One of the most important parameters of the system where wind turbine generators (WTGs) are connected is voltage profile at the point of common coupling (PCC). In the earlier stage, WTGs were possible to be disconnected from the system to avoid the damage of WTGs. Following the rapid injection of WTGs to the existing network during last decades, the transmission line operators (TSOs) require WTGs to stay connected in certain level of fault to continue support the grid. This new requirements have been compiled in new international grid codes. In this paper, superconducting magnetic energy storage (SMES) is applied to improve the voltage profile of PCC bus where WTGs equipped with doubly fed induction generator (DFIG) is connected to meet the used gird codes of Spain and German during grid dip and swell. The voltage dip at the grid side is examined to comply with the low voltage ride through (LVRT) while the voltage swell at the grid side is examined to comply with the high voltage ride through (HVRT) of both Spain and German voltage ride through (VRT).
In this paper, a travelling wave electroabsorption modulators (TWEAMs) based on asymmetric intra-step-barrier coupled double strained quantum wells (AICD-SQW) active layer is designed and analyzed at 1.55 μm for the first time. The AICD-SQW structure has advantages such as very low insertion loss, zero chirp, large Stark shift and high extinction ratio in comparison with the intra-step quantum well (IQW) structure. For this purpose, the influence of the electrode width and ground metal separation on their transmission line microwave properties (microwave index, microwave loss, and characteristic impedance) and modulation bandwidth are analyzed.