Let real and reactive power generated at bus- i be denoted by PGi and QGi respectively. Also let us denote the real and reactive power consumed at the i th th bus by PLi and QLirespectively. Then the net real power injected in bus- i is (4.8)
Let the injected power calculated by the load flow program be Pi, calc . Then the mismatch between the actual injected and calculated values is given by\
In a similar way the mismatch between the reactive power injected and calculated values is given by
It is to be noted that (4.6) and (4.7) are used for the calculation of real and reactive power in (4.9) and (4.10). It is expected that mismatches ΔPi and ΔQi reduce with each iteration and the load flow is said to have converged when the mismatches of all the buses become less than a very small number.