Reactive power dispatch incorporating voltage stability

The cause of the 1977 New York blackout has been proved to be the reactive-power problem. The 1987 Tokyo blackout was believed to be due to a reactive-power shortage and a voltage collapse at the summer peak load. These events have confirmed the importance of reactive-power planning and dispatching in maintaining the security of modern power systems. Appropriate control of system voltage profiles can enhance system security and may also reduce system losses. Previous investigations by the same authors have shown that a voltage collapse proximity indicator based on the optimal impedance solution of a two-bus system can be extended to an actual network. The authors describe a linear reactive power dispatch algorithm which incorporates this indicator to minimise the possibility of voltage collapse in the system