Substation earthing is critical both to the operational performance of the power system, and the provision of a safe working environment. It is a salient area of design when either constructing a new substation or extending or modifying an existing substation. Substation earthing is a highly specialist subject in its own right, and therefore this chapter will provide an overview of the basic theory and key requirements, relevant to power network construction, as summarised below: Objectives and regulations, Resistivity, Earth electrode systems, Earthing conductors and earth mats, Earthing system and earth fault current, Voltage limits, Practical considerations, Earthing design considerations.
Chapter Contents:
- 12.1 Introduction
- 12.2 Objectives and regulations
- 12.2.1 Historical
- 12.2.2 Regulatory requirements
- 12.2.3 Substation earthing objectives
- 12.3 Earth resistivity
- 12.3.1 Resistivity
- 12.4 Earth electrode systems
- 12.4.1 Types of electrodes
- 12.4.2 Driven vertical rods
- 12.4.3 Buried horizontal or vertical plate
- 12.4.4 Buried horizontal wire (or strip)
- 12.4.5 Buried horizontal grid
- 12.4.6 Multiple-driven vertical rods
- 12.4.7 Combined horizontal grid with vertical rods
- 12.5 Earth conductors and earth mat
- 12.5.1 Earthing conductor — considerations
- 12.5.2 Earth mat connections
- 12.6 Earthing system and earth fault current
- 12.6.1 Earthing system
- 12.6.2 Earth system impedance
- 12.6.3 Earth fault current
- 12.7 Voltage limits
- 12.7.1 Substation ROEP — voltage design limits
- 12.7.2 Transferred potential
- 12.7.3 Touch potential
- 12.7.4 Third-party infrastructure
- 12.8 Earthing design — considerations and requirements
- 12.8.1 Substation fence earthing
- 12.8.2 High-frequency earths
- 12.8.3 Indoor substations
- 12.8.4 Reactive compensation compounds
- 12.8.5 Test facilities
- 12.8.6 Earthing design method
- 12.8.7 Computer-based solutions
- 12.8.8 Standard documentation
Inspec keywords:
earthing;
fault currents;
conductors (electric);
substations
Other keywords:
power network construction;
earth mats;
earthing design considerations;
power system;
voltage limits;
substation earthing design;
resistivity;
earthing conductors;
earth electrode systems;
earth fault current;
operational performance
Subjects:
Power transmission lines and cables;
Substations;
Power system protection