The Load Flow Analysis helps understand the operation and behaviour of the system when a generator trips or when a big load is suddenly cut off. Load Flow Analysis also helps identify routes to transfer power when a transmission line has to be isolated due to a fault. This ensures reliable power supply and ensures quick restoration in the event of blackouts.
Load Flow Analysis is done during the design of the power system. It should also be done before any modification of the power system such as the addition of loads or generating units.