Power system operation and control

Introduction

Talking about the operation of electrical systems during the year 2020 necessarily implies mentioning the fight against the COVID-19 pandemic by system operators since the first signs at the beginning of the year and intensifying from the month of March. Society has retreated into its homes, industries and commerce have reduced their activities to almost zero, with a direct impact on the demand for electrical systems. However, the system's operation was faced with the challenge of keeping its personnel safe and healthy, especially control room operators and field personnel, maintaining the permanent objective of ensuring security of supply.

These actions showed their effectiveness, even with different characteristics and degrees of intensity, especially in the degree of confinement of operating personnel, in different countries, also affected in different magnitudes in the consequences of the Pandemic ​​for society,. There were no records of direct consequences on the operation of systems around the globe, directly caused by the general health problems of the teams. This is not to say that there were no health consequences for the staff. Cases were verified, but in general, the reports point to situations that are always under control, as a result of people's great effort and many sacrifices to comply with strict protocols.

The hope remains that the first half of 2021, with the application of vaccines and maintenance of individual and collective care, will have brought the beginning of a new phase of better days that will decree the end of the pandemic this year.

It is still within the scope of the Pandemic that we move on to the second prominent theme, which was supplying demand during this unique year of 2020. As of March, there were major reductions in the consumption profile with the retraction of industrial and commercial activity, even if with different intensities in different countries and continents, they marked the need for new operational measures to ensure reliability in the operation, at minimum consumption levels, never seen to be served by a system that has expanded and diversified in technologies and complexity in last years. It was a challenge to accept that the increasingly abundant energy available from renewable sources was entering a phase of necessary restriction due to lack of load and storage structures that could absorb it.

In the second half of the year, not only due to the gradual return and with different profiles of usual human activities, but also due to seasonal characteristics of heating in the southern hemisphere and cooling in the northern hemisphere, the load profile traced a accelerated trajectory to return to previous levels, requiring a return to the known standard of operating actions, even though coexisting with protocols still necessary to maintain the health of the teams.

In this scenario of system operation with changes in resources, in the way to supply demand and in personal habits of the teams, it was up to SC.C2 to share the news and lessons learned from the Pandemic, providing a bridge to the future of the Operation, which, of course, will take forever modifications from this period that we remain in the hope that it is near the end.

But the systems operation did not go through 2020 just dealing with the consequences of the Pandemic. The expansion of RES and its consequences and challenges and the search for lower costs in the production of equipment and techniques that allow energy accumulation as a solution to the variability of these sources continue. Likewise, cost becomes the point of attention for initiatives to produce hydrogen from renewable sources, leaving behind society's enormous carbon production in obtaining energy. These are, of course, aspects that directly interfere in the systems operation routines, and for each such movement there is a need for a solution, either by technology or by protocol of operation, to mitigate its effects on the reliability of electrical systems.

Finally, when digital technology and the new resources available as operation decision tools seem endless and limitless to support operations teams, it is Mother Nature that decides to guarantee the challenge to the results of continuous and reliable supply of demand. Just as examples we can remember the difficulties experienced in extreme weather conditions in both the northern hemisphere, where Texas experienced difficult times in meeting demand due to persistent extremely low temperatures, as in the southern hemisphere, where the lowest rainfall rates of the last 91 years are recorded, even in the wet period, in Brazil, where renewable hydroelectric energy still accounts for more than 65% of the energy matrix.

We really couldn't close this Introduction without commenting the 2020 CIGRE e-session that the Pandemic challenged us to carry out. Much helped by the excellent content of the articles in our Study Committee, we had enormous success in an entirely virtual way, redeeming the possibility of seeing each of the articles being presented by their authors and, in addition, having a small initial discussion, in the form of debates, about its contents. Authors, Chairs, Secretaries and especially Special Reporters were, almost to the maximum, challenged with the task of bringing to each of the participants' homes the whole atmosphere of knowledge sharing and learning that we are used to finding in Paris. And the result couldn't be better - general opinion!!

From nature, from technology or from people behaviour, the challenges seem to have no end. August 2020 to July 2021 was another period that confirmed the need for continuous efforts to overcome the challenges and, in this report, we will present a summary of these activities.

SC C2 Mission and Scope

The scope of the SC C2 covers the technical, human resource and institutional aspects and conditions for a secure and economic system operation of power systems in a way that is in compliance with requirements for network security, against system disintegration, equipment damages and human injuries, and security of electricity supply.

Unbiased and high-quality knowledge dissemination to the power systems community by CIGRE Study Committees is a strong pillar for the development and performance of power systems, especially in the increasingly integrated environment. This applies not only to current but also to future power systems. SC C2 therefore needs to understand, use and integrate results from other Study Committees to assure that technical concepts can be applied in real-time in various contexts and implemented by the System Operators. An area which is unique for C2 is however the dependence on good performance of human resources in performing operational planning and real-time system operation. In these respects, SC C2 embraces a wide range of competence areas and interfaces to other disciplines.

The mission of SC C2 can be summarised in the following four points:

1. To facilitate and promote knowledge dissemination and worldwide collaboration in the field of system operation and control, providing adequate conditions for progress of engineering.
2. To facilitate unbiased technical information exchange, integrating solutions and recommendations for system operations issues and problems. These first two points are achieved among others by the publication of Technical Brochures and papers, delivering tutorials, and participating in conferences, symposia and colloquia.
3. To prepare for the foreseen future challenges by integrating and consolidating available knowledge and taking into account the usage of new and proven technologies. For example, the joint effort of several Study Committees in establishing Joint Working Groups, where different expertise and knowledge is combined, as well as in writing multi-disciplinary Reference Papers.
4. To engage and encourage young members to increase their involvement in the SC activities. By integrating them into Working Groups, a bridge between the young experts and experienced members can be built. SC C2 aims to connect, when possible, a young member to a mentor from the same SC and NC. This gives the opportunity to support the young member's development in a supervised way.

Structure

An overview of the structure of SC C2 is given in Figure 1. The SC has 26 regular members and 14 observer members, 8 active Working Groups of which 2 are joint Working Groups with other CIGRE SCs, and 3 Advisory Groups.

The Strategic Advisory Group, consisting of the SC Chair, Secretary and other SC C2 experts, deals with SC strategy and updates the scope of the Technical Directions. The Publication Advisory Group is responsible for the revision of synopses and papers for CIGRE activities where SC C2 plays a role. The Tutorial Advisory Group (TAG) coordinates the development, planning, quality assurance and delivery of tutorials for conferences, symposia, colloquia and webinars. There are around 175 experts from 35 countries actively involved in SC C2 activities.

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Figure 2 gives an overview of the geographical distribution of SC C2 members.

Main technical directions

SC C2 has defined three Technical Directions (TD) to address important emerging factors that will influence and define new requirements on the System Operation performance.

TD 1: Real-time System Operation and Control

• Wide area control, supervision and increased coordination: integration of regional and national grids into large control areas
• Operation and control of new technologies and system protection schemes
• Increased power system controllability, observability, flexibility and exchange of information, both at transmission and distribution level: e.g. voltage control, frequency control
• Interaction between market mechanisms and power system operation, e.g. ancillary services and congestion management
• Operational real-time security and risk assessment
• Maintaining Security of Supply, Emergency control and restoration procedures and tools
• Information and data exchange in real-time operation

The Working Groups C2.18 and C2/C5.06 address topics in this TD 1.

TD 2: System Operational Planning and Performance Analysis

• Impact on system operation from new generation mix, storage and changes in electrical load behaviour
• Close to real-time operation, crucial for a successful and secure real-time operation, performed both by operational planners and control room operators
• Security assessment in Operational Planning, including coordinated activities
• Assessment of monitoring, control and protection functionalities, including development of new operational strategies
• Emerging Operational Issues for Transmission and Distribution Interaction
• Impact assessment on integration of new technologies
• Blackout integral analysis, defence plans, resilience schemes and restoration strategy considering the evolving environment
• Reliability, network security principles and generation and transmission adequacy
• Operational requirements in Grid Codes
• Information and data exchange in the operational planning timeframes

The Working Groups C2.24, C2.25, C2.26 and C2/C4.41 address topics in this TD 2.

TD 3: Control Centre Infrastructure and Human Resources for System Operation

• Knowledge management and Operator training
• Operator training simulator and other training tools
• Control Centres processes, methods, tools and organisation development
• Tools for decision support and situational awareness
• Integration and exchange of information in system operations and data management
• EMS/SCADA systems, specifications and experiences
• WAMS system requirements and their integration within CC
• Control Centre reliability and resilience
• Information, cyber-security and other vulnerability aspects on control centres

The Working Groups C2.39 and C2.40 address topics in TD 3.

However, it is relevant to point out that some of the WGs touch upon more than one technical direction.

Working Groups Report

Below a short update of the Working Groups active in 2020-2021 is provided.

WG C2.18 - Wide Area Monitoring Protection and Control Systems – Decision Support for System Operators

The Working Group will restart to draft an additional Technical Brochure, which will continue the work already published by WG C2.17 in TB 750 by going one step forward in extending the monitoring to system protection and control. Therefore, after identifying the current experience and control room practice it is planned to describe a flexible and scalable system architecture, identity possibilities for standardisation in event recording and analysis. Further on the process of WAMPAC implementation up to recommendations for control room measures will be addressed. Possibilities for the use of PMUs for special protection schemes (SIPS) and usage for interactions with HVDC links or inverter-based generation will be addressed as well. As the WG members are a good mix between solution vendors, academia, system operators and consultants pragmatic and comprehensive approaches for further developments or already existing solutions are on the way to be documented correspondingly.

WG C2.24 - Mitigating the risk of fire starts and the consequences of fires near overhead lines for system operations

The WG C2.24 is made up of utility representatives, consultants and academics, from 10 countries. The first draft of the Technical Brochure of the work of WG C2.24 has been prepared. It includes the results of the survey of a total of 27 transmission and/or distribution utilities on wildfire (bushfire) risk management practices. The scope of the study now includes a Prevent, Prepare, Respond and Recover framework of best practice, which aims to assist utilities with strategies to manage the risk of fire starts from powerline assets.  The next draft of the TB is expected by Q4-2021.

WG C2.25 - Operating strategies and preparedness for system operational resilience

The Working Group was approved in June 2018. The WG finalized its TB “Operating strategies and preparedness for system operational resilience” early 2021. The TB was officially published end of April 2021 on e-cigre here. During the work of the WG, in 2019, WG C2.25 performed a survey collecting information in relation to system operational resilience. 38 responses were received and analysed. The information will be included in the further work and provide relevant information for the TB. A short follow-up questionnaire was issued in summer 2020. A CSE paper providing first glance on the WG findings was published in June 2020. To officially close all activities of the WG a tutorial will be organized during the CIGRE 2021 Centennial Session.

WG C2.26 - Power system restoration accounting for a rapidly changing power system and generation mix

This Working Group, approved in March 2019, aims to identify and manage emerging risks on system restoration, investigate opportunities for increased utilisation of new and emerging technologies during system restoration, and enable system operators and network owners to continue to execute a successful system restart when required despite the rapidly changing generation mix. The work carried out so far in this WG includes discussion on system restoration practices and challenges in more than 10 countries from those represented in the WG, the role of inverter-based resources in system restoration either as a black starter or to support system restoration, tools and techniques for analysing system restoration including real-time and offline electromagnetic transient simulation and fast decision support tools, and physical testing demonstrating the capability of VSC HVDC during restoration. Emerging areas recently started include system restoration subject to cyber-security, loss of control centres, and pandemic situations. Other immediate areas of work include power system modelling and physical testing to better understand the roles and limitations of various types of inverter-based resources during system restoration. The TB is planned to be published in Q4 2021, however, a delay of up to a maximum of six month may occur due to the impact of COVID-19.

WG C2.39 - Operator Training in Electricity Grids at Different Control Levels and for Different Participants/Actors in the New Environment

The Working Group started its work in August 2018. By the end of 2019, the final version of Document Nº 1 was completed and clarified the existing situation on the subject based on the scenarios presented by the 16 companies surveyed. From there, the group started to work on the 9 items considered important for greater detailing of updated training based on simulator exercises. It is worth mentioning the great difficulty in developing the work throughout 2020, with the need to realign the way all members work due to the consequences of the COVID-19 Pandemic, generating the need to readjust the work schedule, with inevitable and significant delay. Warm-up texts and new specific questionnaires were prepared for each of these 9 topics. Questionnaires were applied and 10 to 14 responses were obtained for the new questionnaires. The Group is currently working on analyzing the responses received and preparing concluding documents for each of the topics. With Document Nº 1, each one of these topics will be a chapter of the Technical Brochure, the main deliverable of the Working Group. This TB is expected in Q1-2022.

WG C2.40 - TSO-DSO Co-Operation – Control Centre Tools Requirements

The paradigm shift in the configuration of the power system with a high penetration of distributed renewable generation connected at the DSO level creates a new dimension in TSO-DSO coordination practices and procedures. The role of this WG, approved in June 2018, is to specify a set of control centre tools and related IT platforms for both the TSO and DSO to manage and operate this newly evolved power system. A critical aspect that must be addressed is that the tools must enable a high level of cooperation between the TSO and DSO. Interoperability between the tools should be developed considering different time-horizons (at least real-time and short-term operational planning) and different services. The Working Group published a paper at the Paris 2020 session (C2-205 TSO-DSO Cooperation: Control Centre Tool Requirements). The Working Group has 25 experts from 12 different countries and expects to publish its TB in Q3-2021.

JWG C2/B4.38 - Capabilities and requirements definition for Power Electronics based technology for secure and efficient system operation and control

The JWG continued to work on the development of an overview of examples and best practices and also addressed how system operations can prepare for the expected large amount of power electronics interfaced devices. Again, the synergy between the operations experts and the power electronics technology experts proved to be really beneficial for performing this tasks. The JWG published the Technical Brochure with reference number 821 in November 2020 and finalised its work shortly after.

JWG C2/C4.41 - Impact of high penetration of inverter-based generation on system inertia of networks

The rapid increase in integration of renewable generation globally has led to concerns around the depletion of power system inertia more especially when large fleets of static renewable generation displace the conventional synchronous generation. The objective of this JWG is to study the impact of depleting power system inertia and to advice and formulate philosophies for system operations in order to prepare for the ongoing energy transition. This JWG has produced two papers to date and has conducted a survey about industry experience on FCR, FFR requirements and minimum inertia levels. The JWG comprises 20 experts from 17 countries. The JWG is wrapping up its work and held a successful webinar in December 2020. The draft TB was issued in mid-April 2021 and the team received comments beginning of June 2021. The team is currently addressing all comments to finalise the TB. The team’s deadline for addressing the comments is 14th July 2021. The final TB will be published by end of July 2021.

JWG C2/C5.06 - The Impact of Electricity Market Interventions by System Operators during Emergency Situations

For this new JWG the terms of reference were approved in April 2021, after that the call for nominations was launched. After the selection of members from the nominees is done it is expected that the work can start in Q3 2021. The objective of the JWG is to find out what the impact of market interventions is among others by collecting experiences from actual situations. Even the question to what extend this questions contributed to safeguarding the system during emergency situation will be addressed. The planning for the JWG is to deliver the TB by mid-2023.

Past Tutorials & Webinars

During the Paris Session, a tutorial was delivered on behalf of SC C2 on 1 September 2020. During the tutorial the main results of the work conducted under joint Working Group C2/B4.38 "Capabilities and requirements definition for Power Electronics based technology for secure and efficient system operation and control" were presented. Furthermore, on 29 October 2020, this JWG organized a webinar in which the main contents of the Technical Brochure (TB) 821 were presented.

On 10 December 2020, Mpeli Rampokanyo, Convener of JWG C2/C4.41, together with several JWG members, presented a CIGRE Academy Webinar titled “Impact of high penetration of inverter-based generation on system inertia of networks”.

Joint Technical Activities

The SC also participates in other Working Groups that are being led by other SCs. SC C2 is part of Joint Working Groups C6/C2.34 and D2/C2.48, C4/C2.58/IEEE and C4/C2.62/IEEE. The SC has active liaisons in the Working Groups A1.65, C1/C4.36, C6.36 and C6.40.

Publications

The following publications have been made since August 2019 as a result of work carried out by SC C2 Working Groups:

• WG C2.26 published a CSE journal paper “System Strength Challenges and Solutions Developed for a Remote Area of Australian Power System with High Penetration of Inverter-Based Resources” in CIGRE Science & Engineering Journal, volume 20 (February 2021).
• JWG C2/B4.38 published a CSE journal paper “Capabilities of Power Electronic Devices in Enabling the Energy Transition and Mitigating System Operational Challenges” in CIGRE Science & Engineering Journal, volume 20 (February 2021).

WG C2.40 and JWG C2/C4.41 are finalising their Technical Brochures, to be published in Q3-2021. WG C2.24 is also finalising its Technical Brochure for publication in Q4-2021.

Awards

The following SC C2 members received CIGRE awards in 2021:

• Vinay Sewdien (Netherlands) was awarded the Centennial TC Award;
• Susana de Graaf (Netherlands), Marija Zima (Switzerland), Anjan Bose (USA) and Renuka Chattergee (USA) were awarded the Pioneer e-session Achievement Award.

Workshops, Conferences and Seminars

From August 2020 onwards, the following SC C2 members took part in events:

• Walter Sattinger, convener of WG C2.18, delivered a keynote speech on data analytics with real time monitoring systems for CIGRE Colombia on 13 March 2020. The presentation was titled “Data Analytics with a Real Time Monitoring System – WAM System & SCADA System”.
• Walter Sattinger, convener of WG C2.18, delivered a keynote speech titled “Wide Area Monitoring, Protection and Control Systems – Support for Control Room Applications” in the International Tutorial on Wide Area Measurement Systems and their use in improving Power System resiliency. The online tutorial was organized by Power System Operation Corporation Limited (POSOCO), India, under the aegis of CIGRE NSC C2 on System Operations and Control on 22 January 2021.
• Jan van Putten, convener of JWG C2/B4.38, delivered a keynote speech for CIGRE / VDE Young EnergyNet titled “How Power Electronics can help to mitigate the Challenges of Energy Transition” focusing on part of the work developed by the JWG.

Future Activities

The next events for SC C2 are:

• 2021 CIGRE Virtual Centennial Session: The Large Disturbances Workshop, organised jointly with SC C5, will take place on Monday 23 August 2021. The following presentations are confirmed for the workshop:

• Jens Jacobs and members of WG C2.25 will give a tutorial, titled “Operating Strategies and Preparedness for System Operational Resilience”, planned for 25 August 2021 during the CIGRE Virtual Centennial Session.
• 2022 KYOTO Symposium – 3-8 April, 2022 - Chair: SC C6 and D2 - B3, C1, C2, C4, C5

Conclusions

Just as we are getting used to the fact that the technologies of generation, transmission and control of electrical systems have undergone disruptive evolutions in recent years, it is our understanding that the task of sharing and learning knowledge must always evolve as well. Some reasons for this inevitably arise, as happened in the case of the pandemic, and force us to find emergency solutions that guarantee our good results. Other reasons are continuously present and in our activities we have always included a focus on the most important drivers currently in terms of technology and the training of operating teams.

Due to the central position of operation and control, in its end-to-end concept, in the results of electrical systems, SC C2 has been seeking actions that allow interactions with other Study Committees, creating and sharing knowledge that can be used in various fields of action. We remain aware of this responsibility and confident in the ability of our participants to collaborate, maintaining the basic spirit that drives and differentiates CIGRE's activities.

Contact

• Contact of the Chair and/or the Secretary of the Study Committee