1. CTS – CIM Topology Store
Implementation of an RDF-based versioning system for the CIM using the topology difference model
Mathias Uslar
Arnhem, Netherlands xx

2. Agenda Adressed problem Use Cases Used technologies
Solving the problem
Implementation
Results
Further work

3. Adressed problem Data must be exchanged between grid providers
Narrowly meshed grids
New challenges for utilities
Power grids are constantly evolving
Changes have to be tracked and made persistent
Serializing the grid using XMl leads to bloat
High amounts of data
Difficult to be validated

4. Use Cases We have identified four main use cases for our system
Regular exchange of full topology models
Exchange of partial topology models
Recombining partial topologies to create a full one
Tracking and versioning topology histories

5. Used technologies – Semantic Web
XML
eXtensible Markup Language
RDF
Resource Description Framework
OWL
Web Ontology Language
SPARQL
SPARQL Protocol And RDF Query Language
Query language for RDF
Semantic Web Stack (Quelle: W3C)

6. Technologies – Common Information Model
Focus: Representing topology data
CIM is serialized in RDF
Markup of the PsyCor-SmallModel (Source: CIMPhony by Dr. Alan McMorran, University of Strathclyde)
<?xml version="1.0" encoding="UTF8"?>
<rdf:RDF xmlns:rdf="
xmlns:cim="
<cim:SubControlArea rdf:ID="_1">
<cim:Naming.name>HANGER18</cim:Naming.name>
<cim:SubControlArea.HostControlArea rdf:resource="#_14"/>
</cim:SubControlArea>
<cim:Substation rdf:ID="_2">
<cim:Naming.name>AIRPORT</cim:Naming.name>
<cim:Substation.MemberOf_SubControlArea rdf:resource="#_1"/>
<cim:Substation.LoadArea rdf:resource="#_15"/>
</cim:Substation>
<cim:VoltageLevel rdf:ID="_3">
<cim:VoltageLevel.highVoltageLimit>350</cim:VoltageLevel.highVoltageLimit>
<cim:VoltageLevel.lowVoltageLimit>340</cim:VoltageLevel.lowVoltageLimit>
<cim:Naming.name>VL_AIRP_345</cim:Naming.name>
<cim:VoltageLevel.MemberOf_Substation rdf:resource="#_2"/>

7. Solving the problem – the difference model
Evaluating the existing format according to deVos
Non-conform to the RDF-standard
Uses syntax with insertion and deletion operations
Developed and evaluated two new formats
Conforming the RDF-standard
Evaluating replacement and insertion and deletion approaches
Improved parsing for machines
More robust due to pre- and postconditions

8. Solving the problem – Difference model
Example: changing a load
<cim:EnergyConsumer rdf:ID="_242C8FDFE7334E9BA603449C87D89903">
<cim:Naming.name>BRADFD</cim:Naming.name>
<cim:EnergyConsumer.qfixed>0</cim:EnergyConsumer.qfixed>
<cim:EnergyConsumer.conformingLoadFlag>true</cim:EnergyConsumer.conformingLoadFlag>
<cim:EnergyConsumer.pfixed>0.2</cim:EnergyConsumer.pfixed>
<cim:Equipment.MemberOf_EquipmentContainer rdf:resource="#_95D88A1500A4E7EB95B01E23C2FEF7D"/>
<cim:EnergyConsumer.LoadArea rdf:resource="#_BA B0645A7AC8EA57B6249D537"/>
</cim:EnergyConsumer>
<cim:EnergyConsumer rdf:ID="_242C8FDFE7334E9BA603449C87D89903">
<cim:Naming.name>BRADFD</cim:Naming.name>
<cim:EnergyConsumer.qfixed>0</cim:EnergyConsumer.qfixed>
<cim:EnergyConsumer.conformingLoadFlag>true</cim:EnergyConsumer.conformingLoadFlag>
<cim:EnergyConsumer.pfixed>0.2</cim:EnergyConsumer.pfixed>
<cim:Equipment.MemberOf_EquipmentContainer rdf:resource="#_95D88A1500A4E7EB95B01E23C2FEF7D"/>
<cim:EnergyConsumer.LoadArea rdf:resource="#_BA B0645A7AC8EA57B6249D537"/>
</cim:EnergyConsumer>
Differenzformat dahlem
<dm:DifferenceModel rdf:about="
<dm:reverseDifferences>
<rdf:Statement>
<rdf:subject rdf:resource="
<rdf:predicate rdf:resource="
<rdf:object>0.2</rdf:object>
</rdf:Statement>
</dm:reverseDifferences>
<dm:forwardDifferences>
<rdf:object>30</rdf:object>
</dm:forwardDifferences>
</dm:DifferenceModel>
Differenzformat nach deVos
<dm:DifferenceModel rdf:about="
<dm:forwardDifferences rdf:parseType="Statements">
<rdf:Description rdf:about="#_242C8FDFE7334E9BA603449C87D89903">
<cim:EnergyConsumer.pfixed>30</cim:EnergyConsumer.pfixed>
</rdf:Description>
</dm:forwardDifferences>
<dm:reverseDifferences rdf:parseType="Statements">
<cim:EnergyConsumer.pfixed>0.2</cim:EnergyConsumer.pfixed>
</dm:reverseDifferences>
</dm:DifferenceModel>
Difference format dahlem2
<rdf:Statement>
<rdf:subject rdf:resource="
<rdf:predicate rdf:resource="
<rdf:object>30</rdf:object>
<dm:replaces>
<rdf:object>0.2</rdf:object>
</rdf:Statement>
</dm:replaces>
<cim:EnergyConsumer rdf:ID="_242C8FDFE7334E9BA603449C87D89903">
<cim:Naming.name>BRADFD</cim:Naming.name>
<cim:EnergyConsumer.qfixed>0</cim:EnergyConsumer.qfixed>
<cim:EnergyConsumer.conformingLoadFlag>true</cim:EnergyConsumer.conformingLoadFlag>
<cim:EnergyConsumer.pfixed>30</cim:EnergyConsumer.pfixed>
<cim:Equipment.MemberOf_EquipmentContainer rdf:resource="#_95D88A1500A4E7EB95B01E23C2FEF7D"/>
<cim:EnergyConsumer.LoadArea rdf:resource="#_BA B0645A7AC8EA57B6249D537"/>
</cim:EnergyConsumer>

9. Solving the problem – regional model
According to Britton: Designing Model Exchange Processes with CIM and ’RMA Sets’
Three types of regions:
Base region
Border region
Aggregated region
Regional model (Source: Britton, Areva T&D

10. Solving the problem – Versioning and SPARQL
Versioning system
Absed on the difference format
Implements the regional model
SPARQL query system
Querying of versioned topologies
Supports aggregated regions

11. Our solution
The new formats are more standard-compliant (RDF), more robust than the existing one and incorporated more information
There was no known existing solutions for versioning topologies in CIM (end of 2006)
There was no known implementation of the regional model for CIM (end of 2006)

12. Implementation Backend system Web Services Database MySQL Jena
Apache Tomcat
Apache Axis
Database MySQL
Jena
RDF-Triple-Store for MySQL
Java API
SPARQL implementation
Command line client
VMWare for Windows/Linux
System overview (Source: Own graphic)

13. Results Compatibility to other CIM implementations
Interop #6 tests have been passed completetely
Improved difference formats:
More robust
RDF-compliant
More information
Implementation fo a versioning system and the regional model
More functionality:
Validating against CPSM (2.0, experimental 3.0)
Notification ( , Jabber)

14. Further work Improving the client Keeping data solely as RDF
GUI for endusers
Keeping data solely as RDF
Technology breach: versioning data is kept in a relational database
Benchmarks
RDF-Triple-Stores are too slow nowadays
SPARQL has a lot potential for improvements
„The next SQL“
Current research: DML & DDL, algebra

15. Thanks for listening
Time for questions