Why building an 'active grid' is the key to renewable energy management

Australia’s national electricity distribution networks are experiencing a rapid and fundamental transformation. A rise in domestically generated power is causing disturbances in the network that go from voltage rise to rapid shifts in demand and, ultimately, to two-way flows of energy through infrastructure that was only ever designed for one-way distribution.

If not effectively coordinated, these new disturbance patterns have the potential to completely disrupt the operation of the networks and have a detrimental impact on the quality of service delivered to customers.

Historically, changes in demand have been solved through investment in additional generation, transmission and distribution assets. However, this is not going to overcome the challenges now being faced.

What’s required is a capability for more dynamic network management that can deal with frequent changes in both the instantaneous supply and consumption of power. The infrastructure that’s capable of achieving this has been dubbed the ‘active grid’.

A shift in control

An active grid leaves behind current centralised control architectures in favour of a distributed and coordinated control, based on three main principles:

• Dynamic and adaptive: An active grid should be able to dynamically adapt to rapidly changing conditions and demands.
• Flexible and interoperable: An active grid needs to integrate into the existing power distribution network infrastructure across all voltage levels as well as end customers.
• Intelligent: The dynamic monitoring and control of the active grid requires the management and evaluation of vast amounts of data to support control actions in real time, to adjust the operation parameters according to the working conditions.

The dynamic control and monitoring of an active grid infrastructure cannot be achieved by following the traditional strategies of centralised control, even if this is supported by analysis and optimisation tools.

Rather, an active grid must operate in the same way as the human nervous system. It should be able to assess risks to its operation directly where changes occur, automatically reacting if needed to avoid damage and failures.

Shifting grid monitoring and control from traditional central dispatch centres to grid assets, such as substations and relevant customers, will allow local processing analysis of field information. As a result, the operator receives only valuable information to ensure an efficient coordination of all available resources.

The role of IoT

Available IoT technologies, together with improvements in the capacity of field devices, already allow the distribution and automation of a significant part of the analysis and control functions across different grid levels. An active grid should make use of IoT technologies in a distributed architecture, including:

• Industrial IoT to allow the scalable, secure and reliable coordination of hundreds of thousands of devices deployed across the network infrastructure components.
• Edge intelligence so that connected devices capture, elaborate and react to the data associated to variable operational parameters, thus distributing data processing, analysis and control.
• Real-time integration bus where information can be published, transported and exchanged in a secure and efficient way between sensing devices, monitoring and control systems and operators in real time, and in a coordinated operation.
• Real-time and big data analytics allowing advanced grid analysis with real-time data and decision-making over models elaborated through the use of time series analysis of massive datasets.

Demand response, virtual power plants, distributed storage capacity, distributed voltage control and automatic service restoration are just the most immediate set of new services that could be monetised with appropriate market rules, through the use of IoT.

Rollouts have begun

Active grid architectures are already being piloted in a number of world electricity markets, enabling a whole set of advanced new functions.

In Europe and Asia, secondary substations are being IoT enabled to extend the grid operator monitoring and control capability into the MV and the LV levels, an area in which data is not efficiently monitored by conventional SCADA systems.

In Australia, where very high levels of solar distributed generation (close to 50% in some areas in Queensland and South Australia) are significantly affecting grid quality and reliability, the application of an active grid architecture offers operators a complete framework to coordinate in real time customer demand, generation and storage facilities.

Following an active grid strategy will ensure electricity networks can cope with the significant changes that are occurring in power flows and continue to provide reliable service to end users at all times.

Image credit: ©iStockphoto.com/Spectral-Design