elering-15
Predict flexibility availability
1. Description of the Use Case
1.1. Name of the Use Case
| ID | Area /Domain(s)/Zone(s) | Name of the Use Case |
|---|---|---|
| 1 | Market for flexibilities, | elering-15 |
1.2. Version Management
| Version No. | Date | Name of author(s) | Changes | Approval status |
|---|---|---|---|---|
| 1 | 2018-05-08T00:00:00 | |||
| 2 | 2018-05-08T00:00:00 | Mitchell Curtis (Upside), Graham Oakes (Upside), | First Draft | |
| 3 | 2018-07-04T00:00:00 | Ricardo Jover (EDF), Eric Suignard (EDF), | ||
| 4 | 2018-07-10T00:00:00 | Ricardo Jover (EDF), Eric Suignard (EDF), | Changes from Mitchell Curtis | |
| 5 | 2018-08-02T00:00:00 | Eric Suignard (EDF), | ||
| 6 | 2018-09-21T00:00:00 | Eric Suignard (EDF), | Remarks from Innogy. | |
| 7 | 2018-10-04T00:00:00 | Eric Suignard (EDF), | Version post WP5&9 physical meeting in Tallinn | |
| 8 | 2018-10-17T00:00:00 | Eric Suignard (EDF), | Version reviewed by WP5&9 partners | |
| 9 | 2019-05-07T00:00:00 | Eric Suignard (EDF), | WP6-7-8 demos alignment and miscellaneous changes | |
| 10 | 2019-06-05T00:00:00 | Ricardo Jover (EDF), Eric Suignard (EDF), | Changes following WP5&9 workshop in Chatou | |
| 11 | 2020-06-16T00:00:00 | Eric Suignard (EDF), | innogy’s and Elering’s review |
1.3. Scope and Objectives of Use Case
| Scope | The scope of this use case is the prediction of flexibility product availability. |
| Objective(s) | The objective of this use case is to detail how the prediction of flexibility product availability is undertaken. |
| Related business case(s) |
1.4. Narrative of Use Case
Short description
This use case describes how the prediction of flexibility availability is undertaken. Flexibility products are described as either slow (e.g. Manual Frequency Restoration Reserve (mFRR) and the UK Short Term Operating Reserve (STOR)) or semi-fast (e.g. Automatic Frequency Restoration Reserve (aFRR)) or fast (e.g. Frequency Containment Reserves (FCR) and Fast Frequency Response (FFR)) and can provide services for balancing and congestion management at local and national levels for TSOs and DSOs.
The assessment of flexibility availability in this use case is split into three timeframes:
- Investment planning (3+ years ahead) aims to understand future availability and if the predictions highlight insufficient capacity that needs addressing.
- Operation planning (days to years ahead) aims to predict the short, medium and long term availability of flexible products that have committed to provide service.
- Real time Planning (Intraday operation) aims to predict the current availability of flexible products for balancing and congestion management requirements for that day. This time frame is covered by DER-SCADA, flexibility bidding and flexibility activation SUCs. It relates to understand the real time flexibility availability which could be based on forecasting using historical data on how assets have performed. For example, the flexibility bidding SUC could say that today 10MW had been awarded for usage, the flexibility activation SUC could identify that, when called on, only 9MW responded. This information would be fed into the prediction forecaster, so that in the future it could tell the flexibility bidding SUC that, if it wants 10MW, then it should get 11MW as it is predicted that 10% will not respond.
Complete description
1.5. Key Performance Indicatiors (KPI)
| ID | Name | Description | Reference to mentioned use case objectives |
|---|
1.6. Use case conditions
| Assumptions |
|---|
| Operational Planning timeframe requires data on the amount and type of flexibility that has been acquired |
| Prerequisites |
|---|
| Flexibility products have been predefined and are being used |
1.7. Further information to the use case for classification/mapping
| Relation to other use cases |
|---|
| Level of depth |
| Prioritisation |
| Generic, regional or national relation |
| Nature of the use cases |
| SUC |
| Further keywords for classification |
1.8. General remarks
| General remarks |
|---|
2. Diagrams of Use Case
3. Technical Details
3.1. Actors
| Actor Name | Actor Type | Actor Description | Further information specific to this Use Case |
|---|---|---|---|
| Data Exchange Platform | System | Data exchange platform (DEP) is a communication platform the basic functionality of which is to secure data transfer (routing) from data providers (e.g. data hubs, flexibility service providers, TSOs, DSOs) to the data users (e.g. TSOs, DSOs, consumers, suppliers, energy service providers). DEP stores data related to its services (e.g. cryptographic hash of the data requested). The DEP does not store core energy data (e.g. meter data, grid data, market data) while these data can be stored by data hubs. Several DEPs may exist in different countries and inside one country. | |
| Distribution System Operator (DS_O) | Business | Elaborate network development plan (including defining system needs for distribution) Ensure a transparent and non-discriminatory access to the distribution network for each user Operate the distribution grid over a specific region in a secure, reliable and efficient way Optimize system operation distribution grid from planning to real-time, using available levers (grid expansion, flexibility activation,…) Assess network status of the distribution grid and broadcast selected information of the network status to eligible actors (e.g. aggregators, other system operators) Support the Transmission System Operator in carrying out its responsibilities (including load shedding) and coordinate measures if necessary | |
| Transmission System Operator (TS_O) | Business | Elaborate network development plan (including defining system needs for transmission) Ensure a transparent and non-discriminatory access to the transmission network for each user Operate the transmission grid over a specific region in a secure, reliable and efficient way Secure and manage in real time the physical generation-consumption balance on a geographical perimeter, including ensuring the frequency control service Optimize transmission system operation from planning to real-time, using available levers (grid expansion, flexibility activation,…) Assess network status of the transmission grid and broadcast selected information of the network status to eligible actors (e.g. aggregators, other system operators) Provide data to the interconnection capacity market operator for the management of cross border transactions In critical situations, implement dedicated actions and deliver alerts during stress events If necessary, implement emergency measures (e.g. system defence plan) including load shedding | |
| System Operator | Business | System Operator means a natural or legal person responsible for operating, ensuring the maintenance of and, if necessary, developing the system in a given area and, where applicable, its interconnections with other systems, and for ensuring the long-term ability of the system to meet reasonable demands for the distribution or transmission of electricity (cf. ENTSOE-EFET-ebIX harmonized role model 2019). Can be:
NB: In some countries (e.g. Germany and Poland), the high voltage network is part of the distribution grid and in other countries (e. g. France and Italy) the high voltage network is part of the transmission grid. A System Operator can be:
| |
| Flexibility Platform | System | Flexibility Platform (FP) for System Operators and Flexibility Service Providers that enables the trading of different flexibility products and services. A FP is operated by a Market Operator. Available to System Operators and Flexibility Services Providers. It is used to support the prequalification, the bidding, the activation and the verification processes, ensuring coordination between activities undertaken by several operators using the same flexible resources. Several national and regional FPs may exist. | |
| Flexibility Service Provider | Business | Can be a Distribution Network Flexibility Provider or a Transmission Network Flexibility Provider (cf. definitions in T3.3 deliverable). Similar to Flexibility Aggregator. Can be both aggregator and individual consumer/generator. Type of Energy Service Provider. | |
| DEP Operator | Business | Data exchange platform operator owns and operates a communication system which basic functionality is data transfer. |
3.2. References
| No. | References Type | Reference | Status | Impact on Use Case | Organistaor / Organisation | Link |
|---|
4. Step by Step Analysis of Use Case
4.1. Overview of Scenarios
| No. | Scenario Name | Scenario Description | Primary Actor | Triggering Event | Pre-Condition | Post-Condition |
|---|---|---|---|---|---|---|
| 1 | TSO Predicting Flexibility Availability for Investment Planning | |||||
| 2 | DSO Predicting Flexibility Availability for Investment Planning | |||||
| 3 | System Operator Predicting Flexibility Availability for Operational Planning | The System Operator can be a TSO or a DSO. | ||||
| 4 | System Operator Predicting Flexibility Availability for Real Time Planning | The System Operator can be a TSO (imbalance) or a DSO (congestions). |
Notes
4.2. Steps – Scenarios
| Scenario Name: |
|---|
| TSO Predicting Flexibility Availability for Investment Planning |
| Step No. | Event. | Name of Process/ Activity | Description of Process/ Activity. | Service | Information Producer (Actor) | Information Receiver (Actor) | Information Exchanged | Requirements, R-ID |
|---|---|---|---|---|---|---|---|---|
| 1.1 | Assess the levels of expected generation and intermittent electricity supply | Assessment on transmission network. Example for intermittent electricity supply: renewables. | e1faae3f-9109-40ca-9468-129b57e584e9 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 | ||||
| 1.2 | Assess the levels of expected inflexible and flexible electricity demand | Assessment on transmission network. Example for inflexible electricity demand: lights. Example for flexible electricity demand: electric vehicle charging. | e1faae3f-9109-40ca-9468-129b57e584e9 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 | ||||
| 1.3 | Compare supply and demand assessments across the country and for individual areas | There should be sufficient capacity and flexibility, in order to maintain agreed KPI’s (e.g. having a 10% reserve margin) | e1faae3f-9109-40ca-9468-129b57e584e9 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 | ||||
| 1.4 | Signal to the market with appropriate mechanisms the national and local requirements | Examples of a national signal: flexibility market, demanding futures on flexibility Modsarus Use Case::InstanceName=National and local requirements Modsarus Use Case::InstanceDescription= | e1faae3f-9109-40ca-9468-129b57e584e9 | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 | ||
| 1.5 | Forward the national and local requirements | Modsarus Use Case::InstanceName=National and local requirements Modsarus Use Case::InstanceDescription= | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | 908bfa7a-c616-4b2b-a712-04aac115429b | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 | ||
| 1.6 | Register flexibility needs | National and local requirements to register: - Amount of firm electricity supply required - Amount of intermittent electricity supply required - Amount of fast (seconds response rate) flexibility product required - Amount of slow (minutes response rate) flexibility product required | 908bfa7a-c616-4b2b-a712-04aac115429b | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 a8e209b8-668f-4618-94f6-45cfec8e4577 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 |
| Scenario Name: |
|---|
| DSO Predicting Flexibility Availability for Investment Planning |
| Step No. | Event. | Name of Process/ Activity | Description of Process/ Activity. | Service | Information Producer (Actor) | Information Receiver (Actor) | Information Exchanged | Requirements, R-ID |
|---|---|---|---|---|---|---|---|---|
| 2.1 | Assess the levels of expected generation connected to the distribution grid, inflexible and flexible electricity demand across all areas of its distribution network | Assessment on distribution network. Example for inflexible electricity demand: lights. Example for flexible electricity demand: electric vehicle charging. Examples of areas of distribution network: street, town, region. | b8c224b3-3a8c-44b9-8eb8-8d38f96be10f | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 | ||||
| 2.2 | Assess the levels of expected distributed generation across all areas of its distribution network | Assessment on distribution network. Example for expected distributed generation: solar. Examples of areas of distribution network: street, town, region. | b8c224b3-3a8c-44b9-8eb8-8d38f96be10f | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 | ||||
| 2.3 | Use the demand and distributed generation assessment to understand which areas could utilise flexible electricity demand to reduce the need for network reinforcement | Example for flexible electricity demand: electric vehicle charging | b8c224b3-3a8c-44b9-8eb8-8d38f96be10f | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 | ||||
| 2.4 | Signal to the market with appropriate mechanisms the requirements | Example for signal: DSO flexibility calls for tenders Modsarus Use Case::InstanceName=Local requirements Modsarus Use Case::InstanceDescription= | b8c224b3-3a8c-44b9-8eb8-8d38f96be10f | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 | ||
| 2.5 | Forward local requirements | Modsarus Use Case::InstanceName=Local requirements Modsarus Use Case::InstanceDescription= | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | 908bfa7a-c616-4b2b-a712-04aac115429b | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 | ||
| 2.6 | Register flexibility needs | Requirements to register for network reinforcement: - Amount of reinforcement required that cannot be addressed with flexibility - Amount of fast (seconds response rate) flexibility product required - Amount of slow (minutes response rate) flexibility product required | 908bfa7a-c616-4b2b-a712-04aac115429b | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 a8e209b8-668f-4618-94f6-45cfec8e4577 |
| Scenario Name: |
|---|
| System Operator Predicting Flexibility Availability for Operational Planning |
| Step No. | Event. | Name of Process/ Activity | Description of Process/ Activity. | Service | Information Producer (Actor) | Information Receiver (Actor) | Information Exchanged | Requirements, R-ID |
|---|---|---|---|---|---|---|---|---|
| 3.1 | Publish the results of prequalification with additional restrictions information | Modsarus Use Case::InstanceName=Prequalification results Modsarus Use Case::InstanceDescription= | 908bfa7a-c616-4b2b-a712-04aac115429b | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | ||
| 3.2 | Forward prequalification results | Modsarus Use Case::InstanceName=Prequalification results Modsarus Use Case::InstanceDescription= | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | 63eb2d86-aa08-444e-88dc-51f7f64e714e 63eb2d86-aa08-444e-88dc-51f7f64e714e 63eb2d86-aa08-444e-88dc-51f7f64e714e | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | ||
| 3.3 | Register flexibility needs | 908bfa7a-c616-4b2b-a712-04aac115429b | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | |||||
| 3.4 | Predict fast and slow flexibility product availability for the short-term period | Based on the flexibility energy that has been awarded to providers. The flexibility energy is adjusted using forecasting models of actual delivery by the providers and historical data Modsarus Use Case::InstanceName=Flexibility Need Modsarus Use Case::InstanceDescription= | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | ||
| 3.5 | Predict fast and slow flexibility product availability for the medium-term period | Based on the flexibility capacity that has been awarded. Modsarus Use Case::InstanceName=Flexibility Need Modsarus Use Case::InstanceDescription= | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | ||
| 3.6 | Predict fast and slow flexibility product availability for the long-term period | Based on the flexibility capacity that has been already awarded and still to be awarded based on their acquisition mechanisms (e.g. capacity market) Modsarus Use Case::InstanceName=Flexibility Need Modsarus Use Case::InstanceDescription= | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 | ||
| 3.7 | Forward flexibility needs | Modsarus Use Case::InstanceName=Flexibility Need Modsarus Use Case::InstanceDescription= | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | 908bfa7a-c616-4b2b-a712-04aac115429b | a60e2b25-b378-4f14-9755-26f4a9b5ea69 | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 9553a4c6-df9f-4224-a64e-335c14565f42 |
| Scenario Name: |
|---|
| System Operator Predicting Flexibility Availability for Real Time Planning |
| Step No. | Event. | Name of Process/ Activity | Description of Process/ Activity. | Service | Information Producer (Actor) | Information Receiver (Actor) | Information Exchanged | Requirements, R-ID |
|---|---|---|---|---|---|---|---|---|
| 4.1 | Send large FSPs real time signals about their current and near-term ability to provide flexibility | For large producers (FSPs): some data are already exchanged in real time between large producer’s SCADA and network operator’s SCADA. Modsarus Use Case::InstanceName=Flexibility Potential Modsarus Use Case::InstanceDescription= | 2b8f28a5-4b5a-49fb-92fa-1728b089ce00 | 63eb2d86-aa08-444e-88dc-51f7f64e714e | ec556f1b-8608-4de1-ab7c-a7e614f2bc37 | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 | ||
| 4.2 | Send small FSPs real time signals about their current and near-term ability to provide flexibility | For FSPs who do not have a SCADA to exchange data directly with Network Operators. We will consider that data exchanges between small FSPs and system/network operators will be done in real time via Data Exchange Platforms. Modsarus Use Case::InstanceName=Flexibility Potential Modsarus Use Case::InstanceDescription= | 2b8f28a5-4b5a-49fb-92fa-1728b089ce00 | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | ec556f1b-8608-4de1-ab7c-a7e614f2bc37 | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 | ||
| 4.3 | Forward small FSPs real time signals | Modsarus Use Case::InstanceName=Flexibility Potential Modsarus Use Case::InstanceDescription= | 4e694b8b-e0eb-4b2a-ae7a-1bcb6f656385 | 63eb2d86-aa08-444e-88dc-51f7f64e714e | ec556f1b-8608-4de1-ab7c-a7e614f2bc37 | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 | ||
| 4.4 | Receive the flexibility predictions | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 | |||||
| 4.5 | For small FSPs that cannot provide real time signals, predict their current and near-term ability to provide flexibility availability | For FSPs that cannot offer real time signals. Flexibility availability is based on historical information and prediction parameters (e.g. weather). | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 | ||||
| 4.6 | Combine the flexibility predictions | Done to understand availability over the day for both slow and fast flexibility products. | 63eb2d86-aa08-444e-88dc-51f7f64e714e | 9553a4c6-df9f-4224-a64e-335c14565f42 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 405bf996-c666-4b6e-ae81-be6dc03e3eb5 11c3359a-b4bb-40d3-a055-6296bf5860a7 |
5. Information Exchanged
| Information exchanged ID | Name of Information | Description of Information Exchanged | Requirement |
|---|---|---|---|
| a60e2b25-b378-4f14-9755-26f4a9b5ea69 | Flexibility Need | —- | |
| ec556f1b-8608-4de1-ab7c-a7e614f2bc37 | Flexibility Potential | —- |
6. Requirements (optional)
| Category Identifier | Name | Description | mRID |
|---|---|---|---|
| Cat1 | Task 5.3 | Requirements integrated from Task 5.3. | 1880e39c-7084-4785-8c02-297057abe312 |
| Identifier | Name | Description | mRID |
|---|---|---|---|
| Req1 | FPRED-REQ1 | Collection of data for prediction (long term - years) | 8fd0604e-3f8d-497b-8b6c-65e519cc1175 |
| Req2 | FPRED-REQ2 | Computation of predictions (long term - years) | a8e209b8-668f-4618-94f6-45cfec8e4577 |
| Req3 | FPRED-REQ6 | Computation of predictions (long term - intraday operation) | 9f08745f-29a2-4fad-86ae-8a7b6f9a3ab8 |
| Req4 | FPRED-REQ3 | Collection of data for prediction (medium-term - days to years ahead) | 405bf996-c666-4b6e-ae81-be6dc03e3eb5 |
| Req5 | FPRED-REQ4 | Computation of predictions ( medium-term - days to years ahead ) | 9553a4c6-df9f-4224-a64e-335c14565f42 |
| Req6 | FPRED-REQ5 | Collection of data for prediction (short term - intraday operation) | 11c3359a-b4bb-40d3-a055-6296bf5860a7 |
7. Common Terms and Definitions
8. Custom Information (optional)
| Key | Value | Refers to Section |
|---|