T/F: grid connected system more stable

TRUE (in general).

• In a large grid the total inertia ($\sum H$) of all connected machines is large, so a sudden load change or loss of a generator causes only a small change in frequency.
• The grid's low Thevenin impedance (high SCMVA) keeps bus voltages steady during disturbances; it acts like an "infinite bus" for each small plant.
• Spinning reserve is shared, so other plants pick up the load of a tripped unit.
• An isolated system has small inertia and little reserve, so frequency and voltage swing much more and it can collapse after losing one unit.

Limitation: very long weak ties may create inter-area oscillations and a fault can cascade, so a grid is more stable only when it is properly planned, protected and controlled.