构网型储能所接线路电流差动保护适应性分析及改进判据研究OA

The short-circuit current provided by the grid-forming energy storage power sources(GFESPSs)distinct from conventional power sources due to its unique operation and control principle.Consequently,the conventional current differential protection deployed in the connected power grid is exposed to potential maloperation risks.Thus,this paper focuses on the widely adopted grid-forming energy storage based on virtual impedance.The short-circuit current fed by the GFESPSs is firstly analyzed.Further,the influence of the virtual impedance ratio and the GFESPSs'capacity on the currents phase angle difference and amplitude ratio on both sides of the connected line is developed.And the fault scenarios resulted in the incorrected operation of traditional current differential protection are revealed due to the integration with the GFESPSs.Aimed at the problems,an improved differential protection criterion is proposed based on the adaptive correction of the current phasor ratio.The effectiveness of the proposed protection criterion is verified through PSCAD/EMTDC simulation experiments.It is verified that the proposed criterion can identify correctly and reliably both internal and external faults of the line connected with GFESPSs.