Harmonic impedance of armored cables for low-voltage power distribution in buildings

This paper presents an experimental investigation into the harmonic impedance of 4/c armoured cables for low-voltage power distribution in buildings. The impedance of the cables up to the 49(th) order was measured by injecting a steady-state current into the tested cables. Phase impedance matrices for the cables with CSAs of 95mm(2) to 400mm(2) were obtained. Each of the matrices contained only two independent elements. These elements were obtained by looking at the impedance tables, or simply using the derived empirical formulas presented in this paper. It was found that the cable resistance rose with increasing harmonic frequency because skin and proximity effects. The cable inductance, however, declined significantly, and could reached 50% of its 50Hz value at order 49.