Abstract
In this paper, a hierarchical optimal operation strategy for a hybrid energy storage system (HESS) is proposed, which is suitable to be utilized in distribution networks (DNs) with high photovoltaic (PV) penetration to achieve PV power smoothing, voltage regulation and price arbitrage. Firstly, a fuzzy-logic based variable step-size control strategy for an ultracapacitor (UC) with the improvement of the lifetime of UC and tracking performance is adopted to smooth PV power fluctuations. The impact of PV forecasting errors is eliminated by adjusting the UC power in real time. Secondly, a coordinated control strategy, which includes centralized and local controls, is proposed for lithium-ion batteries. The centralized control is structured to determine the optimal battery unit for voltage regulation or price arbitrage according to lithium-ion battery performance indices. A modified lithium-ion battery aging model with better accuracy is proposed and the coupling relationship between the lifetime and the effective capacity is also considered. Additionally, the local control of the selected lithium-ion battery unit determines the charging/discharging power. A case study is used to validate the operation strategy and the results show that the lifetime equilibrium among different lithium-ion battery units can be achieved using the proposed strategy.
Highlights
Due to the global energy crisis and environmental concerns, the installed capacity of photovoltaics (PVs) in distribution networks (DNs) is increasing rapidly
In the coordinated control for lithium-ion battery, centralized control selects the optimal battery unit to perform voltage regulation or price arbitrage according to evaluation matrix considering battery performance indices such as State of Charge (SOC), charging/discharging power, remaining lifetime, voltage sensitivity factor (VSF), and voltage cost sensitivity factor (VCSF)
In real-time operation, when the actual value of PV power is larger than the forecast value, the voltage may exceed the upper limit if the UC power remains at the value given by a PV power smoothing strategy based on PV forecasting data
Summary
Due to the global energy crisis and environmental concerns, the installed capacity of photovoltaics (PVs) in distribution networks (DNs) is increasing rapidly. In [25], the authors propose a semi-empirical lithium-ion battery degradation model by combining some fundamental theories of the battery degradation with battery aging test results These studies provide a good reference and facilitate the performance improvements of the operation strategy. A rule-based hierarchical operation strategy of HESS, including lithium-ion batteries and UCs, for PV power smoothing, voltage regulation, and price arbitrage is proposed. In the coordinated control for lithium-ion battery, centralized control selects the optimal battery unit to perform voltage regulation or price arbitrage according to evaluation matrix considering battery performance indices such as State of Charge (SOC), charging/discharging power, remaining lifetime, voltage sensitivity factor (VSF), and voltage cost sensitivity factor (VCSF). A multi-objectives hierarchical operation strategy with consideration of PV power smoothing, voltage regulation, and price arbitrage is proposed, which can improve the effectiveness of utilizing HESS.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
