The active power balance problem caused by the network loss in DC power flow algorithm is researched. Two methods are proposed to achieve active power balance

including adjusting the generator output or power load

and adopting equivalent load model. In order to apply this equivalent load model without dependence on convergent initial power flow

a new effective iterative method is also presented to calculate the equivalent loads. The improved DC power flow algorithm proposed retains the linearity and rapidity of the standard DC power flow algorithm

while achieving much higher calculation accuracy. Plenty of actual calculation examples show that the improved DC power flow algorithm is effective and practical

as the power flow result calculated by the improved algorithm is much closer to the actual value than by the standard algorithm.