Improved DC power flow method based on empirical knowledge of the system

This paper presents a new method to improve the accuracy of the DC power flow results while maintaining its computation efficiency and linear formulation. The proposed method uses empirical knowledge of the system, including observed voltage magnitudes and angles from historical data, to formulate correction terms. The correction terms are applied to bus power injections and line admittance matrix when DC power flow is calculated. Tests on the IEEE 30 bus and 118 bus systems, using either randomly varied bus loading or an IEEE standard load profile, showed that the average error in power flow calculation is reduced from about 5% to less than 1%, an average improvement of 80% in comparison with the traditional DC method. The improved DC method can be very useful when a large number of system power flow calculations under different generation/ loading conditions are needed. It can also be used in representing the system constraints in power market programs where empirical knowledge of the system is usually available and accuracy is of great importance.