IEC TR 60909-2:2008

IEC 60909-2:2008(E) comprises data of electrical equipment collected from different countries to be used when necessary for the calculation of short-circuit currents in accordance with IEC 60909-0. It may be applied for calculating short-circuit currents in low-voltage networks if they are in accordance with typical equipment employed in the user's country. The collected data and their evaluation may be used for medium- or high-voltage planning purposes and also for comparison with data given by manufacturers or electricity suppliers. For overhead lines and cables the electrical data may in some cases also be calculated from the physical dimensions and the material following the equations given in this report. This second edition cancels and replaces the first edition published in 1992 and constitutes a technical revision. The significant technical changes with respect to the previous edition are as follows: - Subclause 2.5 gives equations and examples for the calculation of the positive-, the negative- and the zero-sequence impedances and reduction factors for high-, medium and low-voltage cables with sheaths and shields earthed at both ends. - Subclause 2.7 gives equations and figures for the calculation of the positive-sequence impedances of busbar configurations.