Design of Capacitive Bridge Fault Current Limiter for Low-Voltage Ride-Through Capacity Enrichment of Doubly Fed Induction Generator-Based Wind Farm

Abstract

The increase in penetration of wind farms operating with doubly fed induction generators (DFIG) results in stability issues such as voltage dips and high short circuit currents in the case of faults. To overcome these issues, and to achieve reliable and sustainable power from an uncertain wind source, fault current limiters (FCL) are incorporated. This work focuses on limiting the short circuit current level and fulfilling the reactive power compensation of a DFIG wind farm using a capacitive bridge fault current limiter (CBFCL). To deliver sustainable wind power to the grid, a fuzzy-based CBFCL is designed for generating optimal reactive power to suppress the instantaneous voltage drop during the fault and in the recovery state. The performance of the proposed fuzzy-based CBFCL is presented under a fault condition to account for real-time conditions. The results show that the proposed fuzzy-based CBFCL offers a more effective solution for overcoming the low voltage ride through (LVRT) problem than a traditional controller.

Improved Transient Performance of a DFIG-Based Wind-Power System Using the Combined Control of Active Crowbars

“…The proposed controls efficiently reduce the oscillations of the generator torque, as demonstrated in Figure 6c. Moreover, as seen in Figure 6d, the DC-link voltage fluctuations do not exceed 15% of the rated value, indicating that it remains consistent within limits (25). Similarly, once the fault is cleared, the DC-link voltage drops by no more than 5% of its rated value for a few milliseconds before returning to its rated value.…”

“…A combination of active crowbars installed at the rotor side and DC-link was designed and implemented to mitigate the impacts of the grid faults that can destroy the DC-link capacitor and cause massive current stresses on wind-power converters. The results showed that this crowbar combination efficiently controlled the transient rotor and stator currents as well as DC-link voltage variations within permitted limits (25), which were considered the criteria for successful LVRT implementation. Moreover, the electromagnetic torque oscillations were effectively suppressed.…”

“…To satisfy the aforementioned requirements (25) for LVRT, a combination of an active crowbar at the rotor-side and another parallel to the DC-link is proposed and implemented, which is presented in the next subsections. An active crowbar is capable of eliminating the short circuit and allows the device to function normally again when the transient is finished.…”

“…Modern WTs mostly include assisting hardware, such as crowbar protection [8,21,22], to mitigate DC-link voltage variations. Presently, the application of fault-current limiters (FCLs), such as an inductive bridge-type FCL [23] and a capacitive bridge-type FCL [5,[24][25][26], has attracted special attention as a potential solution for LVRT enhancement. Other hardware applications, such as a STATCOM [27], an energy storage device (ESD) [22,28], and a dynamic voltage restorer [29], have also been recommended.…”

Protecting DFIG‐based multi‐machine power system under transient‐state by nonlinear adaptive backstepping controller‐based capacitive BFCL

“…Therefore, series dynamic braking resistors (SDBRs) [23,29,35], bridge type fault current limiters (BFCLs) along with resistive, inductive, and capacitive components [36,37], series resonance type FCL [34], as well as parallel resonance type FCL (PRFCL) [38] show superior performance in smoothing the different output parameters of DFIG-based WFs. Among all the other types of BFCLs, capacitive bridge type fault current limiter (CBFCL) has been one of the newest and more improved BFCL to improve the FRT by a significant margin [39][40][41]. Moreover, it provides commensurate reactive power needed to recover PCC voltage after fault occurrence, which none of the other BFCLs provides.…”