- Hanne Sæle
- Research Scientist
- 901 74 048
- Energy Systems
- SINTEF Energi AS
Interaction DSO/TSO (WP3)
The objectives of WP3 are to develop concepts and solutions for utilizing flexible resources (DER = Distributed Energy Resources = Energy storage, distributed generation from renewable sources and demand response) indifferent market products and ancillary services, for increased observability between the distribution and transmission systems and business models regarding utilisation of customer flexibility.
The expected impact from these objectives is improved interaction DSO-TSO to benefit the total power system, especially by enabling DER flexibility to all voltage levels.
- Ancillary services – needs and requirements
- Increased observability between distribution and transmission system levels
- Business models for utilization of customer flexibility in the interaction DSO/TSO
- Improved plans for defence and restoration
Operation – today and in the future (2030/2040)
In the beginning of 2018, a survey was sent out to the DSOs in CINELDI, with the objective to map the status of interaction DSO/TSO and the use of flexible resources in the operation today, and input related to what is expected in the future (2030/2040). To be able to discuss the transition towards this long-term period, the assumed starting point has been a survey mapping today’s status and future expectations about the DSO/ TSO interactions, and focusing especially on how and how much flexible resources are and will potentially be utilised in the power system operation and also on what kind of information it is necessary to monitor. According to the survey, the use of flexible resources today is mainly related to disconnection of unprioritized demand units that have an agreement for disconnection through a reduced grid tariff. Typically, these loads can be disconnected for an unlimited period (disconnected in periods with temporary problems with limited grid capacity), and the customers have alternative energy carriers to use when the electric load is disconnected. Based on experience, this agreement for disconnection is seldom in use. In the future, the DSOs expect that there will be an increasing focus on flexible resources, and not only to be used in periods with limited grid capacity in the power system. Due to technology development combined with reduced costs for different technologies (for example PV panels, electric batteries and communication and control technologies), flexible resources are evaluated as a new source to be included in cost efficient operation of the power system. In other words, it is expected that a wider variety of flexible resources will be available in 2030/2040, and that these will also be used in normal operation of the grid. The evaluation of future use of flexible resources was combined with the suggestion from EU FP7 project ELECTRA IRP, for a future (2030+) decentralized control architecture (Web-of-Cells) for balance (including frequency) and voltage control, as opposed to the current centralized control approach typical of Transmission System Operators (TSOs).
European legislation related to the DSO-TSO cooperation
Important topics for DSO-TSO cooperation in the European legislation has been studied, in cooperation with the SmartNet project. The study is structured around the following topics of interest: Market layer, Bidding layer and Physical layer. These topics of interest were evaluated based on more than 40 different documents as position papers, strategies, roadmaps and legislation/regulation (EU Directives, Network guidelines).
Evaluation of use case (repository) and relevant mini-scenarios
Existing use cases have been evaluated, with the purpose to get an overview of use cases from other projects, covering topics relevant for WP3. 213 use cases gathered from EPRI, ELECTRA IRP and DISCERN were evaluated. Both EPRI and DISCERN refer to use case repositories, which gathers use case and sort them by topic. 86 use cases were evaluated as relevant for WP3. The use cases were sorted according to the following categories, and the number of relevant use cases within each category are presented in brackets:
1. Utilising flexible resources (DER) (21 use cases)
2. Demand response (28 use cases)
3. Flexibility bids to the market (6 use cases)
4. System services that support frequency regulation (5 use cases)
5. System services that support voltage regulation (9 use cases)
6. Congestion management (3 use cases)
7. Other system services (14 use cases)
At the end of the year work for evaluating the mini scenarios from WP6, related to the focus within WP3 was started and will be continued in 2019. This work will be basis for development of the future use cases: use of flexible resources for balancing, handling bottlenecks and voltage regulation.
Technical and practical approaches to define new DSO-TSO interaction schemes
A literature study with the objective to study and report the technical and practical approaches used in the literature to define new DSO-TSO interaction schemes has been performed. Most of the reviewed research activities focused on devising DSO-TSO joint optimal flexibility dispatching techniques. There is limited research regarding markets' influence and data privacy issues with regards to DSO-TSO interactions. The reviewed literature also indicates that there are significant numbers of demo activities testing the merits of increased data exchange between TSO and DSO. Based on the literature study, summary of the contemporary DSO-TSO interactions and the recommended future practices are presented.
2017 has been a year for start-up of the activities within WP3. The main activities are therefore related to a first workshop with the partners in CINELDI, a concept study of ancillary services and interaction DSO/TSO and recruitment of PhD students.
Workshop with partners – arranged in cooperation with WP4 and WP5 (2017-09-07)
A partner workshop was arranged in the beginning of September in cooperation with WP4 "Microgrids" and WP5 "Flexible resources in the distribution grid". The workshop was divided in two parts, where an introduction to each WP and input from selected partners were given in the first part, and group discussions related to the topics within the relevant WPs were performed in the second part of the workshop.
The results from the group discussions will give important information for the research to be done within WP3. Two groups were established discussing how flexible resources are in use today, how they can be used in near future (2020-2030) and after CINELDI (2030-2040), both for the market and in system services.
To a limited degree some flexible resources (mainly for large industry or electrical boilers) are in use in balancing services today – as tertiary reserve with response within 15 minutes, activated by a phone call from the TSO.
In the near future, there will be an increased focus on other flexible resources, but customer involvement is a challenge. The interaction DSO/TSO has to be defined, to make it possible to activate flexible resources without generating any problems for other stakeholders. This a topic that WP3 will study.
Concept study of ancillary services and interaction DSO/TSO
A concept study was started in 2017, evaluating today's ancillary services and interaction DSO/TSO. This work will be the basis for the evaluation of the ancillary services in the future intelligent and flexible power system (2030-2040). Topics to be evaluated are state of the art in Norway and other relevant countries (based on today's power system) for the interaction DSO/TSO. Present functionalities are in use to secure a stable operation of the power system, both on transmission and distribution level, and an evaluation of which problem(s) the different ancillary services should solve such as when are different services needed? When is there a problem to solve? And what should be the physical parameters to trigger the need for activating a service? (voltage, frequency and other). This study will be completed in 2018. Important experiences from the Horizon 2020 project "SmartNet" will be important input to this work, as this project also is included as in-kind to CINELDI.
A survey for mapping the status of today's interaction between DSOs and TSO in Norway has been developed. The focus in the survey will be on the use of flexible resources in today's power system and what kind of information the DSOs are selected related to interaction DSO/TSO. The survey will be sent out to the DSOs in CINELDI in the beginning of 2018.
Two PhDs were recruited to WP3 in 2017, focusing on the following topics:
Distributed and hierarchical dynamic state estimation for smart distribution grids
The PhD will study accurate monitoring of the power system, while handling (or avoiding) the 'data deluge'. At substation level, detailed dynamical models will be utilized, with full utilization of sensor data. Information transmitted to higher voltage levels of the power system will be filtered to focus on information and system services of relevance to those higher levels. Methodology will need to be developed for sensor selection and placement for observability at the lower level, and for filtering and data fusion under consideration of the particular dynamic phenomena to be observed at higher levels.
Techno-economic optimization for analysing consumer flexibility and related market structures
The main objective of the PhD project is to develop models, concepts and solutions for utilization of customer flexibility in the energy system. This includes realization of balancing services and flexibility services as an alternative to grid reinforcement, minimizing grid asset investments and maintenance costs. The project will study market structures for trading flexibility, the different players, business models and decision support for the analysis of markets, contracts, tariffs and cooperation
The PhD students started up with their coursework in 2017, that will be continued in 2018. Additional, the PhD students in cooperation with their supervisors will start on the academic work related to each PhD topic.