ACTIVE GRID – A control Architecture for the transformation of the electrical system.
The distribution of electricity is undergoing a fundamental transformation, driven by changes in the customers connected to the grid.
Renewable distributed generation and storage technologies are providing end-customers with tools to improve their energy efficiency becoming more autonomous. Simultaneously these energy capabilities distributed across the grid, if not coordinated, have the potential to completely disrupt the operation of the grid and the electricity markets impacting grid quality of service and robustness as well as grid services.
Historical changes in demand, have up to now, been solved through investment in additional generation, transmission and distribution assets.
As our society becomes more dependent on electricity supply and economic pressures increase on grid operators, the options to solve these adverse impacts on the grid and markets are strongly limited if we follow traditional approaches.
All these transformations are driving us towards distribution grids increasingly more complex and dynamic with many more actors impacting its design and operation.
Figure 1. Fundamentals of the transformation of the Grid
The technologies and architectures currently used to monitor and control electricity Grids and Markets have not been designed to operate under this challenging conditions and start to find difficulties to cope with this increasing changes in the form of performance problems or scalability costs.
The transformation of the electrical grid opens the door to new opportunities for a more efficient operation of electrical grids and markets in the form of more distributed resources, that if correctly integrated, will boost the electrical system flexibility and reliability and improve overall efficiency and sustainability.
One clear example of these benefits is the integration of all the customers’ generation, demand or energy storage flexibilities into a flexibility market where generators, operators and customers exchange services in real time automatically balancing generation and demand in the most efficient way, reducing overall costs of the electrical system and increasing its reliability.
The grid capable of meeting those challenges and attain those goals is what we can name as the “Active Grid”.
The Active Grid leaves behind current centralized control architectures, which are facing significant scalability limitations in favor of a distributed and coordinated control based in three main principles:
- Dynamic and adaptive.
The Active Grid should be able to dynamically adapt in each of the grid areas to changing monitoring and control capacities using available monitoring and control devices and control capabilities provided by embedded Distributed Energy Resources (DER).
Flexible and interoperable.
The Active Grid, to achieve an efficient and reliable operation needs to integrate into a comprehensive grid view (HV/MV/LV and the customers) all available monitoring and control resources, regardless of the manufacturer and the ownership, into a common and coordinated distribution grid operation.
To achieve this goal, the Active Grid needs to be based in criteria of secured: modularity, distributed control and interoperability.
The dynamic monitoring and control of all the grid and third party connected resources (DER) requires the management and evaluation of vast amounts of data to support control actions in real time, continually adapting to changing conditions.
This dynamic control and monitoring of a massive volume of elements in the grid cannot be achieved efficiently following current strategies for centralize control by the operator even if this central operation is supported by complex central analysis and optimization tools.
The Active grid in the same way as the human nervous system should be able to assess risks to its operation directly in the field, automatically reacting if needed to avoid further damage without having to wait for a central analysis and reaction.
The extension of the grid monitoring and control from current central dispatch centers to the grid assets (Substations primary and secondary, and relevant customers) will allow the local processing analysis of the field information, sending to the operator only valuable information to ensure and efficient coordination of all the resources without hindering his analysis with millions of simultaneous raw signals.
Current IOT technologies and improvements in field devices computing capacity allows the distribution and automation of a significant part of the analysis and control functions across the different grid levels. The Active Grid in order to achieve the proposed objectives, should exploits novel IOT (Internet Of Things) technologies in a completely data and control distributed architecture:
- Industrial IOT to allow the RT scalable, secure and reliable coordination of millions of devices (objects) in the field and DER.
- Edge Intelligence. Novel hardware and software platforms allowing Edge devices to understand and react to their current environment distributing the data processing, analysis and control.
- Real Time Integration Busses allowing for a common data space where information can be exchanged in a secure and efficient way between field devices, systems and operators into a coordinated operation. Real Time and Big
- Data Analytics, allowing advanced grid analysis and decision making over real time and massive data
The combination of all these technologies allows INDRA to define the Active Grid Architecture as shown in the following figure:
Figure 2. Active Grid Architecture
The proposed Active Grid Architecture given its modularity and flexibility allows for direct integration with existing monitoring and control devices and architectures already in use:
- Efficiently extending DSO’s current monitoring and control capabilities to the whole grid (HV, MV and LV) and allowing the integration and coordination of the end customer in the grid operation.
- Enabling a whole set of new market services such as flexibility services: Demand response, Virtual Power Plants, Distributed storage ... or grid services: Distributed voltage control, service restauration...
Proposed Active Grid architecture is already being piloted in the most challenging world electricity markets, enabling a whole set of advanced Smart Grid functions.
- Active Grid for MV/LV Monitoring
Medium and Low voltage levels is where most of the disruptions to the classical distribution model are happening.
Distributed generation, EV, storages integration, prosumers demanding active roll are all disruptions impacting mainly MV/LV levels in the grid.
It is precisely at these levels where utilities have scarce or nonexistent monitoring nor control capacity.
Extending current SCADA monitoring & control to MV/LV is proving technically challenging and expensive given the “last mile problem” which multiples the number of points and assets to manage x 1000 and the number of signals to manage by x 10000.
The application of Active grid IoT architectures provides required support to manage this massive volume of distributed sensing devices and the data produced by them.
Edge Intelligence allows ensuring the interoperability with existing and new field devices at the same time that allows processing the data in the field minimizing the volume of useless data sent to the operator and maximizing the value of the information received, in the form of aggregates, alarms or key performance indexes.
In Europe and Asia, Active Grid architecture is being piloted in secondary substations to extend the grid operator monitoring and control capability into MV and LV level where standard SCADA systems are not able to integrate this level of information efficiently.
The deployment of integrated monitoring units in the secondary substations (as shown in illustrations for a ground substation) allows DSOs in less than 15 minutes’ start receiving in INDRA’s MV/LV portal a complete diagnosis of the status of the grid.
This extended monitoring capacity is allowing operators a better understanding of the status of the grid at that level and its evolution, generating early warnings to problems, thus reducing reaction times and effectiveness of control actions.
- Condition monitoring of Active Grid assets
Once MV/LV Monitoring is enabled, the deployment of condition monitoring models in the Grid analytic layer, automatically enables the operator, monitoring the risk of failure of the most critical assets in the grid such as transformers and automatic switches.
The massive amounts of data gathered by the infrastructure related to the conditions under which the assets operate, allows building models capable of forecasting the risk of failure of grid assets before they actually happen, improving maintenance operations and grid reliability.
- New transactive models for distributed control of the Active Grid.
When the same Active Grid components used for monitoring are configured to allow the exchange of control signals with the distributed customers connected to the grid, a whole set of new functions are enabled related to the Real Time coordination of customers’ energy resources within the grid and market frameworks.
In regions such as Australia, where very high levels of solar distributed generation (close to 50%) are significantly affecting LV grid quality and reliability; the application of Active Grid architecture offers grid operators and customers a complete framework to coordinate in real time customers‘ demand (Demand Response), generation (Virtual Power Plant) or storage flexibilities.
The coordinated operation of the grid and all the distributed resources is enabled through the exchange of transactive services between customers and operators in a more efficient operation of the electrical system.
The same architecture is being applied to Micro grids supporting simultaneously the control of the grid basic quality parameters (frequency/voltage) and the overall minimization of the electricity costs.
All these different business scenarios share a common architecture in a novel approach for the distributed management of the Active Grid.