The network power balance equation

[lefang16]

I read in the FAQ that ANDES do not use a Y bus matrix to define the network terminal constraint for the machine, and I do not find power balance equation as the algebraic equations in the SynGen model or the ACtypology model, I wonder to which model are these power balance equations declared and stored? I'm looking for something to replace the following terminal constraint in the classic formulation,

Thanks for your answer!