BS EN 60099-8:2011 PDF

1   Scope This part of IEC 60099 covers metal-oxide surge arresters with external series gap ( externally gapped line arresters ( EGLA ) that are applied on overhead transmission and distribution lines, only to protect insulator assemblies from lightning-caused flashovers. This standard defines surge arresters to protect the insulator assembly from lightning-caused overvoltages only. Therefore, and since the metal-oxide resistors are not permanently connected to the line, the following items are not considered for this standard:

• switching impulse sparkover voltage;

• residual voltage at steep current and switching current impulse;

• thermal stability;

• long-duration current impulse withstand duty;

• power-frequency voltage versus time characteristics of an arrester;

• disconnector test;

• aging duties by power-frequency voltage.

Considering the particular design concept and the special application on overhead transmission and distribution lines, some unique re...