The ever increasing penetration of distributed Renewable Energy Systems (DRES) into the electricity distribution network entails significant challenges for the Distribution System Operators (DSOs). Such challenges emerge due to the transition from the traditional architecture whereby power flows from centralized production to the loads at the edges of the grid to a new architecture whereby bidirectional power flows happen on the lines, due to the presence of DRES.
Digitization allows DSOs to apply technology-driven responses to such challenges. As distribution systems gradually become digitized, the DSOs' operations' centres evolve on parallel to take on new roles to manage and control them.
Various digital tools serve this evolution, performing a variety of functions, indicatively related to power quality monitoring; fault detection, isolation, and service restoration; voltage variance optimization, spatio-temporal electric load forecasting; generation and flexibility forecasting, etc. Tools related to the techno-economic analysis of grid expansion and network planning can also be present.
This results in an IT ecosystem with numerous building blocks, resembling to the notion of a toolbox. Such a toolbox can be built upon a modular architecture enabling the introduction of and integration with components that realize specific applications and services for the DSOs. Such business intelligence tools are part of the Domain Applications layer (see Figure 1).
The applications are facilitated by an Integration Platform enabling access to grid monitoring information stemming from the legacy DSO infrastructure through standard and secure interfaces. The Integration Platform also enables the creation and management of service composites, enabling the cooperation among domain applications.
Finally, the Presentation layer provides a "mash up" of the tools of the Domain Applications layer, enabling monitoring and alerting as well as user intervention in the workflow.
No matter the level of intelligence of IT solutions that are used by the DSOs to tackle certain problems of their business domain, a persisting challenge is that of integration and interoperability among such solutions. In many cases the DSO's IT ecosystem is composed of many different legacy systems and subsystems, rather than a monolithic Distribution Management System (DMS). In such context, the need for an information exchange bus emerges. And, ultimately, there is a need for integration of the decision support functions (business intelligence layer) with the actions’ execution functions (control plane).
Our Integration Platform addresses exactly these needs. It serves as a standards-based secure integration mechanism, providing also storage of / access to data that are fed by third party systems, making them available to the different business applications of the toolbox.
From a software architecture perspective the microservice paradigm is applied for the design of the solution. Following this paradigm, a collection of light-weight, loosely-coupled services is utilized – each one offering a single business capability. This offers great scalability, modularity as well as the capability of decentralized governance (implementation decisions).
The main design elements of the Integration Platform are the following:
Acts as a single-entry point for all clients as well as an edge service for exposing micro-services to the outside world (through the Integration Platform API). It acts as an intermediate in all incoming communications and routes them towards the respective components of the Integration Platform. Also, it provides handling of authority validation (via integration with Security Server).
It exposes the interfaces of the microservices to the routing engine as well as their operational status. It provides core functionalities related to service discovery; service routing information; and service monitoring and management.
It comprises a security infrastructure offering authentication, authorization and accounting functionality and enabling the control of access to the network resources.
It provides service scheduling and orchestration for the implementation of different business flows.
It comprises an application offering an autonomous business capability exposed through a REST interface, via the API Gateway, while being also able to invoke services of external systems. For data-related functions the Microservice is responsible for transforming the incoming data to the Canonical Data Model.
Different data stores can be used as repositories for persistently storing and managing collections of data stemming from different legacy systems and third party applications: Indicatively we refer to relational databases for storing data closer to a relational model (e.g., smart meter asset information); time series databases for storing the various sensing data and results of applications that are in timeseries form; and triplestore (or RDF store) for storing IEM CIM data in their native format.
The presentation layer of the toolbox aims to provide Graphical User Interface (GUI) for the DSO’s personnel, via a “mash-up” of the different tools of interest for the DSO. This solution reliefs the user from the problem of interacting with multiple user interfaces (of even different tool providers) enabling access to their functionalities in a single environment.
An integral part of presentation layer is a central dashboard where the user can monitor the status of each application. For real-time applications a notification interface is supported alerting the user about new events and facilitating the decision making. Dedicated user interfaces are provided for each tool of the toolbox, following a different design pattern depending the type of application (e.g. planning or operational functions). Whenever meaningful we utilize reusable components enabling presentation of info into relevant domain contextual information. For example, for the presentation of grid planning or operation info we use network graphs representing the model of the grid. Such graphs can be visualized on geographical maps or plotted via a layout algorithm (single line diagram form), overlaying relevant info (e.g. power quality events, congestions, faults, feeder isolation).
"DSO Toolbox" is the codename of a collaborative research project co-funded by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH–CREATE–INNOVATE (project code: T1EDK-00450). In this project, Intracom Telecom is the Coordinator and collaborated with a research laboratory from the National Technical University of Athens (NTUA) which designed and implemented a set of tools for techno-economic analysis of distribution network expansion and planning; distribution grid flexibility forecasting; spatial load forecasting; power system operation in emergency situations (self-healing); and, power quality monitoring. Our Integration Platform enables the integration of these tools while our Presentation Layer provides an interactive dashboard for the visualisation of the severity, localisation and timeline of daily domain events (e.g., faults, critical events), their relation to grid’s assets and mitigation actions planned by the applications of the DSO Toolbox. Indicative screenshots of the dashboard are presented in Figures 2-5.