IEEE 33-Node Distribution Network Power Flow Calculation Program using Forward/Backward Sweep Method

In power system analysis, distribution network power flow calculation represents a fundamental and critical research area. The IEEE 33-node model serves as a classic test case frequently employed to validate algorithm effectiveness. The Forward/Backward Sweep method has emerged as one of the mainstream approaches for distribution network power flow analysis due to its computational simplicity and excellent convergence properties. The algorithm's core concept operates in two distinct phases implemented through iterative loops: The forward sweep phase calculates power flow from terminal nodes toward the root node, updating branch currents using cumulative load summation techniques. The backward sweep phase propagates voltage values from the root node to terminal nodes, correcting node voltages through Ohm's law applications with impedance parameters. Code implementation typically involves initializing node voltages to nominal values (e.g., 1.0 p.u.), followed by iterative calculations until voltage mismatches meet convergence criteria (commonly 1e-6 tolerance). Compared to traditional methods like Newton-Raphson, the Forward/Backward Sweep method proves particularly suitable for radial distribution network structures. It effectively handles high R/X ratio line characteristics and eliminates Jacobian matrix formation, significantly reducing computational complexity. Practical implementation requires careful handling of engineering constraints including distributed generation integration, voltage limit violations, and load variation scenarios. The algorithm structure typically incorporates while-loop iterations with convergence checks, branch current calculations using power-voltage relationships, and voltage updates through backward propagation.