Grenstrømmene

Grenstrømmene is a Norwegian term used in electrical engineering to describe the currents that flow through the individual branches of an electrical network. They are the currents that split from a common node into parallel paths and may later recombine, as opposed to the main current that flows through a single path before division. The concept is central to circuit analysis and helps explain how voltage and resistance determine how current is distributed in a circuit.

In circuit theory, Kirchhoff's Current Law states that the algebraic sum of currents at a node is zero, so the main current entering a node equals the sum of the branch currents. In a purely resistive parallel network powered by a voltage source V, the voltage across each branch is V, and branch currents are I_i = V / R_i. The total current is I_total = sum of I_i, and the equivalent resistance satisfies 1/R_eq = sum(1/R_i).

In alternating current or complex impedance analysis, branch currents are phasors I_i = V / Z_i, where Z_i is the branch impedance. The magnitudes and phases of the grenstrømmene depend on the impedances, and the sum of the branch currents equals the supply current, in accordance with KCL.

Measurement and design considerations include placing ammeters in series with each branch to monitor I_i, ensuring currents stay within component ratings, and recognizing that unbalanced branch currents can indicate faults or asymmetries in the network. Grenstrømmene thus provide a practical framework for understanding current distribution in parallel circuits.