No abstract

No abstract

Battery energy storage system (BESS) is a pivotal component to increase the penetration of renewable generation and to strengthen the stability and reliability of the power system. In this paper, for the purpose of the state of charge (SOC) balancing and reactive power sharing, a multiagent system (MAS)-based distributed control model, which contains a top layer communication network built by agents and a bottom-layer microgrid composed of BESSs, distributed generators (DGs), and Loads, is provided. Next, a systematic method is designed to build the control laws for agents from any given network, where each agent on the top communication network collects the states of BESSs, DGs it connects and exchanges information with its neighboring agents. Moreover, two theorems, which provide guidelines to design distributed control laws for SOC balancing and reactive power sharing between BESSs, are proposed to show the convergent property of the proposed control laws. Furthermore, several simulation cases are employed to validate the effectiveness of the proposed control model when environmental conditions and time-varying load demands are considered. Finally, the simulation results verify the effectiveness of the proposed control model, i.e., the SOC balancing and proportional reactive power sharing are achieved as expected. Furthermore, our approach has the fast convergent speed of SOC balancing of BESSs, compared to the existed method. INDEX TERMS Battery energy storage system (BESS), distributed control, state of charge (SOC) balancing, reactive power sharing, microgrids.

Battery energy storage systems (BESS) have wide applicability for frequency regulation services in power systems, owing to their fast response and flexibility. In this paper, a distributed method for frequency regulation based on the BESS is proposed, where the method includes two layers. The upper layer is a communication network composed of agents, which is used to transmit and process information, whilst the bottom layer comprises the power system with the BESS, which provides a frequency regulation service for the system. Furthermore, a set of fully distributed control laws for the BESS are derived from the proposed distributed method, where economic power dispatch and frequency recovery are simultaneously achieved. Finally, simulations were conducted to evaluate the effectiveness of the proposed method. The results show that the system frequency regulation and economic power dispatch are achieved after considering the limits of the battery state of charge and communication delays.

In remote areas, large power stations are often installed to supply local loads due to the difficulties of power transmission. However, with the development of renewable energies and poverty alleviation programs, many renewable energy stations have been installed in such areas. This large amount of surplus and fluctuating energy causes a poor voltage quality, and this problem is difficult to solve with traditional methods. Adding transmission lines can be a feasible solution, but the related research is limited. To provide a guideline for this solution, a network optimization algorithm is proposed in this paper. In the process, a sub-grid that is far from the national grid with an imbalanced power supply and demand is connected to the national grid directly to improve the power quality. First, the linear performance index power mileage is defined to facilitate the calculation and help denote the voltage quality. Then, an iterative algorithm is formed to perform the network optimization and automatically choose the number of clusters. A case study of an actual power grid in Chongqing, China, and an IEEE 123-bus case are used to verify our algorithm. The results show there is a great improvement in the voltage profile.