Forward-Backward Sweep Method for Distribution Network Power Flow Calculation

The Forward-Backward Sweep Method is an iterative algorithm commonly used for power flow calculation in distribution networks, particularly suitable for radial network configurations. This approach solves voltage, power, and current distributions across network nodes through alternating forward and backward sweep operations. In code implementation, this typically involves setting up node-branch data structures and defining convergence thresholds.

The forward sweep step propagates power and current from network terminals toward the source node. Given known terminal node voltages, the algorithm calculates branch current flows and power losses while progressing upstream. Code implementation requires computing branch currents using nodal power injections and applying impedance-based loss calculations through sequential processing of downstream branches.

The backward sweep step propagates voltage from the source node toward network terminals. Utilizing current and power distributions obtained from the forward sweep, the algorithm updates nodal voltages by accounting for voltage drops along branches. Programming this step involves voltage correction calculations using branch impedances and implementing topological traversal from root to leaf nodes.

The method's advantage lies in its computational simplicity and reliable convergence for radial networks. The algorithm iterates until voltage and power changes meet convergence criteria, ultimately determining the network's steady-state operating condition. Implementation typically includes while-loop structures with convergence checks using maximum voltage difference or power mismatch tolerances.

Practical applications require handling nodal power balance equations and branch voltage drop equations while considering distribution network impedance characteristics and topological structure. The method accommodates purely resistive networks and extends to complex impedance systems through phasor calculations, with code implementations often featuring rectangular or polar coordinate systems for complex number operations.