Section II: Modification of Bus Impedance Matrix
Modification of Bus Impedance Matrix
Equation (3.1) gives the relation between the bus impedance and admittance matrices. However it may be possible that the topology of the power system changes by the inclusion of a new bus or line. In that case it is not necessary to recompute the Y_{bus} matrix again for the formation of Z_{bus} matrix. We shall discuss four possible cases by which an existing bus impedance matrix can be modified.
Let us assume that an n bus power system exists in which the voltagecurrent relations are given in terms of the bus impedance matrix as

(3.30) 
The aim is to modify the matrix Z_{orig} when a new bus or line is connected to the power system.
