Innovative Protection Strategies for Extensive Battery Storage integrated with AC Power Grid system

Furthermore, these systems facilitate access to diverse markets, encompassing financial stacking and the creation of contingency reserves. It is advantageous to minimize the necessity for costly infrastructure while optimizing the application of current transmission networks

However, it is essential to implement battery energy storage systems to address the challenges associated with managing the intermittency, as renewable energy sources such as solar and wind inherently depend on weather conditions, resulting in fluctuations in electricity generation. Moreover, increasing attention on BESS-connected utilities stems from the challenges that encountered at the AC-DC link. This system is characterized by two-way power flow, which can compromise system stability in the absence of adequate isolation actions.

additionally, battery energy storage integrated with an AC-grid system is often featured with a fault current limiter (FCL), which serves to regulate the magnitude of fault current originating from the BESS side. In the absence of appropriate equipment, short circuits within a BESS-AC grid may produce high current capable of damaging the converters and various other components. However, conventional protection systems utilized in AC grids may not be sufficient for bidirectional power flow system. The addition of fault current limiters (FCL) can further reduce the fault current level, thereby reducing the effectiveness of traditional protection methods. Furthermore, operating battery energy storage systems in either grid mode or off-grid mode introduces a range of complexities for protection system coordination. This is particularly evident in the context of overcurrent protection and AC common coupling busbar protection settings, which may be influenced during the off grid, whether by deliberate planning or by unexpected faults. The maximum fault level is expected to be considerably reduced, which will negatively affect busbar protection if a short circuit occurs at that moment. Moreover, there is an inadequate amount of research examining the protective methodologies in these contexts.

Consequently, a novel and flexible protection scheme for an AC-grid-interconnected BES system has been put forward, integrating intelligent execution and a resilient communication framework. The primary objective of this study is to examine critical issues and protection challenges associated with integrating battery energy storage systems (BESS) into alternating current power grid, while also offering insights for the development of effective protection systems. Simulation studies utilizing PSCAD/EMTDC reveal the efficacy of the proposed protection strategies. A variety of operational scenarios are analyzed to evaluate the proposed scheme for diverse fault types. The findings demonstrate a dependable approach for addressing the limitations of conventional protection strategies in the context of bidirectional power flow and reduced fault current.