Methodologies and tools for evolving DSO roles for renewable energy integration in distribution networks

evolvDSO has investigated the future roles of DSOs in Europe’s electricity system, writes Jaime Andres Rodrigues Perez.
Published: Thu 29 Sep 2016

With the growing relevance of distributed renewable energy sources (DRES) in the generation mix and the increasingly proactive demand for electricity, power systems and their mode of operation need to evolve.

The evolvDSO project has defined future roles of distribution system operators (DSOs) on the basis of scenarios which will be driven by different DRES penetration levels, various degrees of technological progress, and differing customer acceptance patterns.

The evolvDSO consortium addressed the main research and technology gaps that need to be solved for DSOs to efficiently fulfil their emerging and future roles in the European electricity system. The new tools and methods encompassed a wide array of DSO activities related to planning, operational scheduling, real-time operations and maintenance.

evolvDSO is unique in that it has brought together the key actors of the electricity value chain that are at the forefront of smart grid development, and with a clear common view on what is needed for further DRES integration in Europe. The consortium consists of 16 partners including DSOs, TSOs, renowned research institutions and new market players that provided unique expertise to achieve the stated objectives.

The current progress towards a smart grid environment requires an active distribution system approach, taking advantage of new flexibility options and implying an active role of DSOs.

Figure 1 - Current European DSOs landscape concentration

The future roles of the DSO

In evolvDSO a set of possible future roles for DSOs were identified. These roles focus on activities of paramount importance for the implementation of an active distribution system management approach.

New roles

The High (new role) level refers to the creation and definition of new roles. A new role is defined when a new activity and corresponding responsibility is envisioned. The adoption of this role might require a longer period of time and higher complexity for implementation compared to other roles.

At this level a new role is the Distribution Constraints Market Officer, who has the capability to contract flexibility resources, based on the needs of the DSO. Local flexibility offers made by flexibility operators (e.g. aggregators) can be procured in the long and short term.

Evolving roles

The Medium (evolving role) level refers to an evolution of existing roles and responsibilities, due to the changing environment and new opportunities. A role is evolving when current practices to take up certain responsibilities need to be re-defined.

Four evolving roles are defined.

Neutral Market Facilitator/Enabler supports market participation of resources connected to the distribution grid. This is done through pre-qualification and by implementing a transparent instrument (traffic light) to assess the grid status in concert with potential market actions.

Contributor to System Security exchanges network planning and operational data, and coordinates actions on transmission and distribution grids with the TSO. The role provides possible cost-efficient local solution options to system wide problems, by responding to the TSO’s planning, scheduling and security requests.

Distribution System Optimiser improves development, operation, and maintenance of the distribution network. A cost-efficient network planning and management of grid constraints (including emergency events) allows cost-effective and non-discriminatory access to the grid.

Data Manager handles metered, contractual and network data. Performs collection, validation, analysis, archiving of historical records. Provides data originating from meters, network monitoring and sensing devices, and contracts.

Extended roles

The Low (extended role) level relates to current roles and existing responsibilities. The concerned activities can be extended but need no re-definition or complete new processes.

Roles that fall into this category make use of new technologies to enlarge the reach of DSO services and activities. Three roles are identified.

Figure 2 - The future roles of the DSO

Smart Meter Operator administers the smart metering infrastructure. The role takes care of physical meters from installation to maintenance to decommissioning. Management activities also include the information flow between the metering infrastructure and the database where data is stored.

Customer Relationship Manager (CRM) manages diverse contracts and requirements including grid users’ connection and access. The CRM also manages legal arrangements with retailers/suppliers and BRPs.

Other Third Parties Relationship Manager (OTPRM) provides basic and advanced services. This role, however, focusses on another set of stakeholders (not “grid users” in its strict meaning). The OTPRM manages the communication with regulators, conceding and local authorities, service providers and other third parties. The role provides data required by national legislation.

DSO tools developed

The system use cases represent the most innovative functionalities covering the different domains. This work allowed the evolvDSO project to develop innovative tools based on the future DSO’s roles and business processes previously identified.

Operational planning tools

The operational planning domain is divided by MV and LV networks. For the MV networks the following tools were developed.

Robust Short-Term Economic Optimization tool is an application, based on several algorithms, which fulfils completely the short-term optimization of distribution network; it is capable to detect constraints violations and solve them through the least expensive set of actions.

Network Reliability (Replay) tool is a field-oriented application which focuses on the investigation of grid management. Its main purpose is to perform a pro-active analysis of grid control actions by the means of an off-line fully operational SCADA platform. Its main goal is to analyze past events and actual real data and re-simulate them for improving grid management policies, as well as new software/hardware technical solutions testing and operators training.

Contingency simulation (co-simulation) tool selects and simulates realistic contingencies in order to identify suitable levers and, as a consequence, corrective actions and policies to solve them in the more efficient and effective way. The time horizon spans from short term to day-ahead, i.e. from 72 to 24 hours before the considered period.

For the LV networks, the following tools were developed:

State Estimation for LV Networks tool is an algorithm capable to predict the state of the system by making use of historical data and a low number of real-time measurements from smart-meters. The overall goal of this tool is to detect in the most accurate way the state of networks where topology is partially unknown (LV networks in most cases), using all the information available.

Voltage Control for LV Networks tool is capable to manage all the controllable grid assets in order to provide a close-to-real-time solution to cope with voltage deviations in LV grids. Its output is a set of control actions, in the form of set points, which enables a coordinated operation of all the available DERs.

Network planning tools

For the network planning domain, the following tools were developed:

TOPPLAN - Long Term Topologies Using Stochastic Modelling tool covers the longer time horizon (more than 30 years) and the uncertainties are modelled by using the approach of fuzzy-logic. It identifies cost-effective solutions, such as reinforcement, dedicated feeders and new substations, or solutions that enforce the flexibility of the network as reconfiguration, VVC, load control.

FLEXPLAN - Short-term network reinforcements considering flexibilities and ICT reliability tool covers the shorter time horizon (i.e. 5 to 10 years in the future) and considers scenarios for the modelling of uncertainties. The applied methodology demonstrates a new method for finding relevant network planning cases. Based on the planning cases an optimal combination of network reinforcements and the usage of flexibilities are determined to solve congestions in the network.

TSO-DSO cooperation tools

Two tools contribute to the TSO-DSO cooperation domain:

Sequential Optimal Power Flow tool derives a set of control actions that keep the active and reactive power flow within pre-agreed limits at the primary substations level (or TSO-DSO interface).

Interval Constrained Power Flow tool estimates the flexibility range in each primary substation node for the next hours and includes the flexibility cost. This tool enables an evaluation of the DER aggregators’ impact on the transmission network and provides means for a cost/benefit evaluation of the available levers.

Maintenance tool

For the maintenance domain one tool was developed.

Advanced Asset Management tool is composed by two sub-tools, one focused on asset renewal planning and the other on identifying the most critical components in a network area. The overall goal of this tool is to give distribution network engineers usable insights on each component’s role in a distribution network.

Jaime Andres Rodrigues Perez is responsible for the dissemination activities of evolvDSO. After working as an energy scheduler for the Italian electricity park in ENEL Produzione he has been involved since 2013 in several EU FP7 projects (e.g. ADVANCED, Meter-On).

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Further reading

evolvDSO project

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