Circuit Thermal Monitor
About National Grid
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, and this requires not only constant monitoring of each circuit but live calculation of the capacity of the grid, ensuring it stays within operating limits.
System Overview
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 project takes those models and moves them into the National Control Centre where they constantly monitor every circuit, calculating remaining capacity and raising alarms if components depart from safe limits.
The National Grid Network Planning department also use the Circuit Thermal Monitor, either with live or archive data, to model how the network will respond under different contingencies, from emergency management through maintenance planning to future network design.
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.
System Models
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.
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 hot spots and an indication of the time available to resolve any over loading. Since the Circuit Thermal Monitor performs continuous calculations, should an emergency outage 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.
