One of the main objectives of DISCERN (cf. D 1.3) is to enable European DSOs to share their experiences gained in existing Smart Grid solutions. In that way, all DSOs involved in the project (and also other European utilities) will learn from existing solutions in order to identify the optimal level of intelligence in their distribution networks.
With the aim of achieving this goal, it is mandatory to define a common format to share the experiences gained in existing solutions. The use case templates can be used for defining this common format and therefore should facilitate the learning process in DISCERN. Besides, given that these templates are based on international standards, the descriptions of the solutions could also be reused beyond the project
Use Case Template
DISCERN considers several Smart Grid sub-functionalities that can improve the management and control of distribution networks. In order to assess, implement and, possibly, simulate each sub-functionality, it is necessary to identify the requirements of the systems that provide such sub-functionality.
The template relies on the latest version of IEC 62559-2 standard. In order to make it easier for users to represent the Use Cases, it provides lists of elements (actors, scenario types or functions, and requirement types) that should be employed in different parts of the template. These lists of elements are based on existing standards and reports, such as: IEC 61968-1, IEC 61850, the ENTSO-E Role Model, and the IEC 62559-2 standard [IEC 62559-2].
Use Case Template Structure
The DISCERN Use Case Template comprised the following points:
- Point 1: Description of the Use Case. This point provides an overall description of the Use Case, focusing on its objectives and scope; that is, mainly, which problems are to be resolved with this Use Case.
- Point 2: Diagrams. In this point, experts created diagrams that facilitate the understanding of the Use Case. DISCERN Use Case Template proposes two well-known diagrams for defining system requirements: Use Case diagram and Sequence diagram.
- Point 3: Technical Details. The technical details of the template refer to: the list of actors involved in the Use Case, the events that trigger the Use Case, the related standards and reports, and key data for classifying and comparing Use Cases.
- Point 4: Step by Step Analysis of the Use Case. It details the sequence of activities required to realize the Use Case.
- Point 5: Information Exchanged. This point summarizes the information exchanges between actors within the Use Case.
- Point 6: Requirements. Describes the non-functional requirements of the steps defined in the Step by Step Analysis of the Use Case.
- Point 7: Common Terms and Definitions. In this point experts can include specific terms key to understand the Use Case.
- Point 8: Key Performance Indicators (KPI). Finally, the DISCERN Use Case template extends the IEC 62559-3 template with one additional point for representing the Key Performance Indicators (KPI) that will be used to assess the solutions that realize the Use Case.
The following figure shows the overall process for describing and assessing the solutions that implement the sub-functionalities considered in DISCERN. It is worth emphasizing that this figure is not aimed at detailing all the tasks and interactions within DISCERN project. On the contrary, it simply highlights those tasks in which the templates are used. Moreover, it also shows where (and for what purpose) the descriptions based on the templates should be employed in other tasks. The Leader, Learner and Listener approach is described in Result#1.
Figure 1 - Interactions between leaders, learners and listeners in each DISCERN sub-functionality
For each sub-functionality in DISCERN, leaders described their solution in a technology neutral manner by using the DISCERN templates. In that way, learners received in a common format input on how these solutions could be replicated in their networks. Moreover, listeners can carry out a feasibility analysis from these descriptions in order to decide whether this sub-functionality can be adopted in their systems or not.
Leader Use Case Descriptions
The solutions proposed by Leaders were presented in the form of Use Cases and SGAM models by using the standard-based templates created in DISCERN. These Use Cases and SGAM models were grouped into the following DISCERN sub-functionalities:
For all these DISCERN sub-functionalities, Leaders’ Use Cases and SGAM models were presented and analysed. The analyses were focused on the actors and functions used in the descriptions, highlighting the proposed extensions to the available lists of actors and functions in the state of the art. This resulted in a first assessment of the existing standards (particularly the CIM Interface Reference Model defined in the IEC 61968-1 standard) in the context of DISCERN solutions. Moreover, the refined lists of actors and functions is a first step towards the definition of consolidated lists (or taxonomies) that could be reused beyond the project with the aim of facilitating knowledge sharing among European DSOs. The Tables below show the new actors and functions which were proposed.
Table 1 - New actors proposed by Leaders
|Automatic Tap Changer Controller||Device or application which operates the tap changer automatically according to given set points or by direct operator commands (manual mode).||X|| || || |
|Battery||One or more cells fitted with devices necessary for use, for example case, terminals, marking and protective devices.|| ||X|| || |
|Battery Controller||An IED that provides data about battery status and controls the charging/de-charging cycles|| ||X|| || |
|Current Sensor||Devices, which are spread on the Grid lines, continuously reporting dynamic status of current||X||X|| || |
|Data Repository||Data repository for data archiving, analysis or reporting purposes|| ||X|| || |
|Demographic Data Provider||Third party provider of demographic data associated with properties within a geographic area, e.g. local council|| ||X|| || |
|End Point Monitor||A monitor of electricity not used for billing purposes and deployed by the DNO for the purposes of LV visibility of per-premises consumption|| ||X|| || |
|Fault Passage Indicator||Device that indicates the presence and direction of a fault current in the cables where the device is located||X|| || || |
|Investigative Analysis||External actor responsible for creating and undertaking analyses providing conclusions that may inform future business strategy decisions. These analyses include but are not limited to: modelling, statistical analysis, comparative analysis of options, or generation of forecasts.|| ||X|| || |
|IT||Actor providing IT systems support & maintenance and custodians of digital data inc. storage, access levels & IT security|| ||X|| || |
|LV Grid||Low Voltage (LV) distribution network. Process actuators (e.g. Switch or tap changers) and sensing devices (e.g. current sensors or voltage sensors) within the network are represented as separated Actors.|| ||X||X|| |
|MDM Operator||Operator of the MDM system|| || ||X|| |
|MV Grid||Medium Voltage (MV) distribution network. Process actuators (e.g. Switchs or tap changers) and sensing devices (e.g. current sensors or voltage sensors) within the network are represented as separated Actors||X|| || || |
|Operation Controller||Automation system located at operation level (typically in the network control centre of the DSO) monitoring and controlling the devices in the network|| ||X|| || |
|PER Operator||Operator of the PER system|| || ||X|| |
|Performance Evaluation Reporting Database||Application and database to handle the events, alarms and to follow up the collection performance of meter readings, according to the terms and conditions in the data collection service contract|| || ||X|| |
|Power Analysis Tool||Application used to undertake power system analyses, including: power flow analyses, generation of energy profile data, simulation, etc.|| ||X|| || |
|Switch||A generic device designed to close, or open, or both, one or more electric circuits.||X||X|| || |
|Switch Controller||An IED that controls any switchgear. It enables the control from remote centers (tele-control) and also from related automatics. It supervises the command execution and gives an alarm in case if improper ending of the command. It can also ask for releases from interlocking, synchrocheck, autoreclosure if applicable|| ||X|| || |
|Systems Interfacing Support||Actor responsible for delivering & ensuring functional system interfaces|| ||X|| || |
|Tap Changer||Mechanism for changing transformer winding tap positions||X||X|| || |
|Voltage Sensor||Devices, which are spread on the Grid lines, continuously reporting dynamic status of voltage||X||X|| || |
Table 2 - New functions proposed by Leaders
|Network Operation Monitoring||Harmonics and Interharmonics||To acquire values from CTs and VTs (or other sensing devices) and to calculate harmonics, interharmonics and related values in the power system mainly used for determining power quality|| ||X|| || |
|Network Operation Monitoring||Sequences and Imbalances||To acquire values from CTs and VTs (or other sensing devices) and to calculate sequences and imbalances in a three/multiphase power system|| ||X|| || |
|Network Operation Monitoring||Monitoring Optimisation||Identify optimal monitoring deployment level for effective observability by analysing & aggregating monitoring data from various sources and assessing results for comparability and/or using Customer Profiling data for given sections of the distribution network|| ||X|| || |
|Network Control||Automatic Controls||Automatic controls, functions to optimize network operation, such as: automatic tap changer control, automatic voltage control, reactive control, load shedding busbar change, etc.||X||X|| || |
|Network Operation Calculations||Network Operation Calculations||Identify patterns in the historic load data, whether temporal or spatial, individual or aggregated, etc.|| ||X|| || |
|Advanced Metering Infrastructure||AMI Event Service Management||Provides information on a specific meter or meter group for a particular event. It acts as a gateway to communicate between utility enterprise systems and field devices (mostly AMI meters) through AMI network. Allows customer service representatives and other business personnel to query specific devices to resolve issues in a short period of time (but not in real time)|| || ||X|| |
|Advanced Metering Infrastructure||AMI Alarm Supervision||Supervision of alarms indicating AMI failure|| || ||X|| |
|Metering System||Meter Power Switch On and Off Commands||Function to switch on/off a meter|| || ||X|| |
|Metering System||On-demand Meter Readings||Function to get on-demand readings from meters|| || ||X|| |
|Metering System||Meter Data Management||This function collects, validates, stores and distributes readings and event-related data from meters and other end devices to other enterprise functions and systems. The meter data management function supports diverse end-use applications including but not limited to billing, load management, load forecasting, demand response, outage management at distribution level, asset management and distribution network planning and maintenance|| ||X|| || |