Section VII:   Load Flow Results

In this section we shall discuss the results of the load flow. It is to be noted here that both Gauss-Seidel and Newton-Raphson methods yielded the same result. However the Newton-Raphson method converged faster than the Gauss-Seidel method. The bus voltage magnitudes, angles of each bus along with power generated and consumed at each bus are given in Table 4.4. It can be seen from this table that the total power generated is 174.6 MW whereas the total load is 171 MW. This indicates that there is a line loss of about 3.6 MW for all the lines put together. It is to be noted that the real and reactive power of the slack bus and the reactive power of the P-V bus are computed from (4.6) and (4.7) after the convergence of the load flow.

Table 4.4 Bus voltages, power generated and load after load flow convergence.

The current flowing between the buses i and k can be written as

(4.52)

Therefore the complex power leaving bus- i is given by

(4.53)

Similarly the complex power entering bus- k is

(4.54)

Therefore the I ² R loss in the line segment i-k is

(4.55)

The real power flow over different lines is listed in Table 4.5. This table also gives the I² R loss along various segments. It can be seen that all the losses add up to 3.6 MW, which is the net difference between power generation and load. Finally we can compute the line I²X drops in a similar fashion. This drop is given by

(4.56)

However we have to consider the effect of line charging separately.

Table 4.5 Real power flow over different lines.