The first (and probably the major) problem is fault currents.

Series reactors can also be used to limit fault currents.

Impedance should not be too low for desired maximum fault current.

Now and then he was sure he could detect a fault current against his cheek.

Fault currents, on the other hand, can well be several hundreds, or even several thousands of times normal.

In practice, the combined resistance was not sufficiently low enough and the fault current would generally seek other routes.

Knowing the resistance read off the prospective Fault Current from the graph.

This results in much lower (than traditionally expected) earth fault current affecting the earth grid.

Its primary purpose is to carry fault currents.

Fault current is electronically limited to approximately 1.5 amps.

Also non-replaceable internal fuses will be required to limit the fault current leaving the enclosure.

This paper can be treated as a guide or a reference document for calculating the fault currents in a distribution network.

This proves that the external earth and the mains supply coming in is adequate to take any fault current, should it occur.

A large solidly-grounded distribution system may have thousands of amperes of ground fault current.

If the fault is a long way away the fault current will usually be equally shared amongst parallel live wires.

Significant fault current can be diverted via conduction and induction into the overhead earth wires.

(The difference is that higher fault current is then needed to reach this voltage.)

As a result, ground fault currents have no path to be closed and thus have negligible magnitudes.

A fault current is typically caused by an accident or unintended event, such as lightning or contact between power lines and trees.

Figure: Industrial Switchboard An example of an installation where a high fault current would be available.

Conductors on overhead lines are subject to two different sources of severe temperature excursions: lightning strike and fault current.

If these are removed while the capacitor is charged, and they contact a solder joint, fault currents cam flow.

The magnetically or electrically shielded versions are normally supplied for fault current limiting on power systems.

Fault current can be limited by using current limiting devices such as grounding resistors or fuses.

Impedance can be added after the secondaries are summed to limit maximum fault currents (the 3I path).