EddyWirbelstrom
Electrical
- Feb 17, 2002
- 214
thread238-292509
IEEE1584 does not specify a short-circuit current calculation method.
Pre version 8 of SKM PTW arc flash analysis software to IEEE 1584 used the PTW ‘comprehensive’ short-circuit current calculation method which is the classical impedance reduction method without the multiplying factors used by IEC 60909-0.
Version 8 of SKM PTW arc flash analysis software to IEEE 1584 introduced the IEC 60909 option.
IEC 60909-0 Table 1 recommends using a ‘Voltage factors c’ when calculating max and min short-circuit current. I”k = c Un / ( √3 * Z ). The ‘c factor’ for low voltage is 0.95.
For voltages below 1000V, Amendment 1 Section 5.2 of IEEE 1584 recommends calculating two arcing currents, one using 100% of rated volts and one at 85% of rated volts. The higher resulting incident energy to be used.
If the IEC 60909 option is used in the PTW arc flash program, the ‘c factor’ of 0.95 will be used instead of the 0.85 factor when calculating the second arcing current.
This is not in accordance with Amendment 1 Section 5.2 of IEEE 1584.
IEEE1584 does not specify a short-circuit current calculation method.
Pre version 8 of SKM PTW arc flash analysis software to IEEE 1584 used the PTW ‘comprehensive’ short-circuit current calculation method which is the classical impedance reduction method without the multiplying factors used by IEC 60909-0.
Version 8 of SKM PTW arc flash analysis software to IEEE 1584 introduced the IEC 60909 option.
IEC 60909-0 Table 1 recommends using a ‘Voltage factors c’ when calculating max and min short-circuit current. I”k = c Un / ( √3 * Z ). The ‘c factor’ for low voltage is 0.95.
For voltages below 1000V, Amendment 1 Section 5.2 of IEEE 1584 recommends calculating two arcing currents, one using 100% of rated volts and one at 85% of rated volts. The higher resulting incident energy to be used.
If the IEC 60909 option is used in the PTW arc flash program, the ‘c factor’ of 0.95 will be used instead of the 0.85 factor when calculating the second arcing current.
This is not in accordance with Amendment 1 Section 5.2 of IEEE 1584.