The program is designed to address short-circuits in meshed networks. Capacitors and non-rotating loads are not included in the calculations. For minimum short-circuit calculations the motor contribution is excluded. The resistance to reactance ( R/ X) ratios for different equipment can be calculated as per recommendations in the standard or entered by users as per the manufacturer data. For minimum short-circuit currents, the resistances are based on the estimated temperature at the end of the short-circuit condition. The resistances for cables, transmission lines and busways for maximum short-circuit current calculations are based on the conductor temperature at 20☌. Impedance correction factors are applied for network or utility ( K Q), generators ( K G), power stations units with on-load tap changer ( K S), power stations units without on-load tap changer ( K SO), and two- and three-winding transformers ( K T). The short-circuit impedances for electrical equipment are modified using impedance corrections factors that are calculated based on section 3. The values can be displayed in magnitude, magnitude and angle, or in real and imaginary quantities.įigure 2: Short-circuit currents decaying over time MethodologyĮasyPower uses the equivalent voltage source at the short-circuit location, symmetrical components impedance network, and the voltage factor c as described in section 2.3 of the standard. Corresponding voltages can be displayed at the buses. You can view the currents in various formats such as phase currents for A, B and C phases or in symmetrical components: positive sequence, negative sequence, zero sequence and the 3I0 value (3 times the zero sequence current).
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