ABSTRACT:
To
enhance the stability of a micro-grid under fault conditions, this paper
proposes the coordination control of a superconducting magnetic energy storage
(SMES), an active superconducting fault current limiter (SFCL), and distributed
generation units via wireless network communications. This coordination control
can smoothly separate the micro-grid from the main network in case of severe or
permanent faults, and assist the micro-grid to achieve the fault ride-through
(FRT) operation if the fault is minor or temporary. Details on the modeling,
control strategy, and network architecture are presented. Moreover, the
simulation analysis of a 10 kV class micro-grid including the SMES, SFCL, and
photovoltaic generation units is implemented in MATLAB. Concerning the
performance evaluation of the coordination control, not only severe and minor
faults, but also different communication delays are taken into account. The
results confirm the effectiveness of the proposed coordination control.
KEYWORDS:
1. Coordination
control
2. Distributed
generation
3. Micro-grid
4. Superconducting
fault current limiter (SFCL)
5. Superconducting
magnetic energy storage (SMES)
6. Wireless
communications
SOFTWARE:
MATLAB/SIMULINK
CONCLUSION:
In order to improve the stability of a micro-grid under short-circuit faults, this paper proposes and investigates the coordination of a SMES unit, an active SFCL, and multiple distributed generation units via the wireless communications. The severe and minor faults are considered, and the impacts of the wireless communication delay on the coordination performance are also studied. The results well demonstrate the effectiveness of the proposed coordination control, and it can maintain the power balance, accelerate the load recovery, suppress the PCC fault current, and mitigate the voltage-frequency fluctuation. Thus, the micro-grid’s transient performance is able to be enhanced considerably, and further the technical advantages of the SMES, active SFCL, distributed generation units and wireless communications can be fully utilized.
In
the near future, the improvement of the coordination control will be carried
out from multiple aspects, such as the parameter optimizations of the SMES and
the SFCL, the robustness advancement of the wireless network, the suitableness
enhancement of the coordination control for a large micro-grid/test system
including several DG resources and control structures. In addition, the current
coordination control does not consider the effects of the load dynamics on the
transient performance of the micro-grid, and it means that just two static
power loads are used. On the one hand, with regard to the necessity of
introducing the load dynamics, it may closely depend on whether the current
coordination control of the SMES, active SFCL and distributed generation units
is enough to stabilize the micro-grid under the fault conditions. On the other
hand, if more electrical devices take part in the coordination control, an
intelligent coordination method based on multi-agent system technology can be
properly applied. Related research results will be reported in later articles.
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