UC-GR-2

PMU data integration into SE tool

1. Description of the Use Case

1.1. Name of the Use Case

Use case identification

IDArea /Domain(s)/Zone(s)Name of the Use Case
UC-GR-2Area: Energy system
Domains: Distribution, DER, Customer Premises
Zones: Station, Operation
PMU data integration into SE tool

Notes:

  • ID - uniqe identification label: DE-1/GR-3/IT-2
  • Area /Domain(s)/Zone(s) - placement of the use case in the SGAM domains and zones. It can be left blank if you are not sure.

1.2. Version Management

Version management

Version No.DateName of author(s)ChangesApproval status
0.117th June 2020Themistoklis Xygkis, Panagiotis Pediaditis, Stavroula Tzioka, Eleni Daridou, Dimitris StratogiannisInitial creationDraft

1.3. Scope and Objectives of Use Case

Scope and objectives of use case

ScopeThe scope of the UC is the integration of measurement data obtained from PMUs into the State Estimation tool.
Objective(s)* To reinforce network observability and controllability via improved state estimation performance.
* To ensure smooth incorporation of synchronised measurement data derived from PMUs into the preexisting system of conventional measurements.
Related business case(s)add text

Notes:

  • Scope - describes the aims and boundaries of the use case in a short, precise text.
  • Objective(s) - goals of the use case, in form of bullet points and a short headline.
  • Realted business case(s) - optional

1.4. Narrative of Use Case

Short description Measurement data obtained from the installed PMUs are integraded in the State Estimation tool and used to enhance the network observability. The installation of PMUs at selected buses is sure to upgrade the overall metering infrastructure of the network, since they record synchronized measurements of bus voltage phasors as well as a number of line current phasors—all of which are independent of each other and count as individual measurements. Yet, their proper utilization via the SE tool is a challenging task due to a) the intense discrepancies in update rates between conventional and PMU measurements, b) the provision of current measurements which often lead to various numerical problems, and c) the contrast between the large weighting factors linked to PMU measurements compared to the much lower ones linked to pseudo-measurements, which usually raises ill-conditioning issues. The goal is to ensure that the integration of PMU data will be smooth and all the aforesaid problems will be circumvented.

Complete description A measurement set, composed of actual and historical measurement data obtained from the dispersed metering devices (AMR, GIS, SCADA, PMUs) installed throughout the network, is available to the DSO for real-time operation purposes. The aforementioned data refer to a) synchronised measurements of bus voltage phasors and line current phasors (magnitude and angle) and b) conventional measurements of power flows and voltage magnitudes at the top of distribution feeders, power injections from distributed generation units, and load pseudo-measurements for aggregated consumer demand at MV/LV transformer level. Given that the network model (topology) is known with a good degree of certainty, the state estimation tool ensures that the network is observable based on the available measurement set, reconciles the PMU data with the conventional measurements, and, subsequently, calculates the estimated state vector, that is, the voltage magnitudes and angles of all network buses. Given the successful integration and use of the PMU data in the SE tool, the overall performance of the SE tool will be enhanced; the network state will be calculated with increased precision compared to conventional-measurements-only scenarios (uc-GR-1), and high quality real-time operational standards for distribution management applications will be met.

1.5. Key Performance Indicatiors (KPI)

IDNameDescriptionReference to mentioned use case objectives
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Notes: Can be left blank now

1.6. Use case conditions

AssumptionsPrerequisites
*The network model (topology) is known with a good degree of certainty
*DSO systems (e.g.AMR, GIS, SCADA) being operational
*PMUs are installed and PMU data is available for SE tool

Notes:

  • Assumptions - general presumptions about conditions or system configurations (e.g. customer’s consent required for some steps; simulation of TSO)
  • Prerequisites - specify which requirements have to be met so that the basis scenario use case can be successfully accomplished.

1.7. Further information to the use case for classification/mapping

OPTIONAL - you can leave it blank

Relation to other use cases
Associate with UC-GR-5
Level of depth
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Prioritisation
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Generic, regional or national relation
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Nature of the use cases
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Further keywords for classification
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Notes:

  • Relation to other use cases - relation to other use cases in the same project or thematic area. Possible relation types are for instance include, extend, invoke, or associate.
  • Level of depth - reflects the degree of specialisation of the use case. Although no common notation is settled, descriptions like high level use case, generic, detailed, or specialised use case are often used.
  • Prioritisation - helps to rate the use cases in a project from very important to nice-to-have with labels like obligatory/mandatory or optional which have to be agreed upon beforehand.
  • Generic, regional or national relation - for the purpose of generalisation if use case is applied to areas where restictions by law or silimiar issues occur.
  • Nature of the use cases - describes the viewpoint and field of attention like technical, political, business/market, test, etc.

1.8. General remarks

General remarks
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Notes: Add any remarks which do not fit in any other category

2. Diagrams of Use Case

Diagram of Use Case

Sequence Diagram of Use Case

3. Technical Details

3.1. Actors

Actor NameActor TypeActor DescriptionFurther information specific to this Use Case
AMRSystemAutomatic Meter Reading system
DMSSystemDistribution Management System
DSOPersonDistribution System Operator, the entity responsible for the safe and secure operation and management of the distribution system; for data management associated with the use of the distribution system; for procurement of flexibility services using optimization algorithms and the DSO Technical Platform.
DSO Data ServerSystemDatabase containing data from AMR, DMS & SCADA
DSOTPSystemDSO Technical Platform
GISSystemGeographical Information System
PMUDevicePhasor Measurement Unit
SCADADeviceSupervisory Control And Data Acquisition system

Notes:

  • Actor Type - Device/ Sytem/ Person

3.2. References

OPTIONAL - you can leave it blank

No.References TypeReferenceStatusImpact on Use CaseOrganistaor / OrganisationLink
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4. Step by Step Analysis of Use Case

4.1. Overview of Scenarios

No.Scenario NamePrimary ActorTriggering EventPre-ConditionPost-Condition
1PMU data integrationSCADA,PMUState estimation accuracy to be improvedPMU field intstallationHigh-accuracy state vector

Notes This part describes the possible scenarios of the use case. The scenarios should comply with the sequence diagrams in Sect. 2 of the template, so that every step describes one part of a communication or action. Apart from a normal success scenario, different failure scenarios or alternatives can be included to describe situations where preconditions are not satisfied or unwanted states are attained.

  • Primary Actor - the first actor appearing in the scenario at the incident causing the scenario to begin.
  • Triggering Event - the incident causing the scenario to begin.
  • Pre-Condition - indicates which terms have to be fulfilled for the scenario to be executed.
  • Post-Condition - indicates which terms should be valid after the scenario. TIt can also specify whether a scenario has been successfully completed or not.

4.2. Steps – Scenarios

Scenario Name: No. 1 - PMU data integration

Step No.Event.Name of Process/ ActivityDescription of Process/ Activity.ServiceInformation Producer (Actor)Information Receiver (Actor)Information ExchangedRequirements, R-ID
1Measurements from the Distribution NetworkData AquisitionVarious field measurements that reflect the network state are communicatedREPORTSCADA,DMS,GIS,AMR, PMUsDSO Data ServerI-01
2Measurements from the Distribution NetworkData AquisitionVarious field measurements that reflect the network state are communicatedREPORTDSO Data ServerBAPI-01
3Measurements from the Distribution NetworkData VerificationAll data received gets verified and secured via blockchain technologyEXECUTEBAPBAP
4Measurements from the Distribution NetworkData AcquisitionVerified and secured data is delivered to the DSOTPREPORTBAPDSOTPI-03
5Measurements from the Distribution NetworkPMU Data AquisitionPMU measurements that reflect the network state are communicatedREPORTPMUDSOTPI-04
6Measurements from the Distribution NetworkPMU data integrationPMU and conventional measurements integrated into a unified measurement setEXECUTEDSOTPDSOTPI-01
7Measurements from the Distribution NetworkObservability assessmentA numerical observability method is used in order to determine observability statusEXECUTEDSOTPDSOTPI-03
8Measurements from the Distribution NetworkCalculation of the state vectorState estimation algorithm is carried outEXECUTEDSOTPDSOTPI-02
9Measurements from the Distribution NetworkOutput of State Estimation toolEstimated state vector is communicatedREPORTDSOTPDSOI-02

Notes This part describes the possible scenarios of the use case. The scenarios should comply with the sequence diagrams in Sect. 2 of the template, so that every step describes one part of a communication or action. Apart from a normal success scenario, different failure scenarios or alternatives can be included to describe situations where preconditions are not satisfied or unwanted states are attained.

  • Event - Event triggering a step, specific for that use case.
  • Name of Process/ Activity - general classification of process/activity (e.g. data aquisition).
  • Description of Process/ Activity - more detailed description of the step.
  • Service - addresses the nature of the information flow. Possible: GET (The information receiver obtains information from the information producer after an implicit request.), CREATE (The information producer creates an information object.), CHANGE (The information producer performs an update of the information at the information receiver’s.), DELETE (The information producer deletes information of the receiver.), CANCEL/CLOSE (A process is terminated.), EXECUTE (An action or service is performed.), REPORT (The information producer supplies information of its own account.), TIMER (The actor which represents both information producer and receiver has to enforce a waiting period.), REPEAT (A number of steps has to be repeated until a break condition (stated in the field Event) is satisfied. The contemplated steps have to be added in parentheses.).
  • Information Producer and Receiver (Actor) - actors from actor list in section 3.1
  • Information exchanged (IDs) - ID of the information defined further in section 5

5. Information Exchanged

Information exchanged IDName of InformationDescription of Information ExchangedProtocol
I-01MeasurementsMeasurements from the Distribution Network (voltage magnitudes, active and reactive power injections/flows)ethernet TCP/IP, IP over GPRS
I-02State VectorVoltage magnitudes and angles of all network buses
I-03Observability statusThe result of the observability assessment of the Distribution Network, i.e.whether the state estimation problem can be resolved or not
I-04PMU MeasurementsMeasurements from PMUs (voltage phasors(angle and magnitude), current phasors(angle and magnitude))MQTT

Notes

  • Information exchanged ID - unique number (I-01,I-02…) for identification
  • Requirements to information data - optional, defined in section 6

6. Requirements (optional)

PMU field installation

7. Common Terms and Definitions

TermDefinition
Phasor measurementsMeasurements of magnitude and phase angle of voltage or current signals, which are synchronised via the global positioning satellite (GPS) system.
Pseudo-measurementAn injection whose value is obtained either from bus load forecasts or generation schedules. It is used as a substitute for a missing measurement in order to restore observability.
State vectorVoltage magnitudes and angles of all network buses

8. Custom Information (optional)

KeyValueRefers to Section