A Family of CIM EMS Exchange Standards based on CIM/XML (71970-552) - Static Network Model Exchange...

A Family of CIM EMS Exchange Standards based on CIM/XML (71970-552)

- Static Network Model Exchange (61970-452)- Schematic Layout Exchange (61970-453)

- Solved State Exchange (61970-456)- EMS Static Model Update (proposed)

- Analog Measurement Set?- Status Measurement Set?

- Contingency Definition Update?- …

Jay Britton

[email protected]

3 3

The Basic Model Exchange Business Problem

The members of an interconnection share a mutual necessity to achieve: Accurate assessment of grid reliability.

Appropriate, timely response to insecure conditions.

A pre-requisite to the above are: Accurate, up-to-date network models.

Consistent network models (at each responsible site).

In an interconnection, this requires: Exchange of models.

Exchange of solved analytical results.

2008 NERC Real-Time Best Practices Report: “Although defining the elements represented in internal network models is relatively

straightforward, the task force finds that defining the elements to be represented in external models is much more complex.”

“Issue #5: External Modeling and Data Exchange Practices Should be Improved by Explicit Reference to the Definition of the Wide-Area-View Boundary. A consistent, uniform set of modeling and data exchange practices, procedures, and standards are needed to support creation and maintenance of accurate external models…”

These requirements apply in real-time, near-future and long-term time frames.

4 4

There is high-level consensus about the right approach.

Basic Modeling: Each TSO is the authority for its own territory.

Each TSO exports its internal model to its neighbors and/or regional authority, and keeps it up to date.

Regional authorities assemble internal regional models from member TSO internal models.

(Sometimes reducing unnecessary parts.)

All parties assemble external models from the internal models of other sites.

Analysis: Responsibility may be distributed among cooperating sites.

Solution exchange is required, depending on the problem. Exchanged solutions should be based on consistent underlying

models.

These goals apply to both operations and planning. Operations focus is on as-built and near future changes.

If operations and planning share the same as-built base model, then the planning focus is on exchange of plans.

5 5

Expanding the Use Cases

Exchange of network models. EMS A and B are neighbors in an interconnection and therefore

each needs to represent the other as part of its external model.

Requires exchange of internal models.

Scope is limited to network data and measurement placements.

Common Modeling Source between planning and operations. One modeling application for the enterprise.

An EMS requires a model that covers any point in time.

Other targets require data for a specific “case”.

Exchange of solved cases. Several variations… Real-time exchange among different applications.

Real-time cases to study or planning.

Exchange of study or planning cases between different tools.

Import of study cases to EMS.

UCTE Day-Ahead. Study cases are generated for the next day by each TSO

representing the expected state of their internal network.

6 6

A Generic Model Exchange Business Process(ERCOT, WECC, …)

PRIMARY Interconnection

Model

Derived Model

TSO 1 External Model

Assembly of full primary model

Creation of derived target models

TSO 1 EMS

TSO 2 EMS

TSO n EMS

Interconnection EMS

TSO 1 Internal Model

TSO 2External Model


TSO n External Model

TSO n Internal Model

Interconnection Planning

Derived Model

TSO 1 Plans

TSO 2 Plans

TSO n Plans

7 7

Preview – We are working toward defining model partitioning into non-overlapping XML submodels that satisfy all of the use

cases.

Global Model Objects

Regional EMS Static Model

Bndry



Bndry

Partition by Object Instance using Model Authority Sets

Par

titio

n by

CIM

Sch

ema

Ele

men

ts

Sked

Conn

Common Objects

Display Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

Solution

Measurements

Meas

State Variables

Topology

Measurements

Meas

Measurements

Meas

8 8

CIM Exchange(full, partial, incremental update)

The initial CIM model exchange (61970-452) standard focused only on transfer of complete models:

A Internal Model

A’s model of B

baProprietary / Home grown

Extract / Merge Tools

Proprietary / Home grown

Extract / Merge Tools

CIM import / export

System A Local Vendor

Model

System A Import Model

B’s Model of A

B Internal Model

System B Local Vendor

Model

System B Import Model

CIM import / export

System A EMS System B EMS

9 9

A More Desirable Process

CIM ModelerFullInterconnectionModel


EMS at Site BEMS at Site A

System A Source

System B Import

boundary

System B Source

System A Import

boundary

My A Region(reduced & renamed)

My B Region(reduced & renamed)

CIM Translator A

EMS AProprietary Model Format

CIM Translator B

EMS BProprietary Model Format

CIM/XMLModel Exchange

Interface

a b

Site A makes a change:

1. A changes its ModelAuthoritySet using its CIM modeller.

2. A imports the change into its EMS.

3. A exports the change to B.

4. B receives the change (full or incremental), updating A’s ModelAuthoritySet within its CIM modeller.

5. B renames any new elements and repeats any reduction of A’s ModelAuthoritySet.

6. B imports the new model into its EMS.

10 10

Merge/Extract with Model Authority Sets

Each object is in one and only one set.

Simple labeling technique for assigning responsibility.

Associations connect some objects that are in different sets.

Currently directional from n to 1 (“foreign key” convention) – under discussion.

Regional Sets: No associations with other

regional sets.

External associations to boundary sets only.

Boundary Sets: External associations from

regional sets.

External associations with other boundary sets.

A regional set may be referentially validated independent of other regional sets.

Modeling processes can proceed independently in each region.

Goal: Maximize independence.

Design boundary sets to achieve:

Minimum data Infrequent change

Model Authority SetB

Model Authority SetA

Model Authority SetC

A-B boundaryMAS

B-C

bou

ndar

yM

AS

A-C

bou

ndar

yM

AS

11 11

Typical North American Boundary

Model Authority Set C

A-C Boundary

Set

CN


TT LS

A Region Transmission Line

C Region Substation

m

Tie Line Metering Point

T

T

CB

CN

T

T

CB

T

T

CB

T

BB

ST

GEO=’C’

LN

GEO=’A’

12 12

Typical UCTE Boundary

Model Authority Set CA-C Boundary

Set

CN


T

T

CB

CN

Tie Line

C Region Substation

m

T

T

CB

T

T

CB

Tie Line Mid-point

A Region Substation

CN

T

BB

TLST

T

T

CB

CN

T

T

CB

T

T

CB

T

BB

TLSTCN

STST

GEO=’C’GEO=’A’

LN=’X-Y’

ST=’X’ ST=’Y’

13 13

Hierarchical Process Definition for an Interconnection

Bottom level.

No significant differences.

Export changes as the model authority.

Import externals from the full interconnection model.

Upper level:

Manages boundary sets.

Creates the full interconnection model.

Model quality evaluation.

Study state estimation.

Derives operational model in the same manner as lower levels.

Different reduction criteria.

Design extends to any number of hierarchical levels.

CIM Modeler




System A Source

System B Import

boundary

System B Source

System A Import

boundary



CIM Translator A


CIM Translator B


a b

FullInterconnectionModel

System A Import

System B Import

boundary x

Upper Level Reliability Model

EMS at Upper Level Authority

CIM Translator

EMS Upper LevelProprietary Model Format

14 14

Consolidating Planning with Operations

CIM Modeler




System A Source

System B Import

boundary

System B Source

System A Import

boundary



CIM Translator A


CIM Translator B


a b

FullInterconnectionModel

System A Import

System B Import

boundary x

Upper Level Reliability Model

EMS at Upper Level Authority

CIM Translator

EMS Upper LevelProprietary Model Format

Interconnection Planning Model

Planning System

CIM Translator

Planning SystemProprietary Model Format

Full interconnection model is the common source for all models.

Interconnection planning shown on diagram.

No procedural difference required to support analytical functions running at any level for any purpose.

Planning adds other requirements.

New information modeling in CIM.

Accommodate bus-oriented apps.

Add short circuit, dynamics, etc.

Incremental model standard expands to model plans.

CIM modeling applications need to have a temporal axis.

2007 EPRI “CIM for Planning” project.

Goal is eliminate duplication of modeling.

15 15

The Naming Problem

PRIMARY Interconnection

Model

Regional External Model

TSO 1 External Model

Assembly of full primary model

Creation of derived target models

Model Authority 1 EMS

Model Authority 2 EMS

Model Authority n EMS

Regional EMS


TSO 2External Model


TSO n External Model

TSO n Internal Model

Name Registry

Name translation point

16 16

Roles in Model Exchange

Key modeling roles in an interconnection:

Model Authority The official source of data for a particular part of the network.

Usually the TSO (Transmission System Owner/Operator)

Model Quality Broker (optional) Arbitrates boundary definitions.

Receive model authority data.

Assemble a complete interconnection model.

Validate interconnection model.

Distribute updates to model.

End User Uses the models for some operational or planning purpose.

Creates analytical cases.

17 17

Adding Support for Analytical Processes

The 61970-452 standard exchanged EMS models.

Did not deal with planning (‘bus-branch’ models).

Did not support power flow solution exchange (or any other type of analytical result).

Several recent efforts defined other needed support.

2007 EPRI ‘CIM for Planning’

2008 UCTE Day Ahead Congestion Analysis

2008-2009 EPRI ‘CIM for Dynamics’

2009 IEC WG13 Goals

Unify and formalize UCTE and CIM for Planning results:

Capture CIM changes in CIM14.

Complete 61970-456 specification for Solved Power System State Exchange.

Solidify building block concept for a family of standards.

CIM modularized by ‘profile data groups’.

18 18

Existing UCTE Process for Day-Ahead Congestion Analysis

Daily Process:

1. Each TSO constructs power flow cases representing the planned operation for each hour of the following day.

2. Each TSO gets its neighbors cases and conducts congestion analysis studies focused on its own territory.

Cases typically generated and analyzed with planning tools.

Case Format:

Power flow format unique to UCTE.

Bus-branch network topology.

Each case is a single point in time. Load and generation values at each bus.

Specific targets for controls (regulated voltages, regulated flows).

Status of branches (in or out of service).

19 19

Current UCTE Day-Ahead Process

text

text

text

TSO

X-NodeList

TSO

TSO TSO TSO

TSO My TSO

My TSO

Export my TSO Model to UCTE Server

Import neighbor TSOs from UCTE Server

Merge

Impo

rt a

ll T

SO

mod

els

to

UC

TE

Ser

ver

TSO

TSO

TSO

UCTE Model Server

My TSO’s Cases for Export

My TSO

Model Maintenance

text

TSO

TSO TSO TSO

TSO My TSO

My TSO’s Congestion Analysis Model

text

TSO

TSO TSO TSO

TSO My TSO

Market

Outcomes

Next Day’s Case Development

20 20

Requirements AnalysisData Modularity

Equipment. Identifies equipment and

describes basic characteristics.

Connectivity. Describes electrical

connectivity that would be input to topology processing.

Schedules. Describes input to functions

that derive parameters for a specific point in time.

Analogs. The set of SCADA values for

analog measurements for a particular point in time.

Status. The state of switches – input to

topology processing.

Topology. The result of topology

processing. i.e. Description of how equipment connects into buses and how buses makeup connected systems.

Scheduled. This is the result of time

scheduling to develop input for a case.

State. This is the set of state variables

used in the mathematical formulation that the algorithms work with.

21 21

Requirements Analysis

In an EMS environment:

1. A modeler supplies Equipment + Connectivity + Schedules to the EMS.

2. Switch states and other parameters may be changed by telemetry or manual entry.

3. The EMS code develops Topology + Scheduled data for the desired case.

4. Manual override of the case input is allowed.

5. Algorithm develops solved State.

In a planning environment:

1. A ‘base’ version of case input is selected.

2. Manual override of the case input is allowed.

3. Algorithm develops solved State.

Both environments feed the same case data (Equipment + Topology + Scheduled) into the solution applications.

Main question is how to address the different starting points.

22 22

Requirements Analysis

Receivers of solved cases often need to recreate the case input.

Since there is normally the possibility of manual override of data, cases cannot simply be recreated from 452 static model data.

This means we need to define exchange of Topology + Scheduled data as well as State.

If we need to exchange Topology + Scheduled anyway,

A family of profiles are desired such that use cases may bypass Connectivity and Schedules where that makes sense.

Propose two standards:

Static Model Exchange

Solved Power System State Exchange

We should be able to construct profiles for all use cases from these.

EMS and planning.

Real-time and future.

Bus versus breaker detail.

State estimator and power flow.

23 23

CIM Design

Topology

TopologicalNodes (i.e. buses) in EMS represent the collection of ConnectivityNodes that are connected by closed Switches -- the result of topology processing.

Objective: don’t force Connectivity modeling if the usage only demands Topology.

Solution: establish direct relationships from Terminals to each. Terminal ConnectivityNode

Terminal TopologicalNode

Scheduled

Scheduled data is essentially starting conditions for state variables -- additional modeling is not required.

State is modeled in a new collection of SV (state variable) classes.

State Variables profile data group may be used to present starting conditions, solved state or indeed, any set of values for state variables, depending on the business usage.

24 24

IEC Static Model Exchange Profile (61970-452)

Equipment

+ [Connectivity]

+ [Schedule]

Ref (static model)

+ Topology

+ State Variables

IEC Solved State Exchange Profile (61970-456)

25 25

Solved State

Metadataby

File Type

State Variables

TSO Topology

TSO Equipment Model

ACLineSegment

ControlArea

CurrentLimit

CurveData

EnergyConsumer

FossilFuel

GeneratingUnit

GeographicalRegion

HydroGeneratingUnit

HydroPump

MutualCoupling

NuclearGeneratingUnit

OperationalLimitSet

PhaseTapChanger

PowerTransformer

RatioTapChanger

ReactiveCapabilityCurve

RegulatingControl

SeriesCompensator

ShuntCompensator

SubGeographicalRegion

Substation

SvPowerFlow SvShuntCompensatorSections SvTapStepSvVoltage

Switch

SynchronousMachine

Terminal

Terminal (about)

ThermalGeneratingUnit

TieFlow

TopologicalIsland

TopologicalNode

TransformerWinding

VoltageLevel

VoltageLimit

WindGeneratingUnit

UCTE Common Objects BaseVoltage OperationalLimitType

ControlAreaGeneratingUnit

LoadResponseCharacteristic

26 26

Profile Specification – File Types TSO Equipment Model Files

Equipment All equipment modeled by a given TSO.

- Includes Terminal objects.

Switches only if they are to be retained in studies. Equivalent generator at X-nodes.

Regulating Control: RegulatingControl targetRange for each voltage and flow control.

Topology Files X-node Boundary File

TopologicalNodes at tie midpoints.

TSO Files TSO TopologicalNode objects Terminal ‘about’ objects

- TopologicalNode association

- Connected attribute indicates open/close end

State Variable Files SvVoltage at TopologicalNodes

SvPowerFlow at GeneratingUnits, EnergyConsumer

SvShuntCompensatorSections and SvTapStep

27 27

Partitioning into Files by TSO

TSO Equipment Model

TSO Topology

TSO Equipment Model

State Variables

X-nodes

TN

TSO Topology

TN

Tie Line

B Region Substation

m

T TLS

T TLS

Tie Line Mid-point

A Region Substation

TLST

TN

TLST

T TLS

T TLS

State Variables FL

FLFL FLV VFL

FL

FL FL FL

FL

FL

TaTa

EG T

Ta

Ta

Ta

EGT

Ta

Ta

FL

FL

FL

Ta

Ta

Ta Ta

Ta

Ta

Ta

UCTE Common Objects BV

28 28

Complete View of Partitioning Into Files

GlobalMA

Regional Solved Case

Equipment Model

Topology

State Variables

Xnode

RegionalSolved Case

Equipment Model

Topology

State Variables

RegionalSolved Case

Equipment Model

Topology

State Variables

Xnode

Partition by Object Instance using Model Authority SetsP

artit

ion

by

CIM

Sch

em

a E

lem

en

ts

Common Objects

29 29

UCTE Interconnection Solution

GlobalMA

Regional Model

Equipment Model

Topology

Xnode

Regional Model

Equipment Model

Topology

Regional Model

Equipment Model

Topology

Xnode

Partition by Object Instance using Model Authority SetsP

artit

ion

by C

IM S

chem

a E

lem

ents

Common Objects

Global SolutionState

Variables

30 30

Dependency Relationships to be

Expressed in Headers

Equipment Model

TopologyState

VariablesCommon Objects

C1 S1T1E1

E1.1

T1.1

T1.2

T1.3

S10

S9

S8

S7

S6

S5

S4

S3

S2

S12

S11

31 31

61970 Profile Data Groups

61970-xxx Profile

61970-452Profile

Equipment Model

61970-456 Profile

Topology

State Variables

61970-453 Profile

Schedules

Connectivity

Schematic Layouts

Measurement Set

Measurement Specifications

32 32

Partitioning of EMS Static Model



Bndry



Bndry


Par

titio

n by

CIM

Sch

ema

Ele

men

ts

Sked

Conn

Common Objects

Display Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

33 33

Partitioning of EMS Solved Cases



Bndry



Bndry


Par

titio

n by

CIM

Sch

ema

Ele

men

ts

Sked

Conn

Common Objects

Display Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

Sked

ConnDisplay Layout

Equip Model

Solution

Measurements

Meas

State Variables

Topology

Measurements

Meas

Measurements

Meas

34 34

61970-553 Display Layout Exchange

Purpose: To exchange schematic display layouts accompanying model or solution

exchanges.

Corresponds to the part of display maintenance work that normally goes with model maintenance.

Defines graphic objects used in the sender’s displays: Usually linked to a model object, but can also be background.

One or more location coordinates. (Optional glue points.)

Graphic style reference.

Does not define: Interpretation of graphic style references.

Diagram exchanges must first agree on a set of style references. Receiver provides the graphic style interpretation models for their display

management software.

Result: Layouts and names of things should be familiar.

Exact replication graphically is likely only when sender and receiver applications are the same.

Exact replication functionally is likely only when sender and receiver applications are the same.

35 35

Display Layout UML Proposal

class Domain Objects

DiagramObject

+ offset: int+ offsetDirection: int+ rotation: int

DiagramObjectPoint

+ sequence: int+ xPosition: float+ yPosition: float+ zPosition: float [0..1]

DiagramObjectGluePoint

IdentifiedDiagramObject

DiagramObjectStyle

+ drawingOrder: int+ name: char


VisibilityLayer

IdentifiedObject

A DiagramObjectStyle is optional. If so the receiver is supposed to find a graphical shape that is relevant to the actual subtype of the IdentifiedObject associated with.

If the glue points connects points at different cooridantes the symbolsize matters.

«enumeratio...CoordinateSystem

gps rk90

DiagramObjectSet


Diagram

+ coordinateSystem: CoordinateSystem+ x1InitialView: float+ x2InitialView: float+ y1InitialView: float+ y2InitialView: float

How do we represent hierarchies of DiagramObjects containing each other and manage the references from them to the CIM equipment model?

1..*

1

0..1

+Point

2..*

1..*

+DiagramObjectSet

0..1

1..*

0..*

+IdentifiedObject

0..1 0..* 0..*

+Style

0..1

1..*

+DiagramObject

1

36 36

UCTE Case – Display Layout Exchange

Display Bndry

TSO Equipment Model

TSO Topology

TSO Equipment Model

Display Layout

X-nodes

TN

TSO Topology

TN

Tie Line

B Region Substation

m

T TLS

T TLS

Tie Line Mid-point

A Region Substation

TLST

TN

TLST

T TLS

T TLS

Display Layout GO

GOGO GOGO GO GO

TaTa

EC T

Ta

Ta

Ta

ECT

Ta

Ta

GO

GO

Ta

Ta

Ta Ta

Ta

Ta

Ta

UCTE Common Objects BV

37 37

Profile Specifications -- Packaging

Files

A business exchange contains 1-n files.

File bodies follow 61970-552 except that some have “dangling associations”.

MRIDs are used as RDFIDs.

File naming convention TBD

Header references dependent files.

When multiple files are used to transmit a complete model – as defined by some CIM profile…

Files are zipped together.

Each XML expression of an object, association or attribute appears in one and only one file.

Associations are defined from the “many” end as with the existing 452 exchanges that have been interop tested.

Total profile transmission is the union of the file body contents.

A complete valid XML expression can be obtained simply by concatenating the RDF/XML in the file bodies.

38 38

Business Usage Profiles for 61970-45x

Typically, will need to add specific usage decisions for their exchange agreements.

Boundary conventions

Is there a model broker?

Naming

Slack variable treatment

EMS or planning or both?

File packaging.

39 39

Conclusions

A great deal of progress has been made.

Tools exist.

Adoption is lagging – especially in North America.

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A Family of CIM EMS Exchange Standards based on CIM/XML (71970-552) - Static Network Model Exchange...

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