When we plug in an appliance or flick a light switch, we take it for granted that electricity will flow safely and reliably. Industry and businesses, too, expect power to be available on demand. Yet the high-voltage electric power transmission network across Great Britain, owned and operated by National Grid plc, is today an ageing system. Computational models to optimise its efficiency are becoming increasingly important. OCC is working with National Grid to provide the innovative software solutions its operators and engineers need to make the decisions that keep power flowing.
“The National Grid’s transmission system was set up in the 1960s and 70s, with a lifetime design of about 50 years,” explains Reynold Greenlaw, OCC’s Innovation Delivery Director. “It was built to handle the output from big power stations, but is now facing two major challenges. One is how to manage the power that will increasingly come from clean, renewable but somewhat unpredictable energy sources like wind and sun – and will at times result in reverse flow back into the grid. The other is how to make more efficient use of spare capacity – putting as much current through the system as possible. This requires understanding in great detail exactly what is happening in components such as transformers and cables, and using numerical modelling to achieve safe load limits.”
National Grid’s ‘Gone Green’ scenario predicts that in the year 2030 the UK’s total power demand will, at 360 TWh, be much the same as today, but around half of that will be supplied by renewables, primarily wind. Forecasting how future energy needs and markets will develop in Europe is an area of expertise for Pöyry Management Consulting. Pöyry chose OCC to develop the user interface for its complex technoeconomic BID3 power market model, which is used by National Grid.
“Being able to monitor and manage the grid is absolutely key,” says Reynold. “Since it was built we have seen huge leaps forward in IT, with advances such as telemetry, dynamic modelling and big data manipulation – all game changers.”
OCC has been helping the National Grid model the thermal behaviour of the components in its system since the late 1990s, answering questions such as: by how much can you increase the current through a transformer if you need to reroute a circuit? And for how long? Now, OCC’s next-generation TRALC3 tool is set to provide answers for more sophisticated transformers and much more complex scenarios.
OCC has also worked with National Grid on modelling underground cables. In urban areas, cables are increasingly being buried in tunnels, with air blown through the tunnels to keep the cables cool. “Calculating the capacity of a cable in an air-cooled tunnel,” says Reynold, “and then modelling what happens to temperatures when it’s joined to another tunnel, and then another tunnel comes in further along … that’s a really interesting problem.”