Monitoring the national electricity grid

Enables effective maintenance and better planning

Generates live predictions of circuit capacity 

National Grid owns and maintains the high-voltage electricity transmission system in England and Wales. Engineers at the National Control Centre in Wokingham are responsible for balancing national supply with demand on a minute-by-minute basis.This requires not only constant monitoring of each circuit but live calculation of the capacity of the grid, ensuring it stays within operating limits.

Modelling critical capacity

Since 2000, OCC have been supplying software models to National Grid which calculate the capacity of critical components in the network. The Circuit Thermal Monitor runs those models in the National Control Centre where they constantly monitor critical circuits, calculating capacity and raising alarms if components approach safe limits.

The National Grid Network Planning department also use the Circuit Thermal Monitor to model how the network will respond under different contingencies, from emergency management through maintenance planning to future network design.

OCC, National Grid and GE

Work started in 2006 with OCC consultants working with National Grid IT and engineering staff to capture requirements and resolve the high level design. An additional challenge was that the project team had to develop and deliver the new software as part of a larger Control Centre upgrade by General Electric. This necessitated close working with GE staff in Shanghai and Florida to guarantee compatibility both in implementation and project milestones - this was a project that could not slip.

Designing, developing and testing

Through 2007-2009 the OCC team designed, developed and tested models which calculate the changing temperatures and electrical capacity of critical components (most importantly transformers and cables) in a manner compatible with the National Control Centre infrastructure and the GE software upgrade. In autumn 2009 the integrated system went live and the Circuit Thermal Monitor was operational.

The Circuit Thermal Monitor is implemented in C++ and Fortran and runs on a Unix platform.

Control  room receives automatic estimates of capacity

Today, the engineers responsible for managing the national electricity supply can see up-to-the minute calculations of the capacity of circuits on the  grid, identification of hotspots and an indication of the time available to resolve potential overloading. Since the Circuit Thermal Monitor performs continuous calculations, should an unexpected failure occur, the system automatically updates the control room with new capacity and time estimates.

With better tools for modelling, National Grid can undertake more comprehensive planning of the capacity and resilience of the network.