Identification of Weak Bus and Voltage Stability Enhancement

Abstract: This paper describes sensitivity indicator method to identify weakest bus of the system. It also describes method of calculating the amount of reactive power to be injected at the load bus to avert the voltage instability as the load on the load bus increases. In this paper IEEE-57 BUS system has been considered. First, the weakest bus is identified using sensitivity indicator method. Then Load flow analysis is performed using the Newton-Raphson (N-R) method. When load flow doesn’t converge after the demand has increased on a bus then it indicates that it requires reactive power compensation on that bus. The Additional capacitor that needs to be switched on is computed by an iterative procedure. Thereafter, in the actual usage, based upon the computed Table, given any load one may determine the level of compensation required to avert voltage collapse. By using Jacobian element additional compensation required to improve the bus voltage can be determined.

Keywords: weak bus, voltage instability, sensitivity indicator, load flow