Optimal Allocation and Operation of Battery Energy Storage Systems in Highly DER-Penetrated Active Distribution Networks

Abstract

Modern power systems are facing growing penetration of renewable distributed generation (DG) in active distribution networks (ADNs), mainly driven by energy transition, decarbonization and economic benefits. However, renewable DG such as wind turbine and solar photovoltaic (PV) characterize fluctuating and intermittent output power as well as non-dispatchable attributes. Also, the renewable generation cannot fully align with load consumption, resulting in a supply-demand energy mismatch. To address uncertainties of renewable DG and improve renewable energy utilization efficiency, battery energy storage systems (BESSs) are considered as a promising technology for renewable integration in power systems. Thus, this thesis focuses on the optimal allocation and operation of BESS in highly distributed energy resource (DER)-penetrated ADNs. Firstly, a robustly optimal allocation method for BESSs is developed to alleviate power unbalance and voltage rise, thus improving the PV hosting capacity of ADNs. Considering random locations and capacities of the distributed rooftop PVs, future PV installations are regarded as uncertainties, which provides a new perspective on hosting capacity improvement. Secondly, for energy management, a two-stage coordinated method of day-ahead demand response and BESS is developed to minimize the total operating cost. Considering the limited BESS capacity and time-coupling of state of charge (SoC) during the scheduling, an SoC interval management method is proposed to improve BESS dispatch efficiency from the whole-day perspective. Thirdly, this SoC interval management is integrated into an adaptive BESS dispatch method for unbalanced microgrid operation. The corresponding optimization problem is solved by a hybrid interval-robust optimization method. Fourthly, different ownerships of DERs also bring challenges to microgrid energy management. A transactive energy sharing approach between a microgrid operator and multiple DER-aggregators is developed with a distributed coordination framework. A two-settlement internal transactive energy market is proposed to support this energy sharing. The uncertainties in the above methods are properly modelled and addressed by different optimization methodologies. The proposed methods have been successfully demonstrated and compared with existing works. The results verify their high efficiency and robustness against uncertainties.