Measurment based voltage stability monitoring and control

Abstract

A measurement base voltage stability monitoring and control scheme having a means for measuring current and voltage phasors at a boundary bus of a load center; and an equivalent network having a fictitious bus with an aggregate load representative of all loads of the load center. The scheme further includes a computing device to calculate a voltage stability margin index based on the aggregate load of the fictitious bus and compare the voltage stability margin index to a pre-set threshold. The computing device causes an action to take place based on the comparison between the voltage stability margin index and the pre-set threshold.

What is claimed is: 
     
         1 . A voltage stability monitoring system, comprising:
 (a) a means for measuring current and voltage phasors at a boundary bus of a load center;   (b) an equivalent network having a fictitious bus with an aggregate load representative of all loads of the load center; and   (c) a computing device programmed to calculate a voltage stability margin index based on the aggregate load of the fictitious bus and compare the voltage stability margin index to a pre-set threshold, wherein the computing device is adapted to cause an action to take place based on the comparison between the voltage stability margin index and the pre-set threshold.   
     
     
         2 . The voltage stability monitoring system according to  claim 1 , wherein the equivalent network further includes a zero-voltage passive star network for connecting the fictitious bus to the boundary bus. 
     
     
         3 . The voltage stability monitoring system according to  claim 1 , wherein the load center includes a plurality of boundary buses. 
     
     
         4 . The voltage stability monitoring system according to  claim 1 , further including an external power system connected to the load center. 
     
     
         5 . The voltage stability monitoring system according to  claim 4 , wherein power is transferred from the external system to the load center through the boundary bus of the load center. 
     
     
         6 . The voltage stability monitoring system according to  claim 1 , wherein the action taken by the computing device is to provide information on a system at load center. 
     
     
         7 . The voltage stability monitoring system according to  claim 1 , wherein the action taken by the computing device is to control voltage stability at the load center.