Modelling high-voltage transformers National Grid chose OCC to develop and support TRALC2, a desktop application that models the performance of high-voltage transformers as they are subjected to heavy electrical loads.

Transformers act as bridges between the high-voltage national power network and local electricity distribution. As current passes through the transformer it heats up, undergoing ‘thermal stress’. Under most conditions, it is this thermal stress that limits how much power a transformer can take.

If thermal stress reaches a critical level, a transformer will automatically cut out. This either interrupts the power supply or increases the load on other transformers in the circuit.

Software predicts thermal stress

TRALC2 allows National Grid to model the thermal stress on their high-voltage transformers under given conditions and predict when operating and safety limits will be reached. Non-steady-state modelling is required, as transformer load can vary on a minute-by-minute basis.

TRALC2 is a Windows application accessing a shared database of transformer and load data and running on the corporate desktop environment.

The application can be used live to predict the performance of circuits in the next hours or minutes. It can also be used months in advance to simulate the effects of planned maintenance.

Long-lived success

OCC delivered the first version of TRALC2 in 2000 and it is still being used, extended and supported. Recently, OCC integrated the TRALC2 model into its redesign of the National Control Room’s Circuit Thermal Monitor.

National Grid is the largest privately owned, independent transmission company in the world, and one of the top 100 companies in the UK. It owns and operates the high-voltage electricity transmission system that carries power from generators to suppliers across England and Wales. It also owns and operates transmission links to Scotland and France and plays a vital role in enabling the wholesale trade of electricity on behalf of the electricity market.