CENELEC - EN 50522
Earthing of power installations exceeding 1 kV a.c.
|Publication Date:||1 March 2022|
|ICS Code (Fuses and other overcurrent protection devices):||29.120.50|
This document is applicable to specify the requirements for the design and erection of earthing systems of electrical installations, in systems with nominal voltage above 1 kV AC and nominal frequency up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.
NOTE 1 The technical and procedural principles of this document can be applied when third parties' installations and facilities are planned and/or erected in the vicinity of HV electrical power installations.
For the purpose of interpreting this document, an electrical power installation is considered to be one of the following:
a) substation, including substation for railway power supply;
b) electrical power installations on mast, pole and tower; switchgear and/or transformers located outside a closed electrical operating area;
c) one (or more) power station(s) located on a single site; the electrical power installation includes generators and transformers with all associated switchgear and all electrical auxiliary systems. Connections between generating stations located on different sites are excluded;
d) the electrical system of a factory, industrial plant or other industrial, agricultural, commercial or public premises;
e) electrical power installations on offshore facilities for the purpose of generation, transmission, distribution and/or storage of electricity;
f) transition towers/poles between overhead lines and underground lines.
The electrical power installation includes, among others, the following equipment:
- rotating electrical machines;
- transformers and reactors;
- wiring systems;
- earthing systems;
- buildings and fences which are part of a closed electrical operating area;
- associated protection, control and auxiliary systems;
- large air core reactor.
NOTE 2 In general, a standard for an item of equipment takes precedence over this document.
This document does not apply to the design and erection of earthing systems of any of the following:
- overhead and underground lines between separate installations;
- electrified railway tracks and rolling stock;
- mining equipment and installations;
- fluorescent lamp installations;
- installations on ships according to IEC 60092 (all parts) and offshore units according to IEC 61892 (all parts), which are used in the offshore petroleum industry for drilling, processing and storage purposes;
- electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
- test sites;
- medical equipment, e.g. medical X-ray equipment.
NOTE 3 The standard EN 50341 series, Overhead lines exceeding AC 1 kV, specifies requirements for the design and erection of earthing systems in overhead lines.
NOTE 4 The scope of this document does not include the requirements for carrying out live working on electrical power installations.
NOTE 5 The scope of this document considers safety requirements for HV installations and its influences on LV installations. For electrical installation up to 1 kV, the standard HD 60364 series applies.