Electric Vehicle Charging Reliability Assessment Considering Failures of Power Systems and Power Electronics Components

The charging service of electric vehicles (EVs) is jointly influenced by the performance of internal power electronic components in charging stations and the power supply capacity of external power systems. To study charging reliability assessment under multiple impacts, this paper therefore proposes a reliability study spanning from component-level failure mechanisms to system-level analysis, establishing a multidimensional charging reliability assessment framework. First, for the core power electronic components within charging stations, aging failure distribution models are constructed using the Weibull distribution. Operational states are derived through Markov state transition theory. Subsequently, the failure distribution from the power electronic component level to the system level is investigated, with consideration of interactive effects with the power system. Finally, a joint assessment framework for charging availability (CA) and grid reliability is proposed based on the sequential Monte Carlo method. This framework quantifies charging service levels and grid reliability through specific indices. Case studies conducted on the IEEE 33 bus system demonstrate that component failures and power system faults collectively degrade EV charging service, while the diminished charging availability in turn compromises reliability of the power system.