Q10Power System - I
Question
Q.10. What is the difference between synchronous and asynchronous grid?
Answer
A synchronous grid keeps all interconnected generators locked at the same frequency and phase through direct AC ties, while an asynchronous grid links two or more independently operating AC systems only through a non-synchronizing interface (typically HVDC), allowing each side to maintain its own frequency/phase reference.
In a synchronous grid, every generator across the entire interconnected network operates at exactly the same electrical frequency and maintains a fixed relative phase relationship with every other generator, connected via direct AC transmission ties that allow completely free active and reactive power exchange and mutual inertial support during disturbances. In an asynchronous grid, two (or more) separate AC systems are connected only through a non-synchronizing link such as an HVDC tie, which fully decouples the frequency and phase of the two sides, allowing controlled power exchange between grids that may run at different nominal frequencies or that are deliberately kept electrically decoupled from each other for improved stability and fault-containment, at the cost of losing the automatic mutual inertial frequency support that a fully synchronous interconnection would provide.