Resilience considerations with increased Distributed Energy Resource (DER) integration

Increasing demand for resilience

Grid resilience is becoming an increasingly important topic of strategic conversation and objective for communities with critical infrastructure and loads. In addition, the reliability of the grid requires to  withstand extreme conditions, notably extreme weather events such as hurricanes, earthquakes and wildfires. Global warming has contributed to a noteworthy increase in the number of destructive weather-related events and customers, commercial practices and industrial processes alike are feeling the impact of not having access to the grid. Additionally, the concept of Climate Resilience is forcing utilities to embed climatic modelling into their strategic thinking to avoid risk and ensure greater resiliency of their networks, with the qualification that climate models still hold many uncertainties.

 

CIGRE’s activities on resilience

The concept of resilience is very broad, and whilst many resilience-related metrics and analytical processes are being researched, there is yet no single universal adoption of these. Resilience definitions are viewed as a multi-faceted concept related to the context of the field, or discipline in which it is applied. While IEEE defines resilience as “the ability to withstand and reduce the magnitude or duration of disruptive events, which includes the capability to anticipate, absorb, adapt to, and / or rapidly recover from such an event.” (IEEE, 2018), resiliency was defined by CIGRE Working Group (WG) C4.47 “Power System Resilience“ as (see [1]): ‘Power system resilience is the ability to limit the extent, severity, and duration of system degradation following an extreme event.

 

Thus, key actionable measures can be deployed before, during and after events to achieve or enhance resilience. The concept of resilience has also been explored by some further Study Committees, and resilience planning for the electrical sector, the utilization of resilience thinking to avert blackouts are examples of work carried out. The recent  work carried out by Work Group D2.50, led to the publication of TB 840, which deals with cybersecurity for power utilities under contingency situations.

 

In line with the work that has been carried out by WG C4.47, the following concepts of resilience will be enhanced by proposed SC C6 Working Groups, by investigating how DER integration may complement such processes:

 

• Anticipation and identification of the threat and associated vulnerabilities
• Response to contain the impact and severity of the threat or incident
• Recovery period in a coordinated manner
• Evolution to a new state of resilience having considered the lessons learnt from the previous event.

 

So far, System Operators/Utilities have not only adopted many of these principles to improve the reliability of their networks, but also to build increased resilience of their networks in response to extreme weather events. Technology is adopted to harden the network, tools and systems are deployed to accelerate the restoration of power to affected areas, and innovative practices are embraced to ensure that customers may survive extended outages with a sense of normality, whilst not having full access to the grid. It is within this context that the use of embedded generation, microgrids and nanogrids are deployed at critical infrastructure and loads. The use of onsite generators, solar PV and battery storage could help communities to recover quicker from such natural disasters. To support these different possibilities to increase resiliency, SC C6 has carried out a significant amount of work related to integrating distributed energy resources (DER), particularly based on renewable energy resources (RES), in distribution grids. The approaches for achieving enhancements, including resilience, to the power grid using local DER are covered in the scope of past and ongoing C6 Working Groups, including battery energy storage systems (WG C6.43), and multi-energy systems (WG C6/C1.33). Resilience can also be  integrated in deploying and exploiting DER flexibility (WG C6/C2.34), DER aggregation (WG C6.35) and DER in microgrids.

 

Given that resilience can in part be achieved by the deployment of DER based on local resources and storage, distributed in large numbers and with built-in redundancy, C6 has examined some key tools to enhance resiliency in the area of power generation. Resilience can be an added objective in DER controller design, whether the DER, including storage, are embedded in microgrids, in virtual power plants (VPP) or aggregated using distributed energy resource management systems (DERMS).

 

Planned SC C6 Working Group activities

C6 proposes to investigate the following themes for the establishment of new Work Group activity in cooperation with other Study Committees when necessary:

 

• Climate change and net zero operation of distribution grids – decarbonization approaches as a guide to improved climate resilience
• Resilience of distribution systems to extreme weather conditions, equipment resilience improvements – vulnerability to transmission system extreme conditions and where DER integration may improve the resilience of these networks
• Forecasting of renewable energy resources (solar) and load, tool for enhancing DER flexibility services, data management and use of AI, use of geospatial location of DER
• Integrating resilience in design of distribution systems for robustness, redundancy and recovery/restoration from blackouts.
• Distribution system planning approaches, taking into account DER flexibility resources, use of AI and optimization tools, thus enhancing the system resilience and reliability.
• Impact of ICT and cybersecurity design considerations in improving resilience, use of the concept of digital twin in resilience planning studies and in operation.

 

Aim and scope of Working Groups

The proposed groups aim to address the technical, economic and regulatory requirements for the adoption of more grid and climate-resilient networks by assessing the best practices, processes, tools, and systems that have been adopted in different parts of the world. Particular emphasis is placed on the adoption and integration of Distributed and Renewable Energy sources, and their related impact on resilience metrics. The Working Groups will investigate trends adopted internationally by incorporating both academic research whilst keeping an eye on emerging industry practices.

 

The intended scope of these WG’s would thus explore:

 

1. Investigate the current practices to analyse and identify resilience metrics, including the data collection approaches and the identification of critical infrastructure and loads.
2. Identify emerging trends and practices to mitigate extreme events
3. Analyse the balance to be achieved by the threat or risk posed versus the appropriate investment in technology to mitigate such risks.
4. Detail the hazards and appropriate response mechanisms to be deployed
5. Identify technical / economic / regulatory challenges associated with increased resilience requirements.
6. Review the methodology and technologies (notably renewable energy integration) used for the analysis and modelling, operation, and planning towards more resilient networks
7. Summarize lessons learned by introducing best practices for resilience management
8. Promote technical papers, webinars, and workshops for the dissemination of best practices for more grid and climate-resilient networks.
9. Coordinate such activities where appropriate with other CIGRE committees, subcommittees, and Working Groups.

 

 The finalisation of the scope and establishment of these new Work Groups is expected in the first half of 2022. Further alignment with working groups that are currently active within C6, notably C6.40 for EV integration, C6.39 for Customer Empowerment and C6.43 for Battery Storage, will provide an added opportunity to embed the resilience principle into a wider set of technology options.

 

[1] https://www.cigre.org/article/GB/news/the_latest_news/defining-power-system-resilience