High penetration of inverter-based renewable era (sun PV, wind) introduces new dynamics and balance challenges to trendy power systems. unlike traditional synchronous mills, inverter-interfaced sources make contributions little to machine inertia and trade fault response, voltage help, and frequency dynamics. This paper offers a comprehensive look at of balance troubles springing up from huge-scale renewable integration and proposes modelling, analytical, and manage strategies to make sure relaxed operation. We review literature, define stability classes (frequency, small-sign, transient, voltage/reactive, and rotor-perspective equivalents for low-inertia grids), endorse a hierarchical analysis and control structure, describe simulation-based totally assessment strategies (time-area EMT and phasor research), and advocate mitigation measures along with grid-forming inverters, artificial inertia, rapid frequency response, adaptive protection, and coordinated reactive power manage. consultant simulation situations display how suitable inverter manage and coordination can repair balance margins and restriction frequency nadir, voltage tours, and fee-of-exchange-of-frequency (RoCoF) beneath excessive renewable shares. We finish with deployment concerns, open studies guidelines and counseled benchmarks.