Driven by ever increasing energy demands, environmental constraints, deregu
lation and privatisation of the power supply industry, existing transmissio
n systems are often operated min stressed to the limit and occasionally bey
ond the performance capability of their original design in order to maximis
e asset utilisation. To ensure that under these conditions the economical,
reliable and secure operation of the grin is maintained, the need for vario
us aspects of power flow management within the power systems is becoming in
creasingly evident.