The transient stability of a 100% renewable energy power system considering current limits is studied in this paper. First

a transient stability analysis model for a fully Virtual Synchronous Generator (VSG) networked system is constructed. Next

the impact of current limiting on the range of the transient energy function is investigated based on the perturbation analysis theory of optimization problems. For a standard form optimization problem

if all the Lagrange multipliers of the equality constraints are negative

an upper bound exists for the objective function. This demonstrates that the transient energy function must have a maximum value when no VSG triggers current limiting. Subsequently

by constructing 𝑛 optimization subproblems

the maximum potential energy when all VSGs do not enter the current limiting control mode is solved

deriving a conservative stability criterion for the full VSG networked system. Finally

the correctness of the proposed transient stability criterion for a 100% renewable energy power system is validated using a modified 3-machine 9-bus system.