Voltage collapses usually occur on power system which are heavily loaded or faulted or have shortage
of reactive power. Voltage collapse is a system instability involving many power system components.
In fact, a voltage collapse may involve an entire power system.
Voltage collapse is typically associated with reactive power demand of load not being met due to
shortage in reactive power production and transmission.
Voltage collapse is a manifestation of voltage instability in the system. The definition of voltage
stability as proposed by IEEE/CIGRE task force is as follows: