Battery Storage Configuration of AC/DC Hybrid Distribution Networks

The upscaling requirements of energy transition highlight the urgent need for ramping up renewables and boosting system efficiencies. However, the stochastic nature of excessive renewable energy resources has challenged stable and efficient operation of the power system. Battery energy storage systems (BESSs) have been identified as critical to mitigate random fluctuations, unnecessary green energy curtailment and load shedding with rapid response and flexible connection. On the other hand, an AC/DC hybrid distribution system can offer merged benefits in both AC and DC subsystems without additional losses during AC/DC power conversion. Therefore, configuring BESSs on an AC/DC distribution system is well-positioned to meet challenges brought by carbon reductions in an efficient way. A bi-level optimization model of BESS capacity allocation for AC/DC hybrid distribution systems, considering the flexibility of voltage source converters (VSCs) and power conversion systems (PCSs), has been established in this paper to address the techno-economic issues that hindered wide implementation. The large-scale nonlinear programming problem has been solved utilizing a genetic algorithm combined with second-order cone programming. Rationality and effectiveness of the model have been verified by setting different scenarios through case studies. Simulation results have demonstrated the coordinated operation of BESS and AC/DC hybrid systems can effectively suppress voltage fluctuations and improve the cost-benefit of BESSs from a life cycle angle.

Automated summary

The urgency of energy transition requires the rapid development of renewable energy and improvement of system efficiencies. However, the unpredictable nature of excessive renewable energy poses challenges to stable and efficient power system operation. Battery energy storage systems (BESSs) are crucial in mitigating random fluctuations and optimizing green energy usage. Additionally, an AC/DC hybrid distribution system can combine the benefits of both AC and DC subsystems without incurring additional losses during power conversion. This paper presents a bi-level optimization model for allocating BESS capacity in AC/DC hybrid distribution systems, considering the flexibility of voltage source converters and power conversion systems. Case studies and simulation results demonstrate the effectiveness of this model in suppressing voltage fluctuations and improving the cost-benefit analysis of BESSs from a life cycle perspective.