Protection studies

TNEI provides protection coordination and setting studies for a wide range of sites. We have extensive experience in performing these studies for renewable generation sites such as wind farms, solar parks, biomass, STOR, etc. as well as industrial sites, such as oil platforms, large mills and factories. These protection studies consist of calculating the required settings for a commissioning engineer to enter into the protection relays on site. The calculated settings are optimised to provide the best possible coordination and balance between sensitivity and stability under transient conditions.

As part of these studies, we consider equipment damage curves, transformer inrush, minimum and maximum site fault levels. Site specific philosophies and distribution network requirements are taken into account when creating relay grading curves. Typically most sites require coordination with the upstream distribution settings.

Settings can be provided for the following types of protective device:
  • Unrestricted overcurrent and earth fault (non-directional)
  • G59/2 loss of mains 
  • Bus-zone 
  • Transformer Differential and Restricted Earth Fault 
  • Cable Differential
  • Neutral Voltage Displacement
  • Distance protection
  • Negative phase sequence
  • Directional overcurrent and earth fault protection.

TNEI can also provide assistance with the specification of protection current transformers and provide a review of existing protection schemes.


For more information on our power system protection coordination studies, please get in touch