Ingeteam Improves DFIG’s Fault Ride Through Behavior with Crowbarless Solution
Ingeteam announced today the introduction of its Crowbarless solution, a modular Fault Ride Through (FRT) system for power converters that will strengthen the grid compliance of Doubly fed induction generators (DFIG). Thanks to the modular FRT system, the Crowbarless solution offers superior capabilities compared to the active crowbar system traditionally used to protect the power converter from grid voltage transient.
Until recently, most grid codes allowed wind turbines to disconnect from the grid when transients in grid voltage could jeopardize the integrity of their elements, especially the power converter. Due to the ever-increasing wind power penetration around the world, this is no longer the case. Ingeteam has come up with a new way to deal with low capacity transmission lines (so-called weak grids) and fault-ride through events, to remain fully grid compliant.
“The traditional crowbar solution used in DFIG topology presents a poor response to the voltage sags. This is because, when a voltage sags appears in the stator terminal, the machine side converter is disabled until the inductor generator flux is stabilized. Thanks to new software and hardware implemented in our crowbarless solution, the machine side converter is available at all times during the voltage sag, achieving injection times required by the most restrictive grid codes,” commented Ingeteam’s R&D Director Carlos Gironés.
To date, the most widely used system to protect the power converters from voltage spikes is the so-called “active crowbar”, a shunt circuit composed of actively controlled switches and dissipation elements which are connected in order to shunt the high currents, avoiding damages to the converter. This system, however, presents the limitation that while the active crowbar is connected, the power converter is not in operation, the active and reactive power set points cannot be tracked, and therefore the wind turbine is not being controlled. Ingeteam’s Crowbarless power converter, designed to operate in DFIG topology, uses a Modular FRT system that removes the need for the active crowbar.
The Crowbarless solution presents behavioral advantages in issues related to weak grids or grid fault events, allowing Doubly fed induction generators to overcome previous technical constraints and hence comply with the strictest grid codes (like the German FGW). Coupled to a suitable selection of grid filter and control loops tuning, it is able to keep the control of the wind turbine during these transients, achieving the controllability required in order to operate in weak grids.
In addition, the modularity concept of the FRT system allows for a cost optimization for each application. The solution is very flexible and offers a cost-optimal power converter option for each wind farm scenario.
The expertise of Ingeteam on the matter has been recognized by the American Wind Energy Association (AWEA), the national trade association for the US wind industry. Aritz Lorea, DFIG Product Manager at Ingeteam Wind Energy, will be speaking on the subject on Tuesday, May 24 (1:00 PM, Room: Tech Station) at AWEA WINDPOWER 2016 in New Orleans.
