New control solutions hold promise of a smarter power grid that works for renewable energy
Power grids were designed under a one-way model in which power is generated at centralised sites and sent through distribution lines to end users. The rise of cleaner energy technologies is challenging this top-down power model: by means of smart interfaces and technologies, renewable facilities and local power generation and storage sites could make the grid more reliable and flexible, enabling two-way communication between the utility and end users. While renewable energy sources disrupt grid operation in different ways, there are certain areas that need to be addressed before they can be integrated into the power grid to maintain safety and reliability. The EU-funded INCITE project was a Marie Skłodowska-Curie Initial Training Network initiative bringing together 14 doctoral students located in different parts of Europe. “INCITE sought to fill the gap between theoretical research and practical implementation of smart grid applications. Our innovative solutions and control strategies can clear the hurdles to making smart grids a reality,” notes project coordinator Jose Luis Dominguez.
Power converters and variable power: the start-up issues of a smarter grid
To safely integrate and transmit power from renewable energy sources into the power grid, operators do not just simply plug them into the grid, they use power converters. However, a large number of power converters can generate harmonics – unwanted high-frequency current and voltage components that can destabilise the system. Fast fluctuations in the amount of energy generated by renewables are another factor that can disrupt grid operation. The balance between electricity supply and demand must be maintained at all times to avoid frequency fluctuations or a blackout as the power grid has very little storage capacity. Researchers proposed both centralised and distributed control techniques to improve the converters’ control and let them interact in such a way as to stabilise the system. Use of distributed control in wind energy to optimise operation of large wind farms is a very new concept in the field. Each agent (wind turbine) exchanges information with its neighbours to produce a desired global behaviour. The control algorithms running in each agent allow it to independently take decisions with partial information about the wind farm state provided by other agents. “INCITE advanced management strategies that enable wind power plants to provide ancillary services to the power grid by ensuring the optimal loading state of each wind turbine,” explains Dominguez.
Smart solutions to manage a complex network
Different resources in the grid have different characteristics and their actions have a huge impact on the grid that cannot be neglected. Planning and coordinating these resources amongst different entities is key to retaining their efficiency, to stability, and for protecting consumers, prosumers and flexible users against rapid price fluctuations. Researchers proposed control solutions for efficient monitoring and protection of the network. In particular, they proposed methods to determine the best location of smart sensors in the network to obtain an accurate picture of the grid and therefore ensure the energy exchange is performed in the smartest and more cost-efficient way. Smart sensors can also increase the accuracy of fault detection. INCITE’s novel control strategies for retaining stability, reliability and secure operation of power grids are in line with the project motto ‘making the grid smarter’.
Keywords
INCITE, power grid, renewable energy, smart grid, power converter, distributed control, wind turbine, smart sensors