HVDC: The future of ancilliary services?

What are the best ways to connect between different electricity grids? The changing mix of the electricity system and the advent of long-distance links sent grid companies back to HVDC technology. Now its providers suggest it could have many more advantages for grid operators. New Power’s Janet Wood caught up with Athanasios Krontiris, ABB’s product manager for HVDC about how the technology’s offer is set to expand to ancillary services.

This is an extract from an interview in the January issue of New Power Report. Subscribers can read the full interview by clicking here and logging in. Not yet a subscriber? New Power is a specialist report for anyone with an interest in the UK energy industry. We look in-depth at all the issues that have to be addressed to rebuild our industry – moving from our centralised high-carbon power system to one that will provide heat and power securely, affordably and with minimal carbon dioxide emissions. Contact [email protected] to find out more.

Krontiris argues that in combination with a grid management system, HVDC, and the semiconductors that are the core of HVDC Light version, can provide fast-acting grid services based on its micro-second response time and the ability to control the system.

“Previously the best stability came from larger grids,” he says. But as the synchronous system becomes very large – and the European market is set to add the Baltic grids into a synchronous system that reaches across the continent – the system becomes more difficult to control.

That is where an HVDC connection can help, Krontiris says, because it can provide frequency support and, in the newest versions, voltage support as well. It is tapping into power from adjacent markets, and software control allows it to ‘ramp up’ much faster than thermal plant.

ABB even proposes using the link for ‘black start’ in the event of major power outage, using the same microsecond-level control of active power. That option was tested using the link to an otherwise isolated island off the Finnish coast and power was brought back successfully within a few minutes.

Finally, ABB argues that the ability to finely measure electrical flows around the HVDC Light link means that parts of the AC network in the vicinity are much more visible to system operators. That visibility means that cables considered likely to be overloaded can be operated closer to their limits, increasing their effective capacity.

These services are not sufficient financial incentive to build an HVDC connection within a network, Krontiris says, but where a connection exists – such as the onshore converter station for an offshore wind farm – they can be offered in competition with other grid service providers such as batteries or demand side response.

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