Arcing fittings
Arcing fittings are designed to compensate electrical potential along the insulator string, to create a flashover distance at the insulator string, to support an air discharge in case of bias voltage, to protect the insulators and conductors that are placed close to insulator strings against arcing after jumping over the insulating distance. The fittings should withstand thermal and dynamic influence of spcified short-circuit current. They can be burnt or decreased by arc burning, but damage of the insulators as well as jointing fittings should be avoided. Nominal short-time current Itn per one second is based on the short-time current density 80 A/mm² when the initial temperature is 30 °C and maximum temperature app. 400 °C. Nominal grid voltage UN specifies the voltage up to which the fitting can be used. It is recomended to agree the requirements on effectivness of the arcing fittigs or duration of shortcircuit arc in advance.
