Apart from the generator voltage, frequency and power rating, it is usually necessary to know the external earth fault loop impedance (Ze) and the prospective fault current (If). It is also necessary to know some of the other characteristics of the generator source, such as how the system is configured and whether such a configuration can offer adequate protection, particularly against indirect contact.
Apart from voltage rating and load capabilities, one of the most important characteristics of the generator set is its performance under fault conditions, particularly where automatic disconnection for fault protection is effected by an overcurrent protective device. Fault protection by means of the protective measure Automatic Disconnection of Supply (ADS) relies, in part, on a sufficiently high fault current to flow to cause automatic disconnection.
Such information is generally available only from the generator manufacturer who, upon request, should be able to provide a graphical representation of generator sub-transient, transient and steady-state performance under fault conditions. From this information, an assessment of the effectiveness of the protective measures can be made.
Regards
Dichroic
