Smart Asset Monitoring (SAM)

The high penetration of Distributed Generation (DG) on the Northern Ireland network has resulted in the network becoming increasingly constrained.

NIE Networks' Smart Asset Monitoring (SAM) project will help address network issues and defer capital expenditure of upgrading distribution assets. The SAM project aims to determine the thermal capacity of network assets during different weather conditions, facilitating increased loading of assets without the need for high cost network reinforcement.

In summary, the project will address two areas:

1. Real Time Thermal Rating (RTTR) of 33kV overhead lines

Overhead lines (OHLs) are thermally rated based on static P27 ratings which are usually based on pessimistic weather conditions e.g. low wind speed and high ambient temperature. Whilst this approach has been successfully utilised by network utilities for a long time, studies show there is potential to enhance the rating of some overhead lines if the real-time thermal ratings are taken into account. Weather conditions vary in time and therefore assets will have a time-varying thermal rating which can be above their static thermal ratings. For example, at a high wind speed the overhead line conductor can dissipate more heat through convection to the surrounding environment. This project will consider whether we can leverage this “wind cooling” effect to implement improved line ratings and defer capital investment in overhead line upgrades to facilitate additional connections.

RTTR Objectives

The key objectives of RTTR of OHLs are:

  • Improved utilisation of network assets
  • Defer capital reinforcement on 33kV overhead lines
  • Facilitate increased loading of assets
  • Provide learning for future OHL routing and conductor sizing
  •  Assess the impact on existing assets including lifespan and maintenance requirements

2. Enhanced thermal modelling of primary transformers

Due to the connection of generation on the distribution network many primary (33/11kV)  transformers are operating in reverse power flow. This project will implement enhanced thermal modelling of primary transformers using historic data including winding temperature indicators (WTIs), with the view of identifying the forward and reverse power flow ratings at different weather conditions.

Transformer Thermal Modelling Objectives

The key objectives of this project are:

  • Improve utilisation of primary transformers
  • Analysis of the continuous transformer rating in both forward and reverse power flow
  • Provide learning and recommendations for short-term overloading of the transformers
  • Assess the impact on transformer lifespan and maintenance requirements

Work Completed to Date

  • Ricardo awarded consultancy contract to support the project
  • Technology assessment complete
  • 3 trial sites selected

Project Timeline


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