Abstract-The smart transformer, a solid-state transformer with control and communication functionalities should provide services to the grid. This paper proposes to use a different frequency respect to the fundamental frequency, to provide such services to the distribution grid. The approach has the main benefit to transfer energy from point to point of the grid, exploiting the lower impedance path that multi-frequency converters offer. This paper describes the control strategy of the multi-frequency converters, and verifies their impact on distribution grid.
Intermittent generation and load demand are one of the major challenges for grid operators. Caused for example by renewables power variability or electric vehicle charging, it can create mismatches between the realtime and forecasted demand, affecting frequency regulation. To alleviate this mismatch, operators have to resort either on the balancing market or on extensive use of energy storage systems, which increases operation costs. This paper introduces a load levelling approach exploiting the voltage dependency of the loads. With a controlled reactive power injection, the converters of fast charging stations can influence the voltage profile, and consequently the power consumption of voltage-dependent loads. The approach has two main goals: minimizing the mismatch with respect to the demand forecast and reducing grid losses. Fast charging stations are particularly suited for this approach. Being employed with full capacity for charging only for short-time, their spare capacity can be exploited to apply the load levelling approach. This proposed approach is discussed theoretically and analyzed in a modified distribution network in Northern Germany. Parameters variation analysis has been performed to thoroughly demonstrate the effectiveness of the approach under different load/grid conditions. Its feasibility has been evaluated by means of power-hardware-in-the-loop tests.
Abstract-Smart grids have attracted the attention of the scientific community for years, since the ability to better manage distributed resources in a dynamic grid scenario is of paramount importance. Among the solutions that have been investigated, there is the smart transformer (ST) distribution concept, where an AC/AC power converter substitutes the traditional distribution transformer while enabling additional services. Considering that the ST can generate arbitrary voltage waveforms, power distribution is not restricted anymore to the fundamental frequency, but additional harmonics can be used. This paper analyzes different control possibilities for multi-frequency converters, comparing the results in terms of dynamic performance, control complexity, and communication requirements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.