Power systems around the world are faced with a wide range of challenges in order to realize the objective to integrate an increased amount of renewable energy sources in the modern electricity grids. The consequences affect the daily operation and longterm planning of transmission and distribution systems, and the network owners and operator’s ability to ensure continuous, reliable and high quality of supply to the customers. The needs of each actor within the electrical supply chain provide drivers for revision of current practices and promotes future adaptions of functional components and systems, economic and regulatory areas.
This document provides insights in the work of ISGAN Annex 6, in form of key messages consolidated from the views of the focus areas

• Technology Trends and Deployment
• Expansion Planning and Market Analysis
• System Operation and Security
• Transmission and Distribution System Interaction

micro and MEGA represent two trends which largely influence the decisions and the evolutionary process of power grids.

The trends are both aimed at enabling very high penetration of renewable energy sources
in the electric power system, from two perspectives:

• micro focuses on local solutions, while
• MEGA focuses on system or even intra-system wide solutions

ISGAN Annex 6 has dedicated an activity to study the micro and the MEGA trends, with the objective to present a critical assessment of these trends, based on the questions:

• Does one trend outcompete the other?
• Does increased investments from one perspective increase the need for investments
  from the other perspective?
• To what extent can one perspective benefit from the other perspective?

The intention is not to proclaim one solution being superior to another, rather to provide well
informed insights to the needs of considering both perspectives during the planning
and decision-making process for the sustainable development of the wider energy
system.

The outcome of this activity are communicated through publications, presentations and workshops, with contributions from a large number of parties:

• In the Policy Brief: micro vs MEGA – trends in power system development, the condensed knowledge from this activity was published for the 11th Clean Energy Ministerial hosted by Saudi Arabia, September 2020

• In the Discussion Paper (DOI: 10.13140/RG.2.2.11569.61287), the full report is provided from this activity, including detailed insights into the micro & MEGA trends and their perspectives together with experiences from around the World.

• Workshop and meeting in Montreux
  A highly successful event, gathering a total of 30 participants, with presentations (available here) from Italy, India, Spain, Belgium, France, Germany, Norway and Sweden.
  The participants at these two meeting days have shown a high level of engagement and it has been highly valuable to learn from each other. In short, we can conclude that these meetings were very productive and successful in gathering a large amount of knowledge.

In Europe, there is a sharp increase in reserve needs for coping with the variability introduced by a steadily increasing RES share in the generation. The big challenge is to extend the possibility of providing Ancillary Services (AS) – frequency and voltage control, congestion management, etc.) to entities connected to the distribution network.
All these issues have been addressed by the SmartNet European research project (http://smartnetproject.eu/), which aimed at comparing different TSO-DSO interaction schemes and different real-time market architectures with the goal of finding out which would deliver the best compromise between costs and benefits for the system. The objective of this three-and-ahalf year project (2016-2019) was to develop an ad hoc simulation platform which models all three layers (physical network, market and ICT), analysing three national cases (Italy, Denmark, Spain).

In addition to providing information on the main results obtained by the SmartNet project, this report include some information on the status quo of the procurement of ancillary services in selected countries. A questionnaire was formulated and distributed among the members of ISGAN Annex VI. The questionnaire contained the following questions:

• What system services are provided in your country (voltage regulation, frequency regulation, inertia, support to power quality…)
• Who is providing them (generators and/or loads?)
• Modalities to collect ancillary services: via markets, contracts, compulsory non-paid services… Please describe in detail.
• Are generators and/or loads located in distribution admitted to provide system services? If yes, how is TSO-DSO interaction carried out (please describe in detail)
• Are there plans from the national regulator to activate demand side management or to collect inputs from generators connected to distribution for the future? Which timeframe? Are pilot projects already active?

Solutions providing advances in flexibility are of utmost importance for the future power system.
However, flexibility is not a unified term and is lacking a commonly accepted definition. The flexibility term is used as an umbrella covering various needs and aspects in the power system which complicates the discussion on flexibility and craves for differentiation to enhance clarity.

ISGAN Annex 6 has dedicated an activity on flexibility with the intention to support an increased understanding of the flexibility concept, proposing categorisation of flexibility needs in the power system.

This activity resulted in several publications with contributions from parties in: Sweden, Austria, Canada, France, Germany, Italy, Norway, and Switzerland.

• The final results and conclusions of this activity were presented at a dedicated ISGAN Webinar, November 2019.

• In the Fact Sheet: Grid Evolved – Power System Flexibility, the condensed knowledge from this activity, with collaboration with Mission Innovation, was published for the 10th Clean Energy Ministerial in Vancouver, Canada, May 2019.

• In the Discussion Paper (DOI: 10.13140/RG.2.2.22580.71047), the full report is provided from this activity, including description of the flexibility categories: Flexibility for Power, Flexibility for Energy, Flexibility for Transfer Capacity, and Flexibility for Voltage.

• The Leaflet: Power system flexibility – the ability to manage change presents an executive summary of the discussion paper, giving a good insight into the work. This leaflet was published for the ISGAN Conference The future of electricity markets in a low carbon economy in Stockholm, Sweden April 2019.

• The Scientific paper: Flexibility to support the future power systems, based on the discussion paper, was published for the CIGRE Symposium in Aalborg, Denmark, June 2019.

The main objective of this report is to assess the future data exchange and ICT requirements concerning the interaction of distribution and transmission networks, by identifying key challenges that deserve attention.

This report is based on a questionnaire regarding the ICT aspects of TSO-DSO interaction. The questionnaire contained questions regarding technical aspects (e.g. technical connection points between TSO and DSO in the countries), regulatory aspects, flexibility markets, drivers and barriers for TSO-DSO interaction as well as experiences from projects and lessons learned. The questionnaire was sent to the Annex partners and nine responses were collected. In particular Belgium, Germany, Italy, Finland, Sweden, United States, China, India and Austria have sent comprehensive answers.

Due to the integration of renewable energy sources, the interaction between TSOs and DSOs gets more and more important to handle the high volatility of generation and unexpected load growth in power grids. Additionally, new market mechanisms and the connected flexibilities require a closer interaction between TSOs and DSOs.

System efficiency is a multifaceted concept, which in the present document is broken down in the dimensions of carbon dioxide (CO2) emissions, energy and economic efficiency.
In order to improve the efficiency of a given system there are a number of available solutions at the disposal of policymakers and market actors. In this work, five action areas have been chosen and defined – multi-energy systems, electric storage, electric mobility, demand side management and automation & sensor technologies – and a review of activities and initiatives currently underway in several countries has been presented.
The efficiency measures and indicators identified in this report are key for bringing about the vision of an environmentally friendly and economically profitable electrical energy system, although some alternatives are not yet at a stage where they could be readily deployed in a systematic or widespread manner. In these cases and depending on the specific circumstances, regulatory policies and support measures can provide guidance and sustenance to overcome the uncertainties of future developments and promote potentially promising solutions.

In this work, the concept of a single marketplace for flexibility is introduced. Based on the requirements for TSO-DSO interaction, the concept of a single marketplace for flexibility has been assessed. This assessment does not provide a comparison with other ways to ensure a coordinated use of flexibility, but it shows the strengths and weaknesses of a single marketplace for flexibility.

The single marketplace is a lean and transparent concept to deal with the procurement of flexibility, which could theoretically lead to an economical optimum for the entire system, while respecting technical boundary conditions. On the other hand, the marketplace will not function properly without sufficient flexibility offers, there is no practical experience with this concept and the ICT requirements for its implementation are challenging.

Developed countries face problems with an aging infrastructure. Across this landscape of change, it is crucial for policy-makers to understand the synergies between grids and information and communication technologies. Only smart and strong grids will connect people with reliable clean energy.

The case book Spotlight on Smart and Strong Power T&D Infrastructure highlights experiences of countries in different parts of the world, as they performed transmission and distribution projects on their electrical systems. The projects illustrate a wide range of applications, solutions, and technologies that were used to meet the challenges that various countries were facing. Many of the projects focused on the need to manage the integration of large amounts of renewable and often intermittent energy sources.

Additional projects will be added progressively in future editions of the case book.

The first edition of the case book was published in 2015. It includes eight cases, based on information collected during 2014 and 2015.

The second edition was published in 2016 and contains an aditional five cases. Case book summaries in Spanish and English are provided for the second edition .

Energy access constitutes one of the fundamental building blocks for economic growth, as well as social equity, in the modern world.

Access to sustainable energy is needed to achieve sustainable development. This paper serves as an input document to the global discussion on how to reach the UN goal of “Sustainable Energy for All”, by sharing case study knowledge in the field. The following topics are considered through the examination of several implemented cases from different parts of the world:

• Analysis of the interaction between centralized grids and microgrids.
• Analysis of stakeholder decision parameters for electrification through extension of the central grid or microgrids; such as distance from grid, economic feasibility and environmental sustainability.
• Analysis of design differences and requirements for microgrids, based on intended purpose and the needs of the end customer.

It has been determined that good planning, appropriate requirements and clear regulations for microgrids limit the risk of stranded assets and enable better business cases for the involved stakeholders.

A synchrophasor is a time-synchronized measurement of a quantity described by a phasor. Like a vector, a phasor is a complex number that represents both the magnitude and phase angle of voltage and current sinusoidal waveforms at a specific point in time. Devices called phasor measurement units (PMU) measure voltage and current, and with these measurements, calculate parameters such as frequency, real power (MW), reactive power (MVAR) and phase angle. Data reporting rates for these parameters are typically 30 to 60 records per second, and may be higher. In contrast, current supervisory control and data acquisition (SCADA) systems typically report data every four to six seconds – over a hundred times slower than PMUs.

Measurements taken by PMUs in different locations on the network are accurately synchronized with each other and can be time-aligned, allowing the relative phase angles between different points in the system to be determined as directly measured quantities. Synchrophasor measurements can thus be combined to provide a precise and comprehensive “view” of an entire interconnection, allowing unprecedented visibility into system conditions.

The number of PMUs installed worldwide, as well as the number and type of grid operations informed by PMU data and applications, have seen notable increases in recent years. The past six years have seen a significant increase in the number of PMUs installed across North America’s transmission grid, from fewer than 500 installed in 2009 to nearly 2,000 today. This rapid increase in deployment of PMUs was spurred by the 2009 American Recovery and Reinvestment Act (ARRA), which funded federal Smart Grid Investment Grants (SGIG) and Smart Grid Demonstration Projects (SGDP), with matching private funds. In Norway, responsibility for the deployment of PMUs has recently been assumed by the Transmission System Operator’s IT division, meaning that PMUs are becoming an integral part of the grid information infrastructure for system operations.

The case book Spotlight on Smart and Strong Power T&D Infrastructure spotlights a number of projects sharing best practices to meet challenges for the power systems to become stronger and smarter.

Many different approaches are possible to meet these challenges and the regulators have a key role in supporting the development towards clean sustainable solutions.
Different countries have different challenges, will use different solutions to those challenges, and have reached different maturity in the implementation of those solutions. Smart grid solutions are also found across the entire electrical system, from the high voltage transmission grid, through the distribution grid and finally on consumer level. It is therefore no generic solution or size that fits all for the solution towards the smart and strong grid. At the same time there are generic solutions and findings from experiences that can be adapted by other countries to make local implementation faster and more efficient.

Higher flexibility in network dispatching can be achieved either by increasing the deployment of bulk storage in the transmission network, or by widening the set of resources available as a base for energy balancing. The latter strategy could potentially be actuated by allowing reserve procurement across transmission operator jurisdictions.

In a European context this strategy would be referred to as trans-national balancing; and could also be relevant to procurement across different Regions and Balancing Authorities in North America. A further positive could be achieved through participation in the balancing mechanism from generators and loads located in distribution networks. Beyond supporting dispatching efficiency, these flexibility elements make it possible to deploy a sustainable expansion strategy of the trans-national transmission corridors, taking into account the current difficulties faced in achieving public consensus for the building of new overhead lines. This report illustrates the potential of these strategies by referencing the results achieved in a number of important and ongoing European research projects.

Energy Access constitutes one of the fundamental building blocks for economic growth as well as social equity in the modern world. Access to sustainable energy is needed to achieve sustainable development.

Through examination of several implemented cases from different parts of the world the following topics are considered: i) Analysis of the interaction between centralized grids and microgrids ii) Analysis of stakeholder decision parameters for electrification iii) Analysis of design differences and requirements for microgrids, depending on the intended purpose and the need of the end customer. It is determined that good planning, suitable requirements and clear regulations for microgrids (in relation to centralized grids) limits the risk of stranded assets and enables better business cases for the involved stakeholders.

Examples of these trends are the electrification of energy consumption and the increasing volume of distributed generation being connected to the distribution grid.

The relationship between transmission system operators (TSO) and distribution network operators (DSO) is changing. Examples of these trends are the electrification of energy consumption and the increasing volume of distributed generation being connected to the distribution grid. In Europe this subject is highly relevant as pointed out by ENSTO-E (European Network of Transmission System Operators for Electricity) in their paper, Towards smarter grids: Developing TSO and DSO roles and interactions for the benefit of consumers published in March 2015, and ACER (Agency for the Cooperation of Energy Regulators) in their conclusions paper, Energy Regulation: A Bridge to 2025 published in September 2014. ENTSO-E is an association which represents 41 European TSOs and has an objective to promote closer cooperation across Europe’s TSOs to support the implementation of EU energy policy objectives of affordability, sustainability and security of supply. ACER is an agency of the European Union with the overall mission to complement and coordinate the work of national energy regulators at EU level, and to work towards the completion of the single EU energy market for electricity and natural gas. The expected increased interaction between TSOs and DSOs will result in both technical and non-technical challenges.

IEA ISGAN Annex 6 has published a discussion paper in which the current and future cooperation between TSOs and DSOs has been investigated. Six critical grid operation challenges have been identified:
1. Congestion of the transmission-distribution interface
2. Congestion of transmission lines and distribution lines
3. Voltage support (TSO↔DSO)
4. Balancing challenge
5. (Anti-)Islanding, re-synchronization, and black-start
6. Coordinated protection

For each case, country experts provided first-hand information about the status and expected development of TSO-DSO interaction in their respective countries. This resulted in an overview, by country, of the interaction between grid operators and provided input for the discussion about how this interaction could evolve in years to come. Technical aspects, as well as policy aspects, have been taken into account.
The technical solutions required for a closer interaction between TSOs and DSOs are very similar for most of the identified cases, except for the case of islanding & black-start. From a high level viewpoint, grid monitoring has to be implemented, communication between TSO and DSO has to be established and means of communication between the DSO and its flexible customers have to be available. DSOs should also be able to perform (quasi) real time network simulations with input from measurements on the grid.
Such technical requirements should not be underestimated regarding implementation and operational cost, complexity and skills required. These could be a challenge, especially for smaller distribution network operators. Nonetheless, only the distribution grid operator has information about the actual grid configuration and grid loading. This means that even when other entities take up certain roles, for example the role of aggregator, the distribution network operator will always be responsible for monitoring the grid and will need to implement communication solutions to one entity or another.
With the current status of technology, technical requirements for an evolved interaction between TSOs and DSOs can be met. However, several non-technical issues, or points of discussion, have been identified which are closely related to the regulated environment grid operators are working in.

• Maintaining a balance between infrastructure investments and use of flexibility

Flexible demand and generation can be used to support grid operation and avoid infrastructure investments. A minimum use of flexibility will be necessary to avoid over investing, but the impact on the processes and business cases of flexible customers has to be limited. The flexibility available by curtailing renewable energy sources needs to be limited to avoid a high loss of renewable energy.

• The role of markets
Which grid operation challenges should be met by introducing markets and which should be managed only by technical means and appropriate bilateral contracts? It is proposed to use market mechanisms only for the balancing challenge, which is applied today in various countries. Coping with local grid operation challenges such as critical transformer loading, line loading and voltages, is proposed to be managed by the network operators, optimally interacting with each other and using flexible customers when necessary. Because of the local nature of the mentioned grid operation challenges, markets would not work efficiently. Instead, a regulatory framework is required for bilateral contracts between flexible customers and network operators, facilitating the use of flexible generation and demand for grid operation purposes.

• Setting a level playing field for flexibility
When the combined flexibility of customers on the distribution and transmission grid is used, favoring one set of customers at the cost of the other should be avoided. For example, when facing critical line loading on the transmission grid, the use of flexibility of only distribution connected customers would be undesirable. Some mechanism, probably in discussion with the regulator, should be implemented to cope with this.

• The role of regulation
Closely related to the previous statement is the discussion point on how grid operation should evolve:
more regulated, with clearer and stricter roles, or more open, with guaranteed interaction between grid operators and new market players? There is no one size fits all solution but in any case, a clear definition of the roles and responsibilities of all participants in future grid operation will be necessary and will serve as a good start.
A clear policy framework will, in every case, push forward investments in Smart Grid solutions to deal with the discussed challenges that grid operators are facing.
The article is based on a discussion paper published by IEA ISGAN Annex 6.

The case book Spotlight on Smart and Strong Power T&D Infrastructure spotlights a number of projects sharing best practice in how to meet the challenge to develop the electricity network to become stronger and smarter using different approaches.

For example how:

• Existing and new AC power transmission lines can carry more power by the use of smart technologies such as WAMS and Synchrophasors.
• HVDC lines with Voltage Source Converters can be used for interconnectors that also support the existing grid e.g. by avoiding voltage collapse.
•  The use of smart voltage control concepts can increase the hosting capacity for distributed energy resources

Energy access constitutes one of the fundamental building blocks for economic growth as well as social equity in the modern world. Access to sustainable energy is needed to achieve sustainable development. A microgrid should not be seen as a competitor to the centralized grid but as a complement.

Through examination of several implemented cases from different parts of the world the following topics are considered:

• Analysis of the interaction between centralized grids and microgrids
• Analysis of stakeholder decision parameters for electrification
• Analysis of design differences and requirements for microgrids, depending on the intended purpose and the need of the end customers

It is determined that good planning, suitable requirements and clear regulations for microgrids (in relation to centralized grids) limits the risk of stranded assets and enables better business cases for the involved stakeholders.
The paper is based on the discussion paper The role and interaction of microgrids and centralized grids in developing modern power systems – A case review publiced by ISGAN (International Smart Grid Action Network) Annex 6: Power T&D Systems.

Evolutions in the grid operation sector will require an ever closer cooperation between Transmission System Operators and Distribution System Operators. The current interaction between TSOs and DSOs has been investigated for six specified grid operation challenges, and possible future ways of cooperation have been identified. Technical aspects as well as policy aspects have been taken into account.
The technical requirements for an evolved interaction between TSOs and DSOs can be met using available technology. However, several non-technical issues and points of discussion have been identified, of which some are related to the regulated environment grid operators are working in.

A growing amount of variable renewable energy generation, coupled with increasing consumer involvement through micro generation and flexible demand management, challenge the old ways of planning, operating, and investing in power systems.

In most developed countries, the existing electric infrastructure and workforce is rapidly aging, while in many developing countries, demand for electricity is rapidly rising. Across this landscape of change, it is crucial for policy-makers to understand the synergies between grids and information and communication technologies. Only smart and strong grids will connect people with reliable clean energy. This paper presents a part of the work being done within ISGAN Annex 6 on Power T&D Systems. International Smart Grid Action Network (ISGAN) is an initiative within the Clean Energy Ministerial (CEM) and an Implementing Agreement within the International Energy Agency (IEA). For more information please go to www.iea-isgan.org, or www.cleanenergyministerial.org/Our-Work/Initiatives/Smart-Grid.

This work involves the major economies and consequently major energy users in the world and is addressing the challenges for a secure and clean energy system including the concerns put forward by Intergovernmental Panel on Climate Change (IPCC). IEA publish regularly the reports World Energy Outlook (WEO) and Energy Technology Perspectives (ETP). In addition IEA has published a number of Technology Roadmaps, e.g. on Smart Grids, Wind Energy, Concentrating Solar Power (CSP), Solar PV Energy and Energy Storage. All scenarios showed by IEA are indicating a further increase of electricity as energy carrier both due to the integration of Renewable Energy Sources (RES) and due to increased electricity consumption in many countries, besides common applications also due to increased use of home electronics, heat pumps, air conditioning and electrical transportation (e.g. electrical vehicles, high speed trains). Increased variable electricity production (large scale and distributed) will require mitigation from storage and/or demand response. This will give further demands for capacity, flexibility and reliability of the future power T&D system.

Energy access constitutes one of the fundamental building blocks for economic growth, as well as social equity, in the modern world. Access to sustainable energy is needed to achieve sustainable development. This paper serves as an input document to the global discussion on how to reach the UN goal of “Sustainable Energy for All”, by sharing case study knowledge in the field. The following topics are considered through the examination of several implemented cases from different parts of the world:

• Analysis of the interaction between centralized grids and microgrids.
• Analysis of stakeholder decision parameters for electrification through extension of the central grid or microgrids; such as distance from grid, economic feasibility and environmental sustainability.
• Analysis of design differences and requirements for microgrids, based on intended purpose and the needs of the end customer.

It has been determined that good planning, appropriate requirements and clear regulations for microgrids limit the risk of stranded assets and enable better business cases for the involved stakeholders.

Changing patterns of demand that new types of load such as electric vehicles (EV) will introduce large and unpredictable fluctuations in the power balance as well as variations in voltage can jeopardize the quality and availability of power. The T&D system has to be stronger and smarter to provide the real-time flexibility needed to efficiently handle the new conditions. Investment needs in the power T&D infrastructure are large and require long term planning and deployment. The environmental concerns and public acceptance issues that often arise when constructing additional conventional transmission lines will require more efficient solutions with lower environmental impact.

This Discussion Paper from ISGAN Annex 6 Power Transmission & Distribution Systems Task 3 and 4 focuses on “Smarter & Stronger Power Transmission” and is a review of feasible technologies for enhanced transmission capacity and flexibility in terms of status and deployment. This includes both the primary AC and DC technology for the high voltage transmission grid as well as the information and communication technology (ICT) required to efficiently supervise and operate the power system. Focus is on the development of power electronics including flexible AC transmission (FACTS) and high voltage DC (HVDC), the standardization within ICT such as IEC 61850 and Common Information Model (CIM) in order to obtain vendor independent interoperability as well as the progress of wide area monitoring, protection and control (WAMPAC). The combination of smarter ICT applications together with power electronics such as FACTS and HVDC can be described as a digitalization of the power system operation offering the required flexibility. Most of the examples given are from the Nordic European power system, reflecting the participation of the authors from ISGAN Annex 6 Task 3 and 4, with additional input from North America and selected International case studies.

New technologies are challenging conventional regulatory regimes and new policies and consumer demands are similarly challenging the currently available technologies. For example, as the demand for cleaner energy sources gains ground all over the globe, technological improvements are necessary to integrate large amounts of variable energy sources such as solar and wind into various electricity systems, while ensuring acceptable levels of reliability and security of the system. Similarly, as consumers engage more with electricity systems, demand profiles and consumer choice, among other demand-side elements, are also challenging our system, providing opportunities for demand-side management and related technologies. In this rapidly changing landscape, regulators and policy-makers must consider how consumer participation and new technologies interact with the market place.

This discussion paper from ISGAN Annex 6 Power Transmission & Distribution Systems Tasks 1 and 2 focuses on achieving flexible power delivery by examining the policies and regulations, as well as expansion, planning, and market analysis for the United States and Europe. This review looks at how policies and regulations have changed to accommodate new developments in the operation, planning, and market areas of each grid system. Additionally, it highlights certain efforts undertaken to better understand and implement the policy and regulatory changes in these processes as both the United States and Europe work towards achieving a modernized grid system, specifically including the increased deployment and use of smart grid technologies, e.g., synchrophasor measurement technologies, net metering, distributed generation, energy storage, advanced metering infrastructure.

About ISGAN Discussion Papers: ISGAN discussion papers are meant as input documents to the global discussion about smart grids. Each is a statement by the author(s) regarding a topic of international interest. They reflect works in progress in the development of smart grids in the different regions of the world. Their aim is not to communicate a final outcome or to advise decision-makers, rather to lay the ground work for further research and analysis.