Protection of transportation and distribution lines and cables

This section deals with the protection of extra-high voltage (EHV) and high-voltage (HV) networks against short-circuits and insulation faults; protection against abnormal operation of the generation-transmission-distribution system (loss of synchronism, drop in frequency, voltage drops) is covered in the section "Electrical power transmission and interconnection networks. Operation and regulation" [D 4 090] and will not be repeated here.

In the previous dossier [D 4 801] "Protection of transmission and distribution networks against short-circuits and insulation faults", the following points were addressed:

• performance and constraints imposed on protection systems by different types of network;

• presentation of the internationally accepted protection classification ;

• reminder of the influence of transient conditions on protection behavior ;

• basic relay measurement functions.

The present [D 4 802] file describes the principles of protection and relays more particularly adapted to overhead lines and underground cables.

In line with current language, we retain the notations THT (225 and 400 kV) and HT (63 and 90 kV), although the current designation (UTE C 18-510) is HTB for all voltages above 50 kV.

This dossier is part of a series on the protection of transmission and distribution networks:

• " Presentation " [D 4 800v2]  ;

• "Short-circuit and insulation fault protection"