DFIG) system has been adopted in a large proportion of wind turbines, with benefits of small volume, low cost, and stable operation performance [3][4][5].…”