Calculator #012LV short circuit100 V to 1 000 VIEC 60909-0

Short-Circuit Current Calculator — LV, up to 1 kV (IEC 60909-0)

Scope: a.c. three-phase systems with a nominal voltage from 100 V to 1 000 V (IEC 60909-0:2016, Clause 1). The voltage factor comes from Table 1, the transformer correction from Formula (12a), the peak current from 8.1.2 including the 1,15 factor and the 1,8 cap for low-voltage networks, and the thermal equivalent current from Clause 14. One table holds the whole network — feeders, transformers, cables, busways, reactors, motor groups, generators and converter-fed units connecting named busbars — and the nodal admittance matrix is built and inverted at the busbar you mark as the fault. The built-in validation reproduces the worked 400 V example of IEC TR 60909-4:2000, clause 3, at all three fault locations.

Above 1 kV? Use the companion tool #002 Short-Circuit — MV 1 to 33 kV, which carries the medium-voltage element library, several parallel sources per busbar and the earthing-arrangement selector.

System and voltage factor

Nominal system voltage Un, V

Voltage tolerance (Table 1)

Frequency, Hz

Short-circuit duration Tk, s

Conductor temperature at the end of the short circuit, °C Minimum currents only - Formula (32), α = 0,004/K.

Upstream network

How the network above the fault is represented

Project overview - every circuit, every busbar

Network

#	Element	Name	From the libraryPRO	From busbar	To busbar	p1	p2	p3	p4	p5	p6	p7

Circuit name

Fault at busbar

Element to add

Result at the fault

Protective device at the fault point

Device and standard

Rated current I_n, A

Rated ultimate breaking capacity I_cu, kA Manufacturer data - it is not a tabulated value.

Rated short-time withstand I_cw, kA Leave 0 for a device without an I_cw rating (most MCBs and MCCBs).

I_cw duration, s

Operating current I_a, A From the device's tripping curve - the current that operates it within the time IEC 60364-4-41 Table 41.1 requires. 0 skips the check.

Fault level at every busbar, and the report

The same network, solved at each of its busbars in turn: the maximum regime, the minimum regime a protective device has to see, and the peak current at that point.

Glossary

Built-in validation tests

#	Case	Published	Computed	Status

Every case is a value printed in IEC TR 60909-4:2000, clause 3 (the 400 V system of Figure 6) or in IEC 60909-0:2016 Table 1. The panel runs in your browser, so nothing here is taken on trust. How every other engine on the site is checked: calculation validation; how they are built: methodology.