A Hierarchical Coordinated Control Strategy for Power Quality Improvement in Energy Router Integrated Active Distribution Networks

Abstract

The energy router (ER) is a current power electronic device which can integrate distributed energy, provide power for different types of loads, and simultaneously realize the free flow of energy. In traditional active distribution networks, power quality is affected due to the access of photovoltaics (PV) and various loads. Hence, this problem can be improved by accessing the ER. This paper shows the power quality improvement of the grid when the ER is used to integrate PV, energy storage, and AC/DC loads. At the same time, an energy coordination strategy for ER is proposed. The IEEE 13 node model is developed to analyze power quality fluctuations when distributed energy and AC/DC loads are directly connected to the grid. For the power quality analysis, five indicators were selected and the hierarchical analysis method was used to obtain the indicators of power quality. After the use of ER under the coordinated control of ER, the energy is distributed twice and the power quality of the grid improves. The feasibility of ER topology and the control strategy have been verified through an established active distribution networks model with ER. It is verified that when the ER is connected to active distribution networks, the power quality improves accordingly, and it can effectively deal with the characteristics of distributed energy fluctuations and improve the flexibility of the power grid.