Updating Load Bus Voltages

Let us start the procedure with bus-2 of the 5 bus 7 line system given in fig: 4.1. Since this is load bus, both the real and reactive power into this bus is known. We can therefore write from (4.12)

(4.13)

From the data given in Table 4.3 we can write

It is to be noted that since the real and reactive power is drawn from this bus, both these quantities appear in the above equation with a negative sign. With the values of the Y bus elements given in Table 4.2 we get V₂¹ = 0.9927 < − 2.5959° .

The first iteration voltage of bus-3 is given by

(4.14)

Note that in the above equation since the update for the bus-2 voltage is already available, we used the 1^st iteration value of this rather than the initial value. Substituting the numerical data we get V₃⁽¹⁾ = 0.9883 < − 2. 8258° . Finally the bus-4 voltage is given by

(4.15)

Solving we get V₄⁽¹⁾ = 0. 9968 < −3.4849° .